WirelessBR

WirelessBr é um site brasileiro, independente, sem vínculos com empresas ou organizações, sem finalidade  comercial,  feito por voluntários, para divulgação de tecnologia em telecomunicações 

Blog Comunitário
Diversos:
 Skype - VoWLAN ou VoWi-FI (Voice over Wi-Fi) - VoWLAN (Voice over WLAN)

[O site WirelessBR está descontinuado. Esta é uma página de arquivo]

O Site WirelessBR é parte integrante da ComUnidade WirelessBrasil
  Página mantida
por Helio Rosa   Atualizada em 10/06/06   Sobre "Direitos" ("Rights")

Skype - VoWLAN ou VoWi-FI (Voice over Wi-Fi) - VoWLAN (Voice over WLAN)
 

 
ComUnidade WirelessBrasil

Site WirelessBR

Complemente sua pesquisa: Google
(com opção de páginas em português)

 


SKYPE



Artigo
Transcrito do WebInsider   Visite!

Voip via aparelho é melhor do que por software       [10/01/2005 ]
 

Usar o Skype e falar de graça com quem está em outra máquina é bom. Mas o uso do aparelho voip é diferente e deve ser considerado pelas vantagens que apresenta. Entenda por quê.

Diego Moralles

Feliz Ano Novo para todos os leitores do Webinsider. Hoje vamos falar do uso do VoIP por software e por hardware.

Qual das duas formas de utilização é a melhor e mais viável para a sua residência ou sua empresa? Qual delas traria um retorno mais satisfatório para você?

As respostas para essas perguntas e algumas outras estão a seguir.

O VoIP por software funciona como no hardware. A qualidade é a mesma, os protocolos abordados são os mesmos (veja matéria ao lado). A diferença é que, ao instalar o programa voip em uma máquina, essa terá que atender requisitos mínimos: um kit multimídia (um microfone e um fone de ouvido ou caixas de som) para poder se comunicar quando efetuar uma ligação. Você só poderá ligar para uma outra pessoa também tenha o programa no computador e atenda os mesmo requisitos do software.

Um software muito conhecido é o Skype. Funciona muito bem em casa, mas por uma série de motivos não é a melhor opção em empresas.

Usando o computador. Se uma empresa deseja 20 linhas voip e decide utilizar o Skype ou outro software qualquer, precisará de 20 computadores com 20 kits multimídia.

Se um dia houver um corte de energia, o que aconteceu com as linhas voip? A telefonia comum tem sua própria fonte de energia. Em caso de blecaute, você ainda pode falar normalmente ao telefone. O VoIP não tem essa fonte de energia. Neste caso a empresa teria que instalar 20 no-breaks para não perder a comunicação com seus clientes e associados na falta de energia elétrica.

O custo deste investimento adicional pode impactar. Algumas pessoas sugerem, para o caso de falta de energia, manter apenas cinco ou seis linhas voip, de forma a usar apenas cinco ou seis no-breaks. Mas seria uma boa solução? Se a empresa adquiriu um produto que dá 20 linhas, por que usar apenas cinco ou seis?

Com o aparelho voip. Se esta empresa optar pelo hardware ao invés do software, isso não seria problema. Todo e qualquer CPD que possui um servidor web, conta obrigatoriamente com um no-break. Possivelmente tem também o PABX ligado em outro no-break ou no mesmo. Se a empresa comprasse um aparelho de 8, 16 ou 32 linhas voip existente no mercado, só teria o trabalho de ligar esse aparelho no no-break que já existe na empresa. Em caso de queda de energia, ela iria continuar garantindo as 20 linhas que comprou. Vocês entenderam essa vantagem do aparelho?

Com o aparelho VoIP, você poderá ligar para qualquer pessoa que tenha um telefone comum, um celular, um pager, um fax, um PABX ou mesmo um aparelho voip, sem se preocupar com mais nada.

Na residência ou escritórios muito pequenos, por questões de custo, seria melhor utilizar o programa VoIP. Mas só por questões de custo. Do contrário, em termos de conforto e praticidade, o aparelho VoIP traz mais vantagens do que o software no computador, mesmo nas residências. Por exemplo:

Comprando e instalando um aparelho VoIP em sua casa, você não precisaria necessariamente ter um computador. Ou seja, quem não tem computador ainda assim pode fazer ligações voip. Os aparelhos se adaptam facilmente a qualquer tipo de acesso à internet, até mesmo o acesso discado.

Também não seria preciso pagar um provedor para acessar à internet quem quiser utilizar um provedor gratuito. Você apenas conecta o aparelho em sua linha telefônica comum, coloca o aparelho de telefone no aparelho voip e pronto. Ao fazer ligações locais você utilizaria sua linha comum; já as ligações interurbanas ou internacionais seriam pelo VoIP, para você pagar como uma ligação local.

Algumas pessoas perguntam: "Qual a vantagem de eu colocar um VoIP em minha casa usando linha discada se vou ter que pagar pela ligação?". Sim, é verdade, você pagará pela ligação, mas seria uma ligação local. Ou seja, você pagaria somente os pulsos utilizados pela tarifa local.

Ao fazer uma ligação DDD ou DDI, você paga as taxas do DDD ou DDI, os minutos de conversação e os pulsos. Com o aparelho VoIP em uma linha discada, você pagaria somente os pulsos. Bem mais em conta.

Aparelho pode ser usado em outros lugares. Outra vantagem interessante é que os aparelhos VoIP recebem um número fixo. Hoje com o telefone comum, o seu número de telefone fica preso à sua residência. Se você pegar seu aparelho comum e ligá-lo na casa de algum vizinho, o número daquele telefone será o do seu vizinho.

Com o VoIP isso não acontece. Se você pegar o seu aparelho VoIP e ligá-lo na casa de seu vizinho, ele mantém o mesmo número de telefone. Os aparelhos podem acessar a internet por qualquer meio. Ou seja, você pode levá-lo na viagem de família, para a chácara do tio, ou para seu apartamento ou uma casa alugada na praia. Basta instalar para falar voip e receber suas ligações sem que as pessoas percebam que você está em outro lugar, mais ou menos como funciona com o celular.

Um argumento de quem prefere o uso do software ao aparelho voip é dizer que se o aparelho quebrar ou der algum problema, não poderá fazer e receber ligações. É verdade, assim como o computador também pode dar problemas. É mais barato e rápido trocar o aparelho VoIP do que mandar o computador para a assistência técnica.

Há vantagens são fortes e vale a pena avaliar a compra de um aparelho.

Desconfie de preços muito baixos. Outra dica importante: existem muitas empresas que vendem aparelhos voip a um custo muito baixo em relação à concorrência, pois não pagam taxas e impostos pelos produtos vendidos.

Um grande número desses aparelhos é importado ilegalmente. Como o fornecedor está fora do Brasil, pode haver dificuldades na devolução do aparelho por insatisfação quanto ao serviço. Por isso, antes de comprar o aparelho, verifique com o vendedor se há garantia, qual é a empresa que vende os aparelhos para eles, onde ela fica a empresa caso você queira visitar e EXIJA a nota fiscal do aparelho. São dicas importantes para que você possa utilizar o voip sem dores de cabeça e sem incentivar a concorrência desleal que infelizmente existe. [Webinsider]
 


NOTÍCIA
Empresa brasileira lança Skype no telefone fixo

Quarta-feira, 2 março de 2005 - 14:45
Daniela Braun - IDG Now!

A brasileira Leucotron lança, nesta quarta-feira (02/03), o Skyvoice, um sistema que permite o uso do telefone fixo, residencial ou PABX, nas chamadas sobre IP (Internet Protocol) pelo software Skype, da norte-americana Skype Technologies S.A..
 
A solução residencial para usuários de banda larga, que custa 372 reais, engloba um hardware - do tamanho de um modem ADSL - conectado ao micro e ao aparelho telefônico, que fica dedicado à chamada pelo Skype .
 
O sistema é acompanhado de um software, também usado na versão corporativa, que funiona como uma agenda para gerenciar os contatos telefônicos do Skype e agilizar as chamadas.
 
A vantagem, segundo o fornecedor, é a mobilidade, já que o equipamento substitui o microfone do micro, embora a máquina tenha de estar ligada e conectada para que o sistema funcione.
 
Para o mercado corporativo, a empresa lança o Skyvoice TR, que é embutido no PABX e será vendido a 171 reais por comunicação - o equivalente a um preço por linha. "Com isso, a empresa ganha mais uma opção de economia com chamadas telefônicas e garante todas as funcionalidades que o PABX oferece", explica Antônio Cláudio de Oliveira, diretor de marketing da Leucotron
 
Oliveira estima que, este ano, sejam comercializadas 20 mil unidades do Skyvoice, sendo 70% pra o mercado corporativo, que é a grande aposta da empresa para este lançamento.
 
O hardware  fabricado na planta da Leucotron em Santa Rita do Sapucaí (MG) também será exportado para países da América Latina. Em 2006, a previsão é vender mais do que o dobro de unidades em relação a este ano, informa Oliveira.
 
A novidade da Leucotron segue uma tendência de integração do Skype a outros serviços de comunicação, como o SMS (Short Message Services), cujos testes foram anunciados pela inglesa Connectotel na semana passada, e de uso do sistema de VoIP em celulares e dispositivos com acesso sem fio (Wi-Fi) lançado pela operadora européia Carrier Devices Ltd.. no início de fevereiro. 
 

Transcrito do site TelNext    Visite!     Fonte: Google

COMUNICAÇÃO SEM CUSTO ATRAVÉS DA INTERNET

Comunicação de voz através da Internet já é uma realidade . Utilizando o programa de comunicação Skype gratuitamente você pode conversar com qualquer pessoa que tenha instalado o Skype . Além de um micro com placa de som e acesso Internet você só precisa de um headset .

O melhor programa para conversas de voz da atualidade é o Skype. Com ele você realiza conversas de voz em tempo real com uma ou mais pessoas ao mesmo tempo. Além disso o Skype não é um programa complicado, dispensa configurações técnicas, funciona com qualquer tipo de acesso Internet, é em português e gratuito.

Com o Skype você pode se comunicar com outros Internautas em qualquer parte do Brasil e do mundo aproveitando seu acesso Internet e sem pagar nada mais por isso! Basta que você e a outra pessoa tenham o Skype instalado e funcionando.

Siga as orientações comece hoje mesmo a conversar com seus amigos através da Internet. Vamos lá?

Instalação do Skype

Faça o download do Skype no seguinte endereço:

http://www.skype.com/download.html

http://www.skype.com/skypeout/help.pricelist.html

Realizar um download nada mais é do que copiar um programa da Internet para o seu computador. Faça isso acessando o endereço acima, clicando no botão DOWNLOAD e salvando o programa SkypeSetup-Beta.exe em uma pasta de sua preferência.

Depois de concluir o download abra a pasta onde o programa SkypeSetup-Beta.exe foi salvo e rode-o (acione-o) clicando com o mouse 2 vezes sobre ele. Você verá a seguinte tela:

O Skype funciona em diversos idiomas, inclusive o Português. Selecione o idioma de sua preferência conforme mostra a figura abaixo e clique no botão OK para prosseguir a instalação.

O processo de instalação é relativamente simples. A única coisa que você precisa selecionar manualmente é a opção 'Eu aceito as condições de uso'. No restante é só clicar várias vezes no botão 'Avançar' até terminar a instalação. Veja:

Cadastramento inicial

Se essa é a primeira vez que você utiliza o Skype deve criar uma nova conta.
Clique na opção 'Eu gostaria de criar uma conta no Skype' e clique no botão 'Próximo'.

Em seguida preencha os dados do formulário. No campo 'Escolha um nome de usuário' digite seu apelido, e no campo 'Senha' digite uma senha para usar no Skype. A senha é você quem define. Repita a mesma senha no campo 'Repetir Senha'. Informe também seu email correto. Isso é importante para que você possa recuperar sua senha posteriormente, caso a esqueça.

Ative a opção 'Sim, eu li e aceito...'. A opção 'Store my password..' faz com que sua senha fique armazenada. Ative-a e você não precisará informar sua senha toda vez que ligar o Skype. Em seguida clique no botão 'Terminar'.

Se o apelido (nome de usuário) que você informar não for válido ou já estiver sendo utilizado por outra pessoa você receberá um aviso na parte superior da janela. Se isso acontecer simplesmente digite outro apelido. Evite utilizar caracteres especiais ou espaços no seu apelido. Prefira palavras simples com letras e números, como por exemplo: joao35, paula22, marcosrj, celsocarioca, etc.

Se o apelido for aceito uma nova janela abrirá com um formulário de dados pessoais. Preencha seus dados para que seus amigos possam localizá-lo com facilidade. Você não precisa preencher todos os campos mas recomendamos que você preencha ao menos o nome, sexo, idioma e país.

Veja o exemplo:

Ao terminar o preenchimento clique no botão 'Atualizar'.

Pronto! Agora você pode já pode utilizar seu Skype!

Localize seus amigos e inclua-os na sua lista do Skype

Na primeira vez que você usa o Skype sua lista de amigos está vazia como na imagem abaixo.

Para poder realizar ligações através do Skype você primeiro deve localizar a pessoa com a qual deseja conversar e adicioná-la na sua lista de amigos. Para isso clique na aba 'Iniciar' e em seguida clique na opção 'Encontrar um amigo'. Clicar diretamente na lupa no topo da janela do Skype tem o mesmo efeito. Ao fazer isso você verá uma janela onde deve digitar o nome da pessoa que deseja encontrar. Digite o nome e clique no botão 'Encontrar'

No exemplo acima procuramos por um amigo nosso digitando seu primeiro nome 'adnen' e clicando no botão 'Encontrar'. Digite o nome do seu amigo para localizá-lo. Apenas pessoas que possuem o Skype instalado e o utilizaram nos últimos 3 dias são encontradas.

Depois de localizar seu amigo (ou amiga) adicione-o ao seu Skype clicando com o botão direito do mouse no nome dele e selecionando a opção 'Adicionar para amigos'. Você verá uma janela com um espaço para digitar um texto. Digite alí um pedido de autorização e clique no botão 'Ok'. Seu amigo receberá o pedido e deverá autorizá-lo a adicionar seu nome na sua lista de amigos do Skype.

Como realizar e atender ligações

Depois de adicionar um amigo ao Skype clique na aba 'Amigos'. Clique 2 vezes com o mouse no nome do amigo com o qual deseja conversar. O Skype irá chamar seu amigo e assim que ele atender vocês poderão conversar em tempo real por voz. Para desligar clique no botão vermelho (fone no gancho).

Quando alguém liga para você uma campainha toca e a janela do Skype informa o nome da pessoa. Para atender a ligação é só clicar no botão verde (fone fora do gancho) e começar a falar. Para desligar clique no botão vermelho (fone no gancho). Estes 2 botões aparecem na parte de baixo da janela do Skype.

Falando com mais de uma pessoa ao mesmo tempo (Conferência)

No Skype existem 2 maneiras de falar com mais de uma pessoa ao mesmo tempo.

A primeira maneira é ligar para alguém e em seguida incluir uma ou mais pessoas na conversa. Para isso basta ligar para uma pessoa e durante a conversa clicar na aba 'Amigos', clicar uma vez no apelido da pessoa que deseja adicionar e clicar no botão de conferência. Você também pode incluí-la clicando com o botão direito do mouse sobre seu apelido e em seguida selecionando a opção 'Invite to Conference'.

A segunda forma de realizar conferências é selecionar todos os participantes antes da ligação. Para tanto clique na aba 'Amigos', mantenha a tecla CTRL (Control) pressionada e vá clicando nos apelidos das pessoas que deseja incluir na conferência. Depois solte a tecla CTRL e clique no botão de conferência. Todas as pessoas selecionadas entrarão na conversa ao mesmo tempo.

A versão 0.97 do Skype suporta até 5 usuários conversando ao mesmo tempo, contando com você.

O Skype possui muitos outros recursos que você irá descobrir à medida que for utilizando-o. Lembre-se que na página do TelNext onde o Skype está disponível para download existe um Fórum para que você possa trocar mensagens com outros usuários e sanar suas dúvidas. Faça uso. :-)


Coleção de Notícias - Fonte: Folha de S.Paulo  Busca Folha

1. Folha Online - Informática - Programa habilita micro a receber ligações de telefone convencional - 20/03/2005
... preço de uma ligação internacional. O lançamento da função SkypeIn, que é similar, foi prometida pelo Skype, concorrente do Teleo. O software também transfere para telefones fixos ou ... Using Teleo (discar com o Teleo). Ainda faltam ao Teleo alguns serviços oferecidos pelo concorrente. O Skype, além de ser gratuito, possibilita a troca de mensagens de texto e a ...
http://www1.folha.uol.com.br/folha/informatica/ult124u18187.shtml

2. Folha Online - Informática - Usuários de conexão sem fio poderão navegar com Skype - 03/03/2005
... 03/03/2005 12h05 Usuários de conexão sem fio poderão navegar com Skype da Folha Online Usuários britânicos de conexões sem fio poderão navegar e fazer ligações gratuitamente a partir de ... gratuitamente a partir de hoje. Isso porque a provedora de acesso Broadreach juntou-se à empresa responsável pelo Skype e, juntas, oferecerão o serviço em 350 hotspots. Para ...
http://www1.folha.uol.com.br/folha/informatica/ult124u18083.shtml 

3. Folha Online - Informática - 5,3 milhões de brasileiros têm banda larga em suas casas - 23/02/2005
... impacto sobre outras atividades, como a telefonia. No mês passado, mais de 400 mil brasileiros utilizaram o Skype, programa que permite a conexão telefônica via web, representando ... telefônica via web, representando um aumento de 65,8% no últimos 6 meses. O tempo médio de utilização do Skype, por usuário, foi de 23 minutos. Leia mais Banda larga responde por ...
http://www1.folha.uol.com.br/folha/informatica/ult124u18032.shtml 

4. Folha Online - Informática - Usuários poderão fazer ligações de VoIP em equipamentos móveis - 15/02/2005
... 02/2005 11h56 Usuários poderão fazer ligações de VoIP em equipamentos móveis da Folha Online Os usuários do Skype --software que permite fazer ligações telefônicas pelo computador- ... serviço em equipamentos móveis. Isso porque a fabricante de celulares Motorola fez uma parceria com o Skype, responsável pelo programa que já tem mais de 26 milhões de usuários em ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17978.shtml 

5. Folha Online - Informática - Tecnologia invade a aula e muda a maneira como alunos estudam - 09/02/2005
... do Fórum Social Mundial de Porto Alegre com boletins ao vivo, gravados com filmadoras digitais ou via Skype, programa de voz sobre IP. O conteúdo, disponível em cyber fam.pucrs.br ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17947.shtml 

6. Folha Online - Dinheiro - Acesso à internet muda hábitos de cidade de 7.500 habitantes no interior de SP - 06/02/2005
... com a tecnologia necessária. Atualmente, o departamento de compras da prefeitura já utiliza o software Skype -que permite fazer ligações telefônicas pelo computador- em suas compras, ...
http://www1.folha.uol.com.br/folha/dinheiro/ult91u93212.shtml 

7. Folha Online - Informática - Alternativas ao Skype vão além da conversa pela rede - 12/01/2005
... 12/01/2005 18h05 Alternativas ao Skype vão além da conversa pela rede da Folha de S.Paulo Na esteira do sucesso do Skype , que chegou a ter mais de 1 milhão de usuários conectados ... locais e internacionais sem custos para pessoas que também utilizam um netfone. Entre as alternativas ao Skype, destacam-se o Firefly 1.9 e o GloPhone 2.0 . Além da facilidade de ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17825.shtml 

8. Folha Online - Informática - Teste USP avalia IP Phone, que faz ligações usando o micro - 24/11/2004
... aparelhos, mas a qualidade deles é baixa e prejudica a clareza das conversas. Comparando o IP Phone com o Skype , popular programa de voz sobre IP, o primeiro não apresenta ... o primeiro não apresenta vantagens e perde em muitos pontos. Editoria de Arte/Folha Online Apesar de o Skype operar com protocolo proprietário, o seu uso é gratuito e não exige a ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17529.shtml 

9. Folha Online - Informática - Novo Kazaa tem recursos de telefonia via internet do Skype - 22/11/2004
... 22/11/2004 16h05 Novo Kazaa tem recursos de telefonia via internet do Skype da Folha Online A partir de agora, usuários do Kazaa poderão fazer ligações para qualquer lugar do mundo ... programa de troca de arquivos, oferece aos internautas o Kazaa v3.0 uma nova versão do programa integrada ao Skype --software de telefonia de voz sobre IP. "Esse tipo de serviço, ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17510.shtml 

10. Folha Online - Informática - Falha no Skype deixa PC vulnerável a ataques virtuais - 16/11/2004
... 16/11/2004 11h07 Falha no Skype deixa PC vulnerável a ataques virtuais da Folha Online Uma brecha de segurança no software Skype, um dos mais populares da telefonia via internet, permite ... execução de códigos perigosos ou à parada do sistema. A informação sobre a falha foi divulgada pela própria Skype. "Trabalhamos para consertar o problema e sugerimos que os ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17451.shtml 

11. Folha Online - Informática - EUA eliminam barreiras para telefonia de voz sobre IP - 10/11/2004
... cabo, telefonia e internet. Empurrão De olho nesse mercado, a Siemens criou um adaptador com o software Skype (voz sobre IP) com o qual o mesmo aparelho de telefone pode fazer ... De acordo com o site News.com o maior atrativo para o equipamento é a união entre os pedigrees Siemens e Skype. A primeira empresa está entre as maiores fabricantes de telefone do ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17400.shtml 

12. Folha Online - Informática - Mercado de voz sobre IP deve crescer 44,2% na AL em 2004 - 04/11/2004
... do Sul desencorajou investimentos pesados nos últimos anos. Leia mais Telefone comum poderá ligar para o Skype Especial Leia o que já foi publicado sobre telefonia via internet ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17352.shtml 

13. Folha Online - Informática - Brasil Telecom bloqueia soft de telefonia via web, dizem usuários - 03/11/2004
... operadora de telefonia Brasil Telecom estaria bloqueando o acesso de seus usuários de banda larga ao Skype, sistema gratuito de telefonia pela internet. A informação está em um ... página do programa da internet, em que usuários brasileiros discutem o problema com a equipe de suporte do Skype. No fórum , diversos usuários reclamam de não conseguir conectar- ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17342.shtml 

14. Folha Online - Informática - Empresa reduz tarifas do Skype no Brasil - 03/11/2004
... 03/11/2004 09h18 Empresa reduz tarifas do Skype no Brasil da Folha de S.Paulo O que era barato ficou uma pechincha. Desde quinta-feira, as tarifas de ligações para Brasil, França, ... Brasil, França, Turquia, Rússia e Japão via SkypeOut foram reduzidas em 63%. Isso quer dizer que um usuário do Skype em qualquer parte do mundo pode ligar, via micro, para um ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17324.shtml 

15. Folha Online - Informática - Telefone comum poderá ligar para Skype - 03/11/2004
... 03/11/2004 09h07 Telefone comum poderá ligar para Skype FERNANDO BADÔ da Folha de S.Paulo A parceira entre o sueco Niklas Zennström, 37, e o dinamarquês Janus Friis, 27, tem demostrado ... fato que não agradou às grandes gravadoras. Depois de vendê-lo para a Sharman Networks, eles criaram o Skype , que simplesmente elimina a necessidade de o usuário usar o telefone. ...
http://www1.folha.uol.com.br/folha/informatica/ult124u17323.shtml 

16. Folha Online - Informática - Veja como conversar via micro com conforto - 25/08/2004
... entre o TeraFone e um conjunto de caixas e microfone é que, quando o usuário recebe uma ligação (via Skype, por exemplo), ele toca como um telefone, o que significa que o ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16797.shtml 

17. Folha Online - Informática - Ligação internacional pela web custa R$ 0,07 por minuto - 25/08/2004
... de S.Paulo Muito parecido com um programa de mensagens instantâneas, como o ICQ ou o MSN Messenger, o Skype vem ganhando adeptos por facilitar a conversa de voz via internet. O ... adeptos por facilitar a conversa de voz via internet. O arquivo do programa é pequeno (3,1 Mbytes, em www.skype.com) e fácil de instalar. Feito isso, qualquer internauta pode ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16796.shtml 

18. Folha Online - Informática - Voz via internet reduz gasto com telefone - 25/08/2004
... Messenger-- possibilitam o bate-papo. Outro programa que viabiliza a conversa de voz por meio da rede é o Skype. O uso de VoIP também pode reduzir os gastos ao realizar, via micro, ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16795.shtml 

19. Folha Online - Informática - Skype agora faz ligações para telefone convencional - 04/08/2004
... 04/08/2004 10h04 Skype agora faz ligações para telefone convencional da Folha de S.Paulo Usuários do Skype (8,7 Mbytes, grátis em www.skype.com/download.html ), já podiam usar o PC para fazer ... convencionais usando o computador. Chamado de SkypeOut, o serviço foi incluído na recém-lançada versão 1.0 do Skype e antes de usá-lo será preciso pagar uma taxa que, em algumas ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16622.shtml 

20. Folha Online - Informática - Skype terá versão paga que conversa com telefones comuns - 19/05/2004
... 19/05/2004 13h50 Skype terá versão paga que conversa com telefones comuns da Folha Online O Skype, programa de telefonia pela web que permite que internautas conversem entre si gratuitamente, ... um dos criadores do aplicativo nesta quarta-feira. De acordo com Niklas Zennstrom, um dos criadores do Skype e também co-autor do Kazaa, o serviço pago vai conectar os computadores ...
http://www1.folha.uol.com.br/folha/informatica/ult124u16001.shtml 

21. Folha Online - Informática - Programa grava telefonemas no computador - 07/04/2004
... celulares, o computador de mesa também pode ganhar funções de telefonia. Com a instalação do programa gratuito Skype ( www.skype.com ), por exemplo, é possível fazer chamadas ... apenas o custo de uma ligação telefônica local (os pulsos cobrados pela conexão à internet). Para que o Skype funcione, ambos os interlocutores precisam ter esse programa ...
http://www1.folha.uol.com.br/folha/informatica/ult124u15655.shtml 

22. Folha Online - Informática - Skype ganha versão para micros portáteis - 06/04/2004
... 06/04/2004 12h15 Skype ganha versão para micros portáteis da Folha Online O Skype --aplicativo de telefonia via internet que funciona nos mesmos moldes das redes P2P (peer-to-peer), como o ... Segundo o fundador da empresa, Niklas Zennstron --que também foi um dos autores do programa Kazaa-- o novo Skype é um "passo lógico". Ele acredita que o programa pode chamar a ...
http://www1.folha.uol.com.br/folha/informatica/ult124u15642.shtml 

23. Folha Online - Informática - Nova versão do Skype tem teleconferência gratuita - 23/02/2004
... 23/02/2004 16h49 Nova versão do Skype tem teleconferência gratuita da Folha Online Foi lançada nesta segunda-feira a versão 0.97 do Skype --aplicativo de telefonia via internet que funciona ... desenvolve o software, será lançado, ainda neste ano, uma versão "premium" do serviço, com mais recursos. O Skype foi baixado mais de 7 milhões de vezes desde agosto de 2003 e conta ...
http://www1.folha.uol.com.br/folha/informatica/ult124u15247.shtml 

24. Folha Online - Informática - Programa possibilita conversar via internet - 10/12/2003
... falar pelo PC por meio da internet, gastando apenas pulsos locais (ou a banda larga). Uma alternativa é o Skype, desenvolvido por alguns dos criadores do trocador de arquivos ... Ele é interessante por ser gratuito, uma vez que a maioria dos programas do gênero é pago. O usuário do Skype só pode ligar para quem tenha o programa no seu computador. O ...
http://www1.folha.uol.com.br/folha/informatica/ult124u14727.shtml 

25. Folha Online - Informática - Criadores do Kazaa inventam sistema de ligação gratuita pela web - 17/10/2003
... criaram um programa que permite aos internautas fazerem ligações pela web sem gastar nenhum centavo. A Skype , como foi chamada a empresa de Niklas Zennstrom e Janus Friis, lançou ... muito bom semear a desordem com finalidades positivas", disse Zennstrom. "Temos uma grande ambição para a Skype: fazer dela uma empresa mundial de telefonia", revelou o empresário. ...
http://www1.folha.uol.com.br/folha/informatica/ult124u14187.shtml 


Skype ? The Google of VoIP?
Author: Chris Lewis, VoIPAction
Friday, 10 December 2004, 14:01 GMT

2004 has been a stellar year for adoption of Voice Over IP here in the United States as the FCC cleared the way for open competition by ruling that VoIP is not interstate in nature and is subject to Federal jurisdiction for future laws and regulations.

The ruling had it?s opponents of course including the National Telecommunications Cooperative Association (NTCA) who accused the FCC of giving VoIP a "free ride" and an unfair competitive advantage over copper legacy networks operators. A quick check of the NTCA?s web site reveals that they are a non-profit association representing small and rural telephone cooperatives here in the US. More specifically, the NTCA has 557 telcos amongst it?s members.

The fact that telco vested interests are speaking out against VoIP and lobbying Congress shows how seriously they are taking the issue, and so they should.

Skype - the most popular VoIP software in the world ? is here. Already with 38 million downloads (around 5% of all Internet users), Skype is possibly the fastest growing free service ever offered on the web and it has just been bundled with the Kazaa Peer 2 Peer music swapping service that has 170 million users worldwide.

The ?Skype Out? service (you can call non-Skype phone numbers for around 2.2 cents a minute) now has 290,000 paying customers. While this number is tiny in terms of overall telephone penetration, the real marketing power of the Skype business model ? and something that the telco?s cannot match - is it?s viral nature.

People really love something free on the Internet, and the fact that telephone companies have acted as - and been perceived as - utility services for years gives them zero brand equity in fighting off this challenge, in fact it works against them. There is an appeal surrounding Skype that harkens back to the early days of the Internet, a time of technology revolution where traditional services and business models were turned on their heads by ?disruptive? technologies.

The Early Adopter base of Skype were those techies who instinctively understood and grasped the value of breakthrough technologies, they didn?t need to be convinced about Skype through marketing pitches, they just tried it and it worked.

Add to this the following. The company has received funding from Draper Fisher Jurveston, a powerhouse venture capital firm here in Silicon Valley; the software is being enhanced to work on multiple platforms including wireless and PDA technologies; equipment vendors are rushing to introduce telephone handsets that integrate with Skype.

But does Skype have the ability to break through into a market leadership position? After all it?s going up against some very substantial competition in the form of the telcos and cable companies.

Well, yes. Rule One of launching a successful new technology is ?Execute, Then Improve?. It worked for Microsoft and Bill Gates, and it?s working here. We could be seeing another Google in the making.

Chris Lewis is the Founder of VoIPAction.com, an informational web site on VoIP, what it is, how it works, and where to get it.
 


HTC wants Skype for MS smartphone
CBR Online
14 Dec 2004, 09:24 GMT

Smart device manufacturer High Tech Computer Corp has reputedly approached Skype Technologies SA to create a port of its voice over IP software for its range of Windows Mobile-powered smart phones.

^We're interested in dual mode smart phones and would like to discuss with you the possibilities of using Skype smart phone version as our voice over IP application solution," an HTC engineer apparently wrote to Skype in a memo published on the MSMobiles website.

Given that a version of Skype already exists for Windows Mobile Pocket PC, a version for the Windows Mobile Smartphone would appear a likely next step. However, no handsets featuring the platform currently offer the wireless LAN connectivity that make VoIP worthwhile.

This suggests that HTC, which is responsible for the design and manufacture of many of the world's Windows Mobile devices, could be investigating bringing WLAN to its mass-market handsets.

VoIP-enabled mobile handsets are also expected to form an important part of future fixed-to-mobile voice migration initiatives.
 


VoWLAN ou VoWi-FI (Voice over Wi-Fi)
 



Abaixo:

- Visão geral das tendências - Artigo em inglês

 - Voz sobre IP se livra dos fios - Artigo

- Posts de Eduardo Prado no "Novas Tecnologias - Novos Negócios

- Artigos e notícias coletados no Google

- Mais artigos e notícias (enviadas por Eduardo Prado)

 



Voice Over WiFi Mutates
Posted on Monday, February 21 @ 10:59:31 PST by samc

The Voice over WLAN (VoWLAN) market has experienced much hype says a Research and Markets report; "Voice over Wireless LAN: Come On and Feel the Noise".

Much of the interest has surrounded the combination cellular and Wi-Fi handsets, with a vision of the end-user being able to switch seamlessly between cellular and Wireless LAN (WLAN) networks, while maintaining a call.

The VoWLAN market is really divided into four segments at this stage, says the report. The four areas include the following:

(1) VoWLAN handsets for the enterprise,

(2) VoWLAN handsets for the home/SOHO,

(3) soft phones,

(4) and combination cellular/VoWLAN handsets.

Enterprise VoWLAN handsets have been shipping out the door since 2000.
SpectraLink and Symbol have been the leaders in this market for the past few years, selling handsets mainly to the verticals of healthcare, education, retail/warehousing/distribution, and manufacturing.

SpectraLink's phones use proprietary technology to maintain quality of service (QoS) for voice traffic, according to Ben Guderian, director of market strategy and industry relations at SpectraLink.
SpectraLink's phones work with PBX or IP call servers provided by companies such as Cisco Systems and Nortel Networks, which are increasing looking toward VoIP solutions, Guderian said.

SpectraLink plans to replace SVP with 802.11e when the standard is ratified.
QoS is more complex in the enterprise because applications are more varied and the physical scale of WLANs is greater.

Cisco's Wireless IP Phone 7920, interface with 802.11b access points.
With total handset shipments totaling less than 60 thousand in 2003, this market is still a niche market, however.
Factors hindering large volume shipments include the relatively high cost of handsets (generally an ASP of $600), and the lack of standardized QoS and fast roaming.

Currently, there is no QoS standard for 802.11.
But Task Group E (working on the 802.11e QoS amendment) may have a standard ratified by the first half of this year, leading to Wi-Fi Multimedia (WMM) products.
WMM (Wi-Fi Multimedia) is modeled after the IETF's DiffServ architecture, which provides four data-access categories that can be assigned different priorities.

The home market is likely to grow fast as $150 WiFi phones become available.
Similar in size and appearance to cellular handsets, they can be used with $20-$30, VoIP packages for toll-free calling and provide a bundle of additional services like 800 number service, PBX services and multiple party calling.

Dedicated, wireless (WiFi) VoIP phones include; Pulver's Wisp Phone, Senao's SI-7800H and SI-800H Wi-Fi sip phones and ZyXEL VoIP WiFi Phone are offered by services like Broadvoice. A wireless laptop running XTen Soft Phone may also be used.

Verizon signed a multiyear deal with Westell Technologies to sell a phone that integrates a high-speed Internet modem and wireless networking.

Verizon One will integrate several technologies -- including a DSL modem, 802.11g wireless router, 5.8 Ghz cordless telephone and color touch screen -- on a single desktop appliance.
Verizon, will offer it in the first half of this year to customers of its digital subscriber line broadband service. It did not disclose prices.

Verizon said the phone would offer features such as an address book and calendar, e-mail previews, call management and news and weather updates.
It will also work with Verizon's Iobi service, which controls voice mail and e-mails over several devices.

Verizon's VoiceWing VOIP service, for $34.95/month, provides unlimited local and domestic long distance calling.

Cordless phones are also going VoIP.
VTech's ip8100 phone ($119) uses the 5.8GHz band for the cordless phone connection to a base station.
The base station connects via Ethernet to a LAN, router or broadband modem.
It comes with two handsets and can be expanded to four.
It's a cordless VoIP phone that doesn't need WiFi.

Laptop or PocketPC software can also be used for VoIP phone calls, of course.

PhoneScoop has the lowdown on a UMA, WiFi flip phone from Chi Mei.
UMA stands for "Unlicensed Mobile Access".
The BenQ P50, a Windows Mobile Pocket PC, was demoed at CES last month.
It comes pre-loaded with Skype software.
HP's iPAQ h6315, T-Mobile's MDA IV and Motorola's MPx will also offer both WiFi and cellular connections.
Motorola and Skype have partnered for mobile VoIP.

Unlicensed Mobile Access (UMA), provides access to GSM, Bluetooth and 802.11.
By deploying UMA technology, service providers can enable subscribers to roam and handover between cellular networks and public and private unlicensed wireless networks using dual-mode mobile handsets.

Microsoft and Alcatel have created an IPTV partnership.
A satellite dish with an integrated WiMax-fed hotspot for $300? Why not. The manufacturing cost of The Dish receiver is estimated around $90.

 



Voz sobre IP se livra dos fios

Sexta-feira, 15 abril de 2005 - 11:37
 
No San Antonio Community Hospital, a VoIP é a segunda aplicação na lista das que estão sendo implementadas sobre a rede Wi-Fi já existente, logo depois do acesso via computador a registros e raio X de pacientes à beira de leitos e em centros cirúrgicos, explica Irv Hoff, gerente da rede do hospital.
 
Mobilidade real e custos menores foram os principais desafios que Hoff precisou superar em relação às redes Wi-Fi, mas agora ele está convencido de que a tecnologia satisfaz suas necessidades.
 
Alguns detalhes da implementação de VoIP ainda precisam ser solucionados para evitar problemas como queda de ligações entre pontos de acesso ou bloqueio de sinais  devido aos obstáculos dos prédios. "Queremos que a qualidade da chamada seja igual à que você espera de um telefone com fio, tendo em vista que controlamos o ambiente", explica Hoff.
 
Os problemas desse tipo de solução são complexos porque VoIP sobre Wi-Fi reúne as peculiaridades das redes locais wireless (wireless LANs ou WLANs) e telefonia IP. Assim como as WLANs para dados são cada vez mais aceitas, o mesmo acontecerá com VoIP sobre Wi-Fi, prevê Will Stofega, analista da IDC.
 
Mas, para ele, os problemas potenciais de VoIP precisam ser enfrentados antes. "Se há retardo ou perda de pacotes, com VoIP você ouve", diz Stofega. E, à medida que telefones Wi-Fi VoIP proliferarem, as ligações telefônicas vão fomentar a demanda por redes wireless. "Se você dá mobilidade às pessoas na LAN, você tem que aumentar o número de pontos de acesso."
 
Apesar destes problemas, as redes Wi-Fi estão crescendo e as vendas mundiais de equipamentos de infra-estrutura para redes sem fio móveis deverão saltar de cerca de US$ 43 bilhões no ano passado para US$ 49 bilhões no final de 2008, de acordo com a IDC.
 
À medida que os executivos se familiarizarem com o transporte de dados através destas redes, cada vez mais eles irão acrescentar VoIP, diz Stofega. No momento, o uso de VoIP sobre Wi-Fi é muito limitado. Com avanços tecnológicos para facilitar o uso e garantir qualidade de voz, este uso vai aumentar, segundo Stofega.
 
A Airespace (que está sendo adquirida pela Cisco), a Siemens e a Trapeze Networks são algumas das empresas que estão vendendo pontos de acesso e switches capazes de suportar VoIP. De acordo com a Siemens, os principais usuários são hospitais, lojas de varejo, fabricantes e depósitos de mercadorias.
 
Chaves para a implementação
 
Para Hoff, do San Antonio Hospital, o primeiro passo é garantir que os pontos de acesso cubram cada local em que um usuário possa estar. Em seguida, ele precisa assegurar que haja pontos de acesso sobrepostos suficientes para suportar uma provável carga de usuários simultâneos, sem negar serviço a nenhum deles. Hoff usa equipamentos da Trapeze e uma ferramenta que a empresa fornece chamada RingMaster que mapeia prédios e a entrada eficaz de freqüências Wi-Fi através de paredes, chãos, portas e janelas.
 
Esse é um aspecto particularmente importante em hospitais, não só porque são comuns reformas que mudam a localização de paredes, mas também porque algumas destas paredes são blindadas contra raios X e, portanto, também hostis a transmissões Wi-Fi. "Fazemos muita remodelação - novas partições, novos escritórios", diz Hoff. É um processo em andamento, ou seja, à medida que o hospital realiza mudanças, registra-as no RingMaster, que identifica novos pontos cegos. Assim, os pontos de acesso são reconfigurados para contorná-los.
 
O balanço de carga entre pontos de acesso é fundamental para a distribuição eficiente de chamadas, dizem os fornecedores. Pontos de acesso Airespace, por exemplo, distribuem os usuários uniformemente em ambientes onde eles possam estar sob o alcance de diversos dispositivos ao mesmo tempo. Sem este recurso, equipamento do usuário disputaria entrada no ponto de acesso com o sinal mais forte. A Siemens diz que sua próxima leva de dispositivos também terá este recurso.
 
Presumindo que existam pontos de acesso suficientes para garantir cobertura, executivos de rede têm que garantir handoffs rápidos entre os dispositivos à medida que os chamadores entram e saem de alcance em locais diferentes. O switchover tem que levar menos de 50 milissegundos - isso significa que é essencial um projeto de rede cuidadoso. Com voz e dados trafegando na mesma rede, por exemplo, os handoffs podem levar de meio segundo a 10 segundos, com a presença ou ausência de dados na rede afetando o tempo de maneira imprevisível.
 
Além do desempenho da rede, qualquer uso de VoIP sobre Wi-Fi deveria incluir uma avaliação da qualidade da voz. "Você quer estar no meio de uma ligação com um cliente e mal conseguir ouvi-lo?" pergunta Stofega.
 
O futuro do roaming externo
 
Deslocar-se dentro de um prédio pode bastar para a equipe interna de um hospital, mas o pessoal de vendas que viaja pelo país também pode beneficiar-se de telefones wireless VoIP e economizar dinheiro para os clientes, diz Keith Waryas, analista da IDC.
 
O uso de telefones wireless VoIP ou mesmo de um software de softphone VoIP em um laptop transforma hotspots públicos em refúgios para os usuários que não querem gastar minutos em seus celulares onde tarifas mais caras poderiam ser aplicadas, explica Waryas.
 
"A maioria dos usuários corporativos está sendo reembolsada por seus empregadores pelo uso de seus celulares pessoais", diz. Para resolver esse dilema, a empresa designaria um telefone wireless VoIP para usuários que se deslocam e receberia menos relatórios de gastos para reembolso de celular. Uma das limitações expressivas para essa alternativa, no entanto, é o número de hotspots públicos disponíveis hoje, embora esse total esteja aumentando rapidamente.
 
Até mesmo quando existem hotspots públicos suficientes, as corporações não teriam controle sobre o design e o gerenciamento dessas redes públicas, e por isso, a qualidade poderia ser afetada. Além disso, cada usuário teria que transportar dois telefones, um Wi-Fi e outro celular, se quisesse permanecer ao alcance o tempo todo.
 
Visivelmente, porém, os fornecedores de serviços acham que existem clientes interessados em telefones Wi-Fi em número suficiente para justificar o suporte aos novos serviços. A Vonage, fornecedora de serviços VoIP, anunciou recentemente um serviço que suporta telefones WiFi. A Net2Phone está prestes a comercializar serviço similar nos Estados Unidos, após lançá-lo no Canadá.
 
Aliada a parceiros, a Motorola também está testando em campo os primeiros telefones wireless dual-mode, hotspots e PABXs que permitem aos usuários fazer ou receber chamadas em redes Wi-Fi corporativas e continuá-las em redes GSM quando saem do alcance Wi-Fi.
 
Assim, um médico que iniciasse uma conversa no hospital via Wi-Fi poderia sair do prédio, entrar em um carro e partir sem interromper a ligação porque ela seria transferida para uma rede celular.
 
Os sistemas compostos por telefones Motorola híbridos requerem o uso de PABXs Avaya e pontos de acesso da Proxim para coordenar o handoff de chamadas e são apresentados como um meio para as empresas reduzirem os custos de celular. As empresas comprariam os telefones e configurariam contas de celular corporativas, o que lhes permitiriam negociar tarifas mais baixas do que as que seus funcionários possuem individualmente.
 
Para que a solução funcione, no entanto, os telefones da Motorola só têm acesso a redes Wi-Fi específicas que contam com servidores de presença da empresa, capazes de rastrear a localização exata dos usuários.
 
Os fornecedores de serviços, por sua vez, poderiam oferecer um serviço gerenciado baseado nesta tecnologia. Waryas, da IDC, espera que pelo menos uma importante operadora norte-americana anuncie a oferta do serviço em meados desse ano. Isso daria aos usuários transição "sem costura" de celular para Wi-Fi em hotspots públicos.
 
O gerente de telecomunicações de um hospital, que preferiu não se identificar, está cogitando a adoção da tecnologia, mas manifestou preocupação com o sistema de billing. A grande dúvida, segundo ele, é saber como a rede decide qual tecnologia vai usar e se haverá uma tarifa diferenciada para as chamadas recebidas na rede Wi-Fi.
 
Os defensores deste tipo de serviço dizem que as empresas poderão negociar bons acordos para os celulares porque vão precisar de muitos minutos de chamadas. Segundo Waryas, estes serviços vão possibilitar a criação de roteamento menos dispendioso para manter o custo baixo. "Se o billing não é problema, estes serviços dual-mode poderiam acabar com algumas dificuldades de cobertura de Wi-Fi em prédios", acrescenta Waryas. "Quando um usuário entrasse em um ponto sem cobertura em um prédio, a ligação prosseguiria como uma chamada celular em vez de cair", conclui o analista.
 
Sim, nós temos VoIP com Wi-Fi
Ana Paula Oliveira
 
Embora em um ritmo mais lento do que em outros países, o mercado nacional também está seguindo a tendência de aliar as soluções corporativas de voz sobre IP (VoIP) com o uso de redes wireless sem fio, geralmente baseadas na tecnologia Wi-Fi.
 
De acordo com Bernhard Schultze, gerente de mercado corporativo da Nortel, a solução já está disponível para comercialização, embora nenhum contrato ainda tenha sido fechado. "Apesar disso, temos vários clientes interessados e vemos um grande potencial de uso conjunto das tecnologias em empresas das áreas de manufatura, hospitalar e até de hotelaria. Até o fim do ano, veremos as primeiras soluções pontuais e acredito que as empresas de manufatura devem sair na frente", avalia.
 
Para Schultze, a combinação entre VoIP e Wi-Fi não deixa nada a desejar em questões como segurança e qualidade de serviço, itens cruciais para as empresas quando se fala em acesso às redes corporativas de voz e dados. "Em relação à segurança, mesmo quando o usuário acessar a rede utilizando o softphone do laptop ou de um iPAQ em um hotspot público, como em um aeroporto, por exemplo, o software instalado no equipamento vai abrir um canal totalmente seguro, dentro da rede virtual privada (VPN) IP da empresa, ou seja, a solução vai usar a internet como ponto de entrada da VPN mas, a partir daí, o tráfego está isolado e protegido dentro da rede corporativa", explica.
 
Na avaliação do gerente da Nortel, a qualidade do serviço também não é um problema grave quando se usa Wi-Fi. "Os padrões que ainda estão sendo desenvolvidos, como o 802.11c, já contam com recursos como priorização de tráfego de voz dentro da WLAN, o que garantirá a qualidade das chamadas", prevê Schultze.
 
A Cisco, um dos nomes mais citados quando se fala em telefonia e voz sobre IP também conta com a solução integrada e já instalada em pelo menos dois clientes no Brasil. Um deles é a Alcoa, produtora de alumínio que distribuiu iPAQs para operadores do chão-de-fábrica que acompanham a produção das cubas de alumínio.
 
"A função desse profissional é avaliar o equipamento fabricado e ligar para o cliente, que pode estar em qualquer lugar do mundo, passando as especificações do produto. Com a instalação de hotspots dentro da planta, ele avalia o produto e não precisa andar 300 metros para falar no telefone mais próximo. Ele utiliza o iPAQ, com acesso wireless Wi-Fi e entra na rede de VoIP da Alcoa para fazer a chamada", explica Carlos Borges, engenheiro de sistemas da Cisco.
 
Borges também acredita que a área de manufatura será o ambiente fabril que vai impulsionar a adoção da tecnologia.
 
Outra empresa que adotou Wi-Fi para completar sua rede de VoIP, segundo conta Borges, é a Dacasa Financeira, sediada em Vitória, no Espírito Santo.
 
Antes, para se locomover em um prédio de cinco andares, os funcionários andavam com um celular, para onde as chamadas eram desviadas se eles não se encontrassem em sua mesa. "Além de ocupar dois troncos da rede, a empresa pagava pelas ligações recebidas quando as mesmas entravam na rede da operadora móvel. A solução foi instalar antenas, hotspots Wi-Fi e telefones IP sem fio. Assim, a mobilidade está garantida e a chamada não sai da rede IP", detalha o executivo.
 
Para a Cisco, o mercado brasileiro ainda tem que cruzar algumas etapas antes de usar VoIP com Wi-Fi em larga escala. "Ainda temos um grande número de empresas que não oferecem equipamentos móveis aos funcionários como laptops ou handhelds. Essas tecnologias precisam se massificar. Somente a partir desse ponto, a demanda por redes VoIP móveis poderá se intensificar", conclui Borges.
NetworkWorld 

 



"Posts"
 

24/05/2004 - Segunda-feira

 

VoIP, WLAN  e "As Águas de Março" 

Sras e Srs. embora estejamos em Maio queremos relatar que Março foi um mês de muitas surpresas em matéria de VoIP combinado (ou não) com WLAN. 

Veja abaixo uma coletânea variada do Weblog Smart Convergence

0.
Microsoft
 

Will Microsoft Dominate VoIP?
DSL Reports
March 2, 2003

Integrating a skype-like app into the OS...

Business Week argues that while smaller players like Vonage and individuals like Jeff Pulver are getting all the attention, Microsoft is quietly positioning itself to dominate the VoIP industry. By integrating SIP VoIP into the OS, some analysts worry Microsoft could quickly forge the largest VoIP network around, one which doesn't touch the PSTN, and doesn't require regulation. The article hints that the Pulver victory (see our recent interview) - which frees "pure" VoIP providers from regulation - isn't a big deal on its own, but could spell trouble if a larger provider like Microsoft begins to move.

The article suggests that because Windows XP already contains the SIP software, and Microsoft recently unveiled Live Communications Server (LCS) for corporations, it's a quick jump to assume they could dominate the industry. Of course, companies like Cisco, the bells, and numerous others are not Netscape. 

1.
VoWLAN market gains traction
Fierce Wireless


The market for Voice-over-WLAN (VoWLAN) is gaining traction as vendors this year look for the technology to take off with the enterprise market. VoWLAN offers cheap voice coverage for corporate campuses and large facilities, such as factories, college campuses, and hospitals. VoWLAN start-ups, like Vocera, are targeting vertical markets such as healthcare. Network vendors are also now marching into this market. Alcatel and Nortel Networks yesterday launched new VoWLAN products, and both companies also promised to start re-selling WiFi handsets from SpectraLink.

See more ...

Wi-Fi and VoIP: Is sum greater than parts?
Last modified: March 1, 2004, 1:48 PM PST
By Marguerite Reardon
Staff Writer, CNET News.com

Wireless local area networks and Net-based phoning have been among the most talked-about emerging technologies for businesses over the past year, and now, vendors are introducing products they say will help companies combine the two.

"Wi-Fi and VoIP are powerful technologies on their own," said Richard Webb, directing analyst for wireless LANs at Infonetics Research. "But together, they are far more powerful. It's sort of like adding one plus one and getting three."

Equipment vendors have been targeting these markets separately, but so far, adoption has been slow. According to a study Forrester Research conducted, only about 20 percent of the 818 companies Forrester surveyed said they had completed or were in the process of rolling out Wi-Fi or wireless LANs. About 15 percent said they had completed or were in the process of rolling out voice over Internet Protocol systems.

Experts agree that combining these technologies will help push each of them further. As a result, equipment makers are starting to beef up their offerings. On Monday, Alcatel and Nortel Networks, both strong players in the voice market, announced new wireless products.

Alcatel announced that it will resell wireless switches, appliances and access points from start-up Airespace. The products will be marketed and sold under the Alcatel OmniAccess brand. Alcatel said the equipment adheres to the 802.11i security standard the Institute of Electrical and Electronics Engineers ratified, which provides strong encryption for data carried over wireless networks. Alcatel also said the products will support the 802.11a/b/g standards, which promise to improve security and enable higher throughput and VoIP. The IEEE is expected to ratify the 802.11a/b/g standards this summer.

In addition, Alcatel said it plans to start reselling wireless LAN handsets from SpectraLink in October 2004. These handsets are based on the 802.11b standard and will act as extensions of the Alcatel OmniPCX family of IP-PBXs.

Nortel Networks, which started selling its family of wireless switches last year, announced on Monday the 2210 and 2211 wireless handsets. Like Alcatel, the company is partnering with Airespace and SpectraLink for the handset technology.

Experts say the marriage between VoIP and Wi-Fi is a natural one, as companies look for a common infrastructure that will give workers more flexibility in how

they communicate. VoIP over Wi-Fi offers many benefits to corporate users, such as eliminating the need to use valuable cellular airtime within a campus network. What's more, many cellular phones lose their signal when inside steel frame buildings, so Wi-Fi phones would provide better quality of service and reliability. It's especially useful in vertical industries such as health care, where cellular phones can't be used at all, because they interfere with certain machines.

"As companies build out their next-generation IP infrastructures, they want one highly available and secure network for their wired LAN and their wireless LAN," said Brian Witt, director of product marketing for Alcatel. "We can offer them the gear to do this. Voice over wireless LAN will be just one service that runs over this infrastructure."

But in order for VoIP over Wi-Fi to really take off, it will also have to combine cellular technology, said Joel Conover, an analyst at Current Analysis. Motorola has already started talking about delivering handsets that support both cellular and Wi-Fi access. The company is partnering with VoIP gear maker Avaya and Wi-Fi equipment manufacturer Proxim to develop products that combine cellular, VoIP and wireless technology.

Alcatel and Nortel said the handsets they announced Monday will only support Wi-Fi access. 

2. 
Dailywireless

Enterprise VoIP

Tuesday, March 02 @ 00:19:00 PST

Airespace
has signed separate deals for wireless Voice over IP with Alcatel and Nortel for VoIP. SpectraLink is Alcatel's incumbent's OEM partner (see Alcatel Intros WLAN Products and Nortel Touts VOWLAN). 

Spectralink's s340 and s640 Docking Stations
, which were first announced nearly a year ago, act as charging cradles for SpectraLink's e340 and i640 Wi-Fi handsets and add standard desktop telephone features such as a speakerphone, keypad and display. They will ship in April for $299. SpectraLink is also working on a standalone desktop phone that will feature an integrated 802.11 radio. That phone will be designed for places where it's difficult to run Ethernet or telephone wires.

Airespace already has a WLAN handset partnership deal with SpectraLink, which supplies the phones and quality-of-service software that allows voice traffic to be prioritized on an 802.11 network (see Airespace Talks Up VOIP).

Meanwhile Lucent has teamed with Cisco Systems to develop a carrier-class voice over Internet Protocol (VoIP) and multimedia communications solution for mobile service providers. It uses the Cisco MGX 8000 Series Media Gateways to deliver converged IP-based services -- such as VoIP, high-speed data and multimedia communications -- across third-generation (3G) Universal Mobile Telecommunications System (UMTS) and CDMA2000 and CDMA450 mobile networks. "This will enable operators to take advantage of the tremendous revenue potential, and cost savings made possible by IP technology," ," said John Marinho, vice president of offer management with Lucent's Mobility Solutions Group.

Clay Shirky explains it all; "Where Vonage and a number of the other VoIP startups present themselves to the customer as phone companies, emulating the incumbents they are challenging, you can think of Plan B as the Skype plan. Skype isn't taking on the trappings of a phone company; instead, it offers free two-way voice conversations over the internet."

 

"Wi-Fi and VoIP are powerful technologies on their own, but together, they are far more powerful. It's sort of like adding one plus one and getting three, " says Richard Webb at Infonetics Research.

 

But in order for VoIP over Wi-Fi to really take off, it will also have to combine cellular technology, said Joel Conover, an analyst at Current Analysis. Motorola and Nokia have shown handsets that support both cellular and Wi-Fi access. Avaya and Proxim have teamed to develop Proxim's new AP-4000 with Voice over IP features.

There has been an explosion of SIP Products. VoIP operators like Vonage, SIPphone and 8x8, often use ordinary phones. They plug into an adapter than connects to your broadband connection. Nothing is hotter than Mobilized VoIP. "Free" VoIP services include Skype, Pulver's Free World Dialup and Asterisk, an open-source SIP server.

 

Skype, the "free" VoIP client software that runs on PCs and soon PDAs, is creating quite a buzz on community lans. That's partly because it brings "free" voice to users (when both parties are connected using the internet. The other reason that VoIP has become a hot topic on community LANs is because it "breaks" the captive portal model. A wireless phone has no convenient way to display a splash page and its associated legal disclaimer.

 

That disclaimer, it has been believed, helps to remove legal liability from "free" internet providers. Currently, standalone WiFi VoIP phones may not be able to connect or acknowledge the disclaimer. A method to provide that needs to be developed, say some community lan activists.

BOM DIA!


27/DEZ/2003 - Sábado

 

VoWLAN RIDES AGAIN ...

 

Mais 1 da Série Didática de WLAN. Hoje com VoWLAN.
O que é isto? Vejamos então...
Não existe hoje a VoIP (Voice over Internet Protocol) tomando vulto?  
Veja referências recentes de VoIP:

 

O Skype pode ser um fenômeno em VoIP  do site autoral Alice Ramos

 

RBOC VOIP Coming in 2004 do Magazine Board Watch:
SBC Promises VoIP   from DSL Reports
Bells Join VoIP Push  from DSL Reports

 

 

Então ... VoWLAN é Voice over Wireless LAN
Ué... isto é mais complicado que o VoIP que todo mundo está falando agora? Sim, é bem mais complicado pela natureza Wireless no "negócio". 
Imagina juntar os "pacotes" da sua voz digitalizada quando você caminha de um  Access Point  para outro. Não é uma tarefa simples e está sendo bem endereçada. 
Acreditamos - pelo "andar da carruagem" - que em 2004 teremos excelentes notícias neste terreno.

 

VoWLAN vai ser muito interessante no mercado Corporativo principalmente naquelas empresas aonde vc tem uma grande parte dos empregados 80% do seu tempo de trabalho fora das suas mesas como os segmentos de hotel, de hospital, do varejo e de logística para citar alguns. 

 

1. Veja o que já estão pensando ...

 

Este WISP no Reino Unido jjá quer fornecer o serviço de VoWLAN em 2004.

Smart Convergence  on Saturday, November 22, 2003

UK WISP to offer VoIP
Wi-Fi Planet
By Vikki Lipset
November 21, 2003

Patrons of U.K. hotspots will soon be able to make voice calls over public wireless LANs, thanks to a new service from Internet access provider Broadreach Networks.

The service, called ReadytoTalk, won't officially launch until next summer, but Broadreach will do a test run with 40,000 customers in the interim. The voice over IP (VoIP) service will be an add-on to the company's ReadytoSurf hotspot service, which passed the 500,000 user mark this week.


All ReadytoSurf sites will also be ReadytoTalk-enabled, according to Broadreach CEO Magnus McEwen-King. There are currently 129 ReadytoSurf hotspots in coffee shops, retail stores, hotels and other locations across the United Kingdom.

Like ReadytoSurf, the VoIP service will be offered through ISPs and wireless carriers. Users will need to download software, developed by Broadreach, to their laptop or PDA (McEwen-King said the company plans to support all the major operating systems). Pricing for the service is not yet available.

Broadreach has been contemplating a VoIP service for a while, but has been waiting for the right time to enter the market, said McEwen-King. "VoIP has always been a much talked about proposition, but the quality levels have not been there. However, in the last six months, a number of companies have made significant strides in improving both the costs and quality. We feel there's another few months to go, but now is the time to start doing end-user testing with our ISP and mobile phone operator partners."

See the Press Release
 

2.  Enquanto isto fique com esta boa matéria ... 

 

Voice over wireless LAN: Ready or not?

InfoWorld

By  Nancy Gohring  September 12, 2003   

 

Some hurdles remain, but ubiquitous voice communications may be the killer app for wireless LANs

 

WLANs (Wireless LANs) are still in the experimental phase at most companies. Why? Because wireless security standards remain in flux. But a more obvious obstacle to wholehearted adoption is the lack of a compelling need for wireless in the average office, which already has a perfectly functional, wired LAN in place.

 

Well, here’s a thought: How about replacing or supplementing your current phone system with a VoWLAN (Voice over WLAN) system? Just take an ordinary wireless network and add a VoWLAN server along with laptops, PDAs, or newfangled Wi-Fi phones to run the client. Instead of workers wasting time playing phone tag, they can field calls wherever they roam on campus — or even on the road, if there’s a Wi-Fi cloud nearby.

 

VoWLAN is a natural extension of VolP (Voice over Internet Protocol), a technology that has already taken root in enterprise telecommunications. (Today, more IP-based PBXs are sold than conventional models.) Yet VoWLAN presents its own unique QoS (quality of service) challenges relating to fluctuating wireless throughput and roaming among APs (access points), which is why most of today's local wireless voice systems are bundles of proprietary wireless network hardware and software.

 

Industries with highly mobile workers — such as retail, manufacturing and healthcare — can justify the premium for a proprietary network. (One of the most popular solutions, SpectraLink's Wireless Telephone System, costs between $400 and $700 per seat.) Yet the proliferation of Wi-Fi and its increasing reliability opens the possibility of deploying VoWLANs across commodity WLAN setups at much lower costs.

 

Technical hurdles remain. But on the hardware side, at least, everyone seems to be getting in the game. Cisco recently introduced its first VoWLAN handset and a slew of vendors including NEC, Qualcomm, Motorola and Dell promise hybrid phones next year that use both Wi-Fi and mobile phone networks.

 

A Very Local Exchange

 

“It’s just a matter of time before [VoWLAN] catches on in the mainstream enterprise,” says Ben Guderian, director of marketing for SpectraLink. SpectraLink recently introduced a new, lightweight, less rugged handset designed for mainstream enterprise users. Its lowest priced handset costs $399, which compares to around $350 for many desk phones with standard wiring.

 

Proprietary wireless voice vendors such as SpectraLink and Symbol have been among the first to release VoWLAN solutions for commodity wireless infrastructure. But there’s a new breed of VoWLAN provider as well: the softphone developers. These companies, such as TeleSym, IP blue, and VLI have built software that can be loaded onto PDAs or laptops, enabling users to initiate and receive voice calls over WLANs.

 

Basically, VoWLAN systems work in two different ways. Offerings from SpectraLink, Symbol, and Cisco route calls from the phone to the WLAN AP to a VoIP gateway — one that may already be in use to deliver VoIP over the wired network — which translates calls between the IP network and the PBX. That setup allows all regular PBX functions that are available on workers’ wired desk phones to be available on the VoWLAN phones. Calls that are made to phones outside the enterprise go through the PBX to the PSTN (Public Switched Telephone Network).

 

By contrast, softphone developers such as TeleSym provide systems that route calls outside the enterprise over the Internet. In this scenario, road warriors could use the softphone on their PDA or laptop to place calls from a hotel that offers a WLAN. The call could route entirely over the Internet. “Then the call is completely free,” said Raju Gulabani, TeleSym’s CEO.

 

The downside is QoS. Like any voice call that uses the Internet, users can’t control the quality of the connection.

 

Voice, Interrupted

 

Unfortunately, even over the local network, VoWLAN has its shortcomings. The problem is that the 802.11 standards — including those that cover QoS, security, and roaming — simply weren’t designed to support voice.

 

For example, 802.11 entirely lacks a QoS mechanism. This lack means that no special priority is given to voice, so when traffic spikes on the network, dropouts may occur. The IEEE is working on 802.11e, a QoS standard that should be finalized next year. In the meantime, Symbol and SpectraLink have implemented their own proprietary QoS mechanisms through their hardware.

 

But it’s security, or a lack thereof, that’s the biggest deal breaker for VoWLAN today. Enterprises view today's wireless security measures (such as the Wireless Encryption Protocol) as weak, forcing them to opt for wireless VPNs. But VoWLAN offerings that use phones, as opposed to those that use PDAs or laptops, often can’t employ VPNs because the client software usually can’t be loaded onto the phone. (Several vendors, including NEC and Cisco, plan to produce phones next year with VPN support built in.)

 

But using VPNs for voice has other problems. “A VPN tends to encapsulate voice packets, so it obscures them from the network and it can’t discern high priority voice from low priority data,” says Ron Seide, product line manager for Cisco’s wireless networking business unit. In addition, VPN’s cause latency that degrades the quality of voice, says Richard Watson, an engineer at Symbol and director of telephony product marketing.

 

Instead of using VPNs, users can protect against unwanted intruders by putting voice and data on different subnets or VLANs, allowing clients in the voice subnet to communicate only with the telephone gateway, Watson says. With this separation, the widely used encryption and authentication standards offer good enough security, say some vendors. That’s because the threat of eavesdroppers is remote as the listener would have to be within range of the same AP as the phone user. “The joke here is watch out if you have someone walking behind you with an antenna,” says Watson. “It’s an overblown thing.”

 

An added challenge, though, is that encryption and authentication must happen fast enough so that a call isn’t dropped or degraded when a user moves from the coverage area of one AP to the next. The existing 802.11 standard can’t support that handoff fast enough and neither can the security solutions developed by gateway vendors. Even 802.1x, the upgraded security standard in development, won’t work quickly enough. “When standards bodies developed all this, they were more concerned with security on laptops,” says Watson.

 

The handoff between APs should happen in under 50 milliseconds to cleanly support a voice call, says Doug Klein, CTO of Vernier Networks, a security gateway vendor. Vernier’s gateway does the transfer in a matter of a few hundred milliseconds. “It’s not optimum,” admits Klein.

 

As a result, vendors have developed their own fast authentication processes. These generally work by dispensing a certificate to the client proving that it is authenticated, so that when a user moves into range of another AP, the client offers that certificate as proof of authentication.

 

Cisco employs a similar scheme, where one AP is designated as a master AP within a subnet. Rather than require each AP to acquire an encryption key from a backend server as the user roams, the master AP gets a master key and from that, each AP in the subnet spawns a session key. But even Cisco’s solution takes 150 milliseconds.

 

Maybe Next Year

 

The available VoWLAN security solutions aren’t robust enough for many enterprises. “I don’t think it’s likely that we’ll be deploying VoIP on Wi-Fi networks anytime soon,” says Joshua Wright, senior network and security architect for Johnson and Wales University, which already has an extensive WLAN for data users. Current offerings don’t enable the kind of reliability he wants in a voice network.

 

The efficiency of the security and QoS also affects the load that APs can handle. Most AP vendors say each AP can support 10 simultaneous calls, but when pressed, will usually admit to half that number in live deployments. Chris Kozup, META Group's program director of technology research service, says his clients who have tested VoWLAN report on average four or possibly five calls without any data use per AP. “It becomes a problem because there are finite resources here in terms of channel and frequency,” Kozup indicates. “It’s not as easy as lighting up another AP.”

 

New standards, including the faster 802.11g and the QoS specification, 802.11e, should increase the number of users an AP can support. Combined, those upgrades could allow 15 to 25 simultaneous calls, says Cisco's Seide.

 

Ultimately, although the hurdles of deploying a robust VoWLAN are many, they are also surmountable. The key to robust and reliable VoWLAN networks lies in the ability to support security and all capabilities fast enough to hand off between APs seamlessly. As more customers demand support for voice, vendors say they’ll deliver it. “We’ll get around to doing the work that needs to be done,” said Vernier’s Klein.  

 

3. Veja Notícias do IEEE sobre QoS (IEEE 802.11e)

 

Status of Project IEEE 802.11e

MAC Enhancements for Quality of Service
 

The purpose of Task Group E is to: Enhance the current 802.11 MAC to expand support for applications with Quality of Service requirements, and in the capabilities and efficiency of the protocol. 

 

4. Um Trabalho Nosso sobre o Assunto

 

Voz sobre wireless LAN (VoWLAN) do site autoral Alice Ramos 

 

5. Uma Grande Matéria sobre o Assunto

 

VoIP unwired
By Phil Hochmuth
Network World
July 28, 2003
 
Voice and wireless Ethernet might seem an odd mix, but for mobile workers or hard-to-wire areas, it can be the perfect combo.
 
Converged voice/data network projects can be tough, especially if you can't use any wires. That's what Mike Burns, a systems integrator, discovered when a client asked him to provide voice and data services to a gold-mining operation in the middle of a Laotian jungle. Burns faced a sticky situation - literally. 
 
"The ground was mostly mud, so we couldn't bury any cables, and there were no poles where we could hang wire," says Burns, who is president of Nationwide Computer Systems, an ISP and integration firm in Fort Lauderdale, Fla. The solution would obviously be a wireless one: Burns used 802.11b gear to connect 50 IP phones, PCs, a router and satellite dish for the mining camp. The camp, which stretches over a two-mile area, consists of 20 structures for operations, living quarters and offices. 
 
Eu gosto desta figura aqui ...
[Figura grande - Aguarde a carga se a conexão estiver lenta]



Wi-Fi VoIP: Behind the curtain at one medical center
University of Southern California University Hospital uses QoS technology on
a Wi-Fi gateway and at the LAN switch to ensure wireless IP voice calls 
get priority as they crosss the LAN 

 

 


  
1 BOM SÁBADO COM "VOZ DIGITAL" !!!
 


17/NOV/2003 - Segunda-feira

 VoIP & VoWLAN: Um Folhetim sobre estes 02 "moços" .... 
 

Por onde começamos? ... Afinal "são tantas emoções" !
 
1. Definições 
 

VoIP = Voice over Internet Protocol
 
VoWLAN = Voice over Wireless LAN (WLAN)  
 
2. Veja algumas referências de VoWLAN ...  

[a] Wi-Fi Planet
 
VoWLAN: Not Ready for Prime Time

Pocket PCs Dial Up Wireless VoIP

Voice over 802.11: An Emerging Market

Dartmouth Intros Wireless VoIP
 
[b] Outras 

VoIP Unwired
 
Will Wi-Fi lower nurses' blood pressure?
 
Dutch Hospital in Spectralinks
 
[c] Uma do Protocolo SIP 

Carriers Say VOIP & SIP Are Hot  
 
3. Um Texto Nosso 

Voz sobre wireless LAN (VoWLAN) 
Site autoral Alice Ramos
http://www.aliceramos.com/conver/0019.asp
 
Existem problemas? Sim... ainda existem. O site
Unstrung mostra uma dura realidade. Todos esses vendors que estão trabalhando com a tecnologia de VoIP, no padrão 802.11, antes que a especificação de WLAN para suportar voz tenha sido finalizada pelo IEEE, podem ter problemas - isto é, antes que o padrão IEEE 802.11e seja finalizado.  
 
4. Serviços Mundiais de VoIP 

Vonage
 
Net2Phone
 
8x8 Inc
 
Free World Dialup
 
Conexão PC-para-PC: Skype
 
 
5. Super-Informações de VoIP 

Voice over IP and IP Telephony: References
 
Voice Over IP do Dailywireless  
 
7. Wi-Fi Phones 

Palm GPhone
 
Pocket GPhone 2.0
 
Motorola Wi-Fi Phone do Dailywireless
 
Palm VoIP do Dailywireless
 
Free Voice over Wi-Fi do Dailywireless
 
Wi-Fi Phones do Dailywireless
 
Can Wi-Fi Kill Cellular? do Dailywireless
 
Free World Dialup do Dailywireless
 
Handsets Key to VoIP do Dailywireless
 
 
8. PBX IP um importante componente para GERAR RECEITA !!! 

Spectralink's New PBX to VoIP Gateway
  
Start-up unveils four-channel VoIP product
Last modified: October 29, 2003, 10:21 AM PST
By Dawn Kawamoto
Staff Writer, CNET News.com

i2 Telecom announced a four-channel Voice-over-Internet-Protocol product for small businesses on Tuesday, marking the latest product debut for the communications start-up.

The company unveiled its E-VoIP 4000, which aims to lower companies' telephone bills by allowing users to make long-distance and international calls over the Internet. Voice over Internet Protocol (VoIP), a concept that has been hyped for years, is finally gaining momentum as broadband adoption accelerates.

The E-VoIP 4000 has four channels, or the equivalent of four telephone lines, that are used to switch the last leg of callers' calls from the Internet to traditional phone providers.

If a company has multiple offsite locations, an E-VoIP can be placed in each office and the entire call can be placed via the Internet, said Rick Scherle, the company's senior vice president of marketing.  
 
UFA !!! Boa Semana para Todos ... 


From Google:
 

VoWLAN Network Planning and Operations

Published: October 2004
134 Pages
Author: Bruce Hall


Related VoIP Training (Click Here)

Also see: VoWLAN Fundamentals
Broadband Wireless Network Planning Toolbox
and VoWLAN Products and Services


Setembro 08, 2004

Voice over WLAN: Analysis Is The Key To Success

With VoIP comes the notion to run voice on 802.11 wireless LANs (WLANs). But to succeed, Voice over WLAN (VoWLAN) deployments need very careful planning and continuous monitoring.

By Scott Haugdahl, CTO, WildPackets

IP voice applications have already presented new quality of service challenges on wired networks. Data applications could easily tolerate fluctuations in available bandwidth, but the same typical anomalies will drive voice users crazy.

And while most wired LANs have enough bandwidth overhead available so that network engineers can prioritize voice traffic using standard quality of service mechanisms, wireless LANs are bandwidth constrained; that makes the job of offering quality voice services much harder.


However, network engineers can use wireless protocol analyzers to create a better VoIP experience for their users. IMHO, these protocol analyzers should include the following:

VoIP, WLAN and LAN-specific protocol decodes and filters for common problems in these environments;
VoIP call recording and playback, with Mean Opinion Score (MOS) evaluation;
Analytical analysis of packet delay variation and jitter;
Ability to track open calls in real-time and to post closed calls;
Quick drill down to the problem at hand without resorting to complex filtering;
Expert system technology that parses the flood of packet capture information and suggests sources of problems or recommends specific actions.

With these tools in hand, there are two main steps to the VoWLAN rollout process: pre-deployment planning and post-deployment troubleshooting and optimization.

Pre-Deployment

Wireless LAN performance varies widely with the number of clients on the network, their distance from the nearest access point (AP), and the specific environmental characteristics of the coverage area (furniture, building materials, elevator shafts, etc.).

In a voice deployment, the WLAN must support higher and more deterministic bandwidth rates. Ideally, every VoWLAN user should be communicating at the maximum throughput (11Mbps on 802.11b, for example), so the AP placement and configuration in a voice network will be different than it is for a data-only WLAN. Coverage may also be needed in areas normally not occupied by desktop and laptop users.

Protocol analyzers help in planning a VoWLAN deployment because you can use them to:

test the networks throughput;
determine the level of channel interference between access points;
monitor the quality of voice calls at various locations on the network;
and confirm that QoS prioritization polices are working properly.

Here are some pre-deployment questions to resolve and how a protocol analyzer can help answer them:
How many simultaneous voice calls will the WLAN handle? Using a protocol analyzer, you can measure in real-time the quality of voice and quantity of data of a test group of users associated with a given access point.

Investing in a small quantity of wireless VoIP phones (or having a vendor provide evaluation units) will go a long way toward revealing problems early on. You may discover that to maintain good quality, only seven to eight users of full-duplex G.711 VoWLAN phones can supported in one <@BCI>cell<@BCR> area simultaneously.

Where should the access points be placed for optimum voice performance? One of the emerging "best practices" for VoWLAN is to have a higher density of access points and to disable data rates below 11 Mbps, since lower data rates propagate and can reach other access points on the same channel even if they aren't neighbors.

Protocol analyzers can be used to confirm that you have adequate coverage at 11 Mbps in areas where users may roam (including hallways and stairwells) and to ensure that there is no overlapping channel interference from other access points.

Are some segments more robust than others? Why? With a laptop or tablet WLAN protocol analyzer, you can roam your space with ease and measure the signal strength and interference from neighboring channels, from access points on the same channel but some distance away, or simply from other sources of 2.4 GHz RF, such as microwave ovens, cordless phones, Bluetooth, and so on.

Such interference will usually cause a much higher rate of wireless retransmissions and frames with CRC errors.

Post-Deployment

After deployment, the WLAN environment will change constantly depending on which users are doing which activities when, and where they are doing them.

Always keep in mind the mobile aspects of a WLAN -- the network will need ongoing tuning and management to maintain optimum performance. WLAN switch vendors offer ways to tune the network by adjusting AP power levels, prioritizing traffic at the WLAN switch, or implementing QoS at the client and AP.

However, there are a lot of other variables that affect voice performance, such as dropped packets, handoff delays, simultaneous two-way conversations, and security attacks.

Here's a look at how protocol analyzers can assist with identifying and managing these problems.

Dropped Packets

VoIP is susceptible to the same momentary delays and errors that are common to any wireless LAN application, and network performance can vary widely as the user roams or as other users join or leave the network. Such problems quickly degrade voice quality.

With the help of an expert system, the analyzer can determine if any delayed VoIP packets are likely to be dropped by the receiver. This is a somewhat complex operation that basically boils down to analyzing the variability in packet delay and determining which packets may be outside the receiver's jitter buffer for a given codec and arrival rate. This is important, since it is no longer a simple matter of checking for the absence of a packet in the analyzer's capture buffer.

Another technique for mixed LAN/WLAN systems is to put an analyzer in the traffic path on the wired side of the internal network to perform additional call and quality analysis. Many VoIP devices send out periodic reports containing jitter information experienced by the receiver. This way, one can see the real jitter as experienced by the end-nodes at both ends of the conversation without having to place an analyzer at each of those end points.

Hand-Off Delays

Users roaming from one AP's coverage area to another AP's coverage area must be handed off from one AP to the next. When the handoff time is too long, the user can experience clicks, delays in picking up the conversation again, or even a disconnected call.

A protocol analyzer can be used to look at the re-association and recovery of problem calls in real time in order to directly correlate the user experience with actual packet activity and anomalies. The analyzer's VoIP expert system can be an enormous time saver in detected these anomalies.

Simultaneous Conversations

Simultaneous two-way conversations can double the bandwidth requirement for IP phones and thereby slow traffic. Two people won't necessarily be talking at the same time, but any background noise at the listener's location is also transmitted while the other party is talking. Some codec protocols and phones can use noise suppression (which can squelch transmitted packets from a user that is merely listening), but most do not.

Therefore, there is almost always a continuous stream of packets transmitted in both directions during a call.

An analyzer can be used to measure the bandwidth consumed and jitter characteristics of a call (since in essence we are performing full duplex operation on a medium that only allows transmission in one direction at a time), as well as the impact as we add more users.

Security Attacks

As an IP service, VoIP is equally susceptible to security attacks, which can immediately and dramatically affect voice service quality. A VoIP analyzer built on a proven core of protocol analysis and expert system technology can help identify these attacks by triggering events on suspect data such as a worm or unexpected spike in response time or throughput.

Even though VoIP traffic on wireless networks should be encrypted, it's still possible to analyze the traffic by looking for problems such as congestion, CRC errors, wireless retransmissions, frequent drops in wireless data rates, and frame arrival rates (to and from the physical address of the VoWLAN phone).

For VoIP phones that use a static WEP key, network engineers can obtain the key from an administrator and plug it into their analyzer to fully decode all seven layers of protocols.

Conclusion

The number of variables to manage in a VoWLAN application can be daunting, but they're by no means insurmountable. Properly armed with the right protocol analysis tools along with an understanding of VoIP protocols and WLAN anomalies, network engineers can go far to ensure a relatively trouble-free deployment of voice over wireless LAN.
--------------------------------------------------------------------------------

Scott Haugdahl is the chief technology officer at WildPackets where he developed the expert system for the AiroPeek NX 802.11 wireless analyzer. He has more then 20 years of experience in the networking industry and is author of the book "Network Analysis and Troubleshooting." WildPackets, as you either knew or gleaned from his vendor-neutral article, makes network management tools.
 



VoWLAN Heats Up

By Vikki Lipset

03/03/2004

In what could be a big boost for the growing voice over wireless LAN (VoWLAN) market, Nortel Networks (Quote, Chart) and Alcatel (Quote, Chart) both announced offerings this week that add voice capabilities to their WLAN product lines.

The companies will resell Wi-Fi handsets, access points (AP) and switches from SpectraLink (Quote, Chart) and Airespace. Both Nortel and Alcatel say their versions bring something extra to the table.

"It's their hardware, but our special sauce," said Diane Schmidt, director of marketing for Nortel's WLAN portfolio, of the company's new Adaptive WLAN deployment solution, which is comprised of a security switch and access ports that the company says are optimized for VoWLAN.

She pointed to the ability to monitor and control the radio frequency domain as an example. This is key for customers who are looking at real-time applications such as wireless IP telephony and need nonstop coverage over their WLAN, she said.

"If there's a gap in coverage due to some interference or an AP drops out for some reason, because we have control over what happens across the air, we're able to transfer those connections to a device that can handle them, so users won't experience any downtime."

Nortel is also offering additional security features. "We're bringing the capabilities of our security switch -- things like rogue access point detection, support for VPNs -- into this solution as well," Schmidt noted.

"We've brought this airtight security into a realm that's notoriously porous," added Nortel spokesman Pat Cooper.

The Adaptive WLAN package will be available next month. It includes the 2230 (a/b/g) and 2231 (b/g) Access Ports ($599 and $499 respectively) and the 2270 Security Switch (starting at $10,999). The new Nortel VoWLAN products, which include the 2210 and 2211 handsets ($695 and $890 respectively), the WLAN IP Telephony Manager 2245 ($2500) and the WLAN Application Gateway 2246 (starting at $1600), are expected to be available in May.

Meanwhile, Alcatel is offering APs, switches and appliances under the OmniAccess name. OmniAccess 4000 wireless switches start $8,250, OmniAccess 4100 wireless appliances start at $13,685 and OmniAccess 1200 Access Points start at $400.

The company will introduce its version of SpectraLink's wireless handsets, branded as Mobile IP Touch 300 and 600, in September. The phones will work with Alcatel's OmniPCX family of IP-PBX systems.
 



Talking about Securing VoWLAN

By Eric Griffith

05

Embracing voice over IP (VoIP) as the hot new thing in LANs in general -- and wireless LANs in particular -- is not exactly news these days. VoIP is the buzzword of the moment, so it's no surprise when a company like Aruba Networks says it's going to have a "full solution for VoIP in the enterprise."

The difference with Aruba is, they've got partners like SpectraLink (Quote, Chart), Avaya (which rebrands SpectraLink phones), voice-badge maker Vocera, and soft-phone designer Telesym -- names that encompass almost all the major players in Voice over WLAN (VoWLAN). SpectraLink alone held 60% of the global market for VoWLAN products in the year 2003 according to Synergy Research Group. The nearest rival, Symbol, provides about 7% of the world's VoWLAN products.

Aruba also says it will differentiate its VoWLAN support from other switch vendors by concentrating on security.

"There's a huge security hole for voice," says Keerti Melkote, Aruba's co-founder and vice president of product marketing. "Handsets and the technology today are a generation behind the state of the art -- the handsets mostly use MAC address (define) authentication and WEP (define). Static WEP is weak and can be broken and using a MAC address [means] that once that address is admitted, it can go wherever. Spoof that and it can send non-voice packets into the network" to cause a disruption.

Aruba will also be doing some new radio frequency (RF) management to reserve bandwidth and perform load balancing for calls at the access point (AP), all for voice traffic.

The Aruba switch will be able to make a "virtual AP in the air for voice, and operate it with specific power management profiles that are custom built for voice," says Melkote. This profile will take into consideration that phones aren't connected to the network at all times, unlike most WLAN data devices. By contrast, Meru Networks, a switch competitor of Aruba's, recently announced a proprietary solution involving the licensing of firmware to Wi-Fi handset vendors to do the same thing. Meru's switch system has been previously tested as interoperable with Symbol and Vocera products.

Melkote says the Aruba 5000 Switch could handle 5000 calls simultaneously, with a varying number of calls per AP depending on the type of VoWLAN clients due to the codecs and compression schemes used by each of its partners.

Aruba is breaking its voice support into three separate phases. The first is simply to have interoperability with its announced partners; for example the switch will support SpectraLink's Voice Priority Protocol. Phase 2 will include using standards such as Quality of Service from the proposed 802.11e standard and fast-hand off from the 802.11r standard announced at the last IEEE (define) meeting of the 802.11 Working Group. Aruba also plans to support the Session Initiation Protocol (SIP). Phase 3 is well down the road: they plan to offer seamless handoff from cellular to Wi-Fi networks.

Aruba is demonstrating its VoWLAN solution with SpectraLink in London this week at the Wireless LAN show.


VoWLAN: The Wireless Voice Future is Here ... Almost
June 14, 2004
By Beth Cohen

Chris Taylor, Telecommunications Manager, Metro Toronto Convention Centre had a serious problem. His mission critical Nortel "Companion" 900Mz phone system was no longer supported and he needed a replacement system double quick. With 2 million square feet of open exhibition space spread over two buildings, he needed a communications system that provided roaming and instant communications, an open flexible data network, and a minimum of wires. A year ago, he started looking at wireless networking combined with VoIP (Voice over IP) or VoWLAN (Voice over IP over Wireless) as part of the total networking solution. As Taylor put it, "My three goals were to provide wireless data networking for exhibitors, create a corporate profit center by selling services to the exhibitors, and meet employee data/telecommunications needs. The combination of VoIP and wireless networking fit the bill exactly."

With 55 million lines and 15% of the voice market, VoIP is an established and rapidly maturing technology. It has been proven to be less expensive to install and maintain; the core equipment is comparable in cost to traditional voice, and it offers many more integration options. Wireless technology is also rapidly maturing, so the next obvious step is to deploy a converged technology. Until a few months ago, the converged technology suffered from proprietary equipment, weak security, and a lack of scalable network management tools: It was not quite ready for prime time. All that has changed in the past year. The VoWLAN landscape is rapidly changing with evolving standards, new equipment, and finally some good management tools. Let us look at some of the issues that were plaguing VoWLAN and how the fledgling industry is successfully addressing them.

Approaching Technological Liftoff
According to Bob Myers, CTO and co-founder of Chantry Networks, a company that develops wireless network management systems, VoWLAN is growing rapidly in certain vertical industries like health care, hospitality, retail and manufacturing. Industries where the flexibility, combined voice and data requirements are so compelling that they are willing to forgo the current lack of handset hardware, network management tools and poorly addressed security, standards, and QoS (Quality of Service) issues.

Part of the problem is that wireless is a contention media -- the users share the available bandwidth -- so wireless will always have overhead issues and more complex management requirements. Another overlooked issue is how to determine good coverage. In an open field, coverage is easy to determine, but most IT people don't have the specialized knowledge required to plan an installation for a complex environment like a hospital, with all its attendant equipment and building structures.

Myers notes, "Health care's transition to VoWLAN came about because they had widely deployed 802.11 so they were already comfortable with the technology. The hospitality and retail sectors both have a widely dispersed work force that needs to be in constant communication. Both industries were previously using the 900Mz Walkie-Talkie systems, so conversion to VoWLAN was a natural next step. Beyond those specific industries, uptake has been slow because of the perceived security issues and lake of management tools." Recently, there has been a major change in perception as companies discover the benefits of increased flexibility, the improved security standards, and the always popular, substantially lower operational costs.

Wireless Network Management
A critical component to the success of VoWLAN is sophisticated wireless network management tools. As Myers puts it, "Unlike all previous computer technology, wireless networking, wireless came back into the enterprise from the SOHO and home markets. With a three node network, you don't need management tools." When rolling out enterprise wide wireless, especially VoIP, the need for prioritized data streams, transparent access point handoffs, and seamless security are essential. Chantry offers a management package that is designed to specifically address these issues. Other companies, like Avaya and Cisco who are heavily invested in developing this market, are also working to develop new tools.

Continued on Page 2: What Else is There to Think About?

QoS (Quality of Service) and Reliability
Wireless service quality is technologically a step 10 years backwards. For data packet delivery, companies are willing to trade mobility and reduced costs for reliability, but voice packets are more sensitive to perceptible service degradation. As Myers puts it, "You really need to have a max of 150ms to make sure users are not bothered by QoS issues when you are using a VoIP system. Cellular has gotten people used to a lower QoS compared to traditional voice, but not entirely."

To make matters worse, the WME (Wireless Multimedia Extensions) 802.11e wireless QoS standard will not be ratified until the end of 2004 or early 2005. Most wireless equipment has not yet incorporated any QoS because they are waiting for the emerging standards. Because this is such a critical piece for a successful VoWLAN deployment, some companies are implementing a subset of 802.11e. Another gotcha is that while 802.11b officially delivers 11MB with QoS, the actual useable bandwidth is really closer to 6MB. Remember that 6MB is shared by anyone on the access point. VoIP has a tendency to have small packets with a large overhead. With 10 to 15 VoIP users you are quickly down to unacceptable modem-level data rates. The reality is that with most wireless equipment, planners should expect 6-7 voice calls maximum per channel. With Chandra's priority queuing and predictive handoffs, they can support up to 15 voice streams in addition to a small amount of data traffic. By limiting the number of voice calls on a single access point, the software can maintain the required QoS.

Security
Wireless security is finally improving with the newer WPA and WPA2 standards, but these emerging standards have not been fully adopted into the VoWLAN equipment yet. 802.11r is a brand new IEEE taskforce created specifically to address VoWLAN security issues. Expect to see handsets incorporating the improved security standards in 6 to 8 months, and new standards in this area in a year or so. According to Myers, part of the problem is the need to re-authenticate every time users move between access points. Session switching can cause unacceptably high delays (up to 500ms) or dropped calls. Obviously the re-authentication process is in direct conflict with the QoS requirements of maintaining the call data stream. Chantry has incorporated a virtual network service that preloads the VoIP session security at the backend as the user roams the network so the call session is transparently switched to the new access point minimizing signal delay.

Staffing and Operational Issues
Unless you were a tiny company that had an IT generalist, the data and telecom support staff have, until recently, not needed to learn each other's methodologies and equipment. The current trend is to merge the support functions and staff for more efficient operations, but there is still a time lag in training and operational efficiencies, as the staff learn the new equipment and procedures.

Hardware What Hardware?
Currently there are two main companies in the VoWLAN handset market, Vocera and SpectraLink. SpectraLink owns 75% of the total handset market and the majority of the health care market with systems in 1600 hospitals nationwide. Vocera is startup breaking into retail and health care. Because they were first to market, neither of these are standards based systems. Both Cisco and Symbol (the people who invented barcode scanners) have handsets as well. According to Chris Taylor, Symbol has recently dropped the VoWLAN line to focus on their core market. All the products suffer from short battery life and reliability problems. As PoE (Power over Ethernet), standards and cellphone technology is incorporated, expect to see a plethora of better handsets within the next few months.

Are We There Yet?
How is Chris Taylor doing with his VoWLAN system? He reports that they have had the beta system in place since January. They are planning a full rollout to completely replace the old "Companion" system by September. "The staff loves it. The voice quality is good and roaming is completely transparent. Just make sure all the vendors' equipment is compatible and integrated. That was the key to success for our installation."

Should you be seriously considering Voice over IP over wireless LAN solutions today? Well yes and no. Unless you are in the health care, manufacturing, or retail industries where the ROI is especially compelling, the technology is still not quite ready to be heard yet. With the maturing of both the VoIP and wireless technologies, on the surface merging the two emerging technologies might seem to be a terrific idea. However, security issues, poor quality equipment, and bandwidth prioritization considerations point to a technology that is still too immature for anybody to deploy unless they are ready to put up with the bleeding edge phase of the innovation curve. In the next 8 to 12 month there will be numerous new products that will be addressing these and other issues as many innovative technology companies work on solving the problems. Once the issues have been properly addressed and the standards settle down, VoWLAN with its potential to merge data, voice and mobility into one neat package, promises to be something that could transform how companies do business.

--------------------------------------------------------------------------------
Beth Cohen is president of Luth Computer Specialists, Inc., a consulting practice specializing in IT infrastructure for smaller companies. She has been in the trenches supporting company IT infrastructure for over 20 years in different industries including manufacturing, architecture, construction, engineering, software, telecommunications, and research. She is available for consulting to help your company identify the right IT infrastructure to meet your business objectives.


Sugestões enviadas por Eduardo Prado:

Voice on WLAN trials 1: It works!
TechWorld
By David Newman, Network World
07 February 2005

Part 01

Aruba wins - but not everyone entered...

VOIP should be an easy fit for wireless LANs, but mixing the two technologies today is difficult. Despite VOIP's low-bandwidth profile, even a small amount of data traffic on the same network can lead to seriously degraded audio quality and dropped calls, even with QoS features enabled.

That's the major conclusion of our first-ever assessment of VOIP capability in WLAN systems. Over the course of three months we tested WLAN switches and access points from Aruba, Chantry (now acquired by Siemens), Cisco and Colubris. in terms of audio quality, QoS enforcement, roaming capabilities, and system features. The Cisco system, is the company's own product, built around its Catalyst switches, rather than the switch system it is buying in, with vendor Airespace.

Other vendors, including Airespace, Meru and Trapeze, declined to participate.

Among our major findings:

(1) With QoS enforcement enabled, the products delivered near-toll-quality ("nearly as good as wired telephones") audio, provided there is only voice traffic on the network. Unfortunately, this situation is not likely in practice, as companies move toward converged voice-data networks.

(2) When voice traffic had to contend for bandwidth (even with a little data traffic), dropped calls were common and audio quality on the remaining calls was poor in many cases - and this was with QoS enforcement enabled.

(3) With data traffic present, roaming from one access point to another took anywhere from 0.5 to 10 seconds - in cases where roaming succeeded at all. These long delays and dropped calls made roaming practically impossible with some vendors' gear.


While some products struggled mightily in our tests, Aruba's A2400 and A800 switches and A61 access points were consistently strong performers. The Aruba products posted generally excellent numbers, regardless of how much voice or data traffic was thrown at them. Aruba's gear just worked, earning it the Clear Choice Award.

Two issues confounded other vendors. First, when handling voice and data traffic on the same network, vendors need to pay attention to metrics such as delay and jitter rather than forwarding rates.

Many vendors are only just beginning to tune their products for voice/data convergence, even though some have touted that capability for 18 months or more. However, it's still relatively early days for VOIP over WLANs. Test tools that accurately measure these metrics on WLANs are only just beginning to appear (the VeriWave instruments we used were developed for this test, and the company launched its Wi-Fi Traffic Generator at Wi-Fi Planet in November). This test is among the first to measure audio quality, delay and jitter in a methodical way.

Second, the emerging 802.11e standard for QoS on WLANs might bring some relief. The 802.11e specification wasn't yet ratified when we began this project, so by definition all QoS methods were nonstandard. Companies might want to wait until the new 802.11e specification and products based on it are more mature and fully tested.

How to measure quality

Our tests sought to answer a simple question: How does a VOIP over WLAN system sound?

To find out, we worked with VeriWave, a start-up that makes WLAN test and measurement equipment. VeriWave developed a new application, the VOIP over WLAN Analysis Test Suite, especially for our test.

In addition to collecting delay and jitter statistics, VeriWave's test suite and TestPoint hardware let us measure R-value, an ITU specification (G.107) for determining call quality. R-value is an objective measurement, computed directly from measurements of packet loss, jitter and delay. While R-value is objective, it has a strong correlation to the subjective Mean opinion score method in ITU standard P.80 (see R-value ratings).

R-value ratings
An ITU specification that determines call quality, R-value measures packet loss, jitter and delay.

We measured voice call quality with up to 14 handsets and an H.323 call server from SpectraLink, a maker of 802.11 handsets. We measured audio quality with up to seven concurrent calls, and in some events configured the VeriWave TestPoint boxes to offer background data. For each system tested, we checked call quality with QoS disabled, then enabled.

Results in Brief
Over the next three days, we will feature detailed commentary on quality of service, roaming and architecture issues. Here is a brief summary of the results for the four systems we tested.

Aruba Networks
A2400, A800 switches, A61 access point . Overall rating 4.58
Cost: $8,780 as tested.
Pros: Outstanding voice prioritisation capabilities; rich set of QoS and radio frequency management features.
Con: Some call drops in most stressful test case.

Cisco
WLSM Overall rating 3.53
Cost:$51,978 as tested.
Pros: Highly scalable, rich set of routing and switching functions.
Cons: Doesn?t protect voice traffic under most stressful test case; doesn?t dynamically adjust to changes in radio frequency environment; pricey.

Colubris Networks
CN1250 Overall rating 3.0
Cost: $1,800 as tested; access point, $500.
Pro: Powerful and intuitive user interface.
Con: Limited prioritisation of voice traffic.

Chantry Networks (now part of Siemens)
BeaconMaster Overall rating 2.4
Cost: $9,180 as tested.
Pro: Supports Open Shortest Path First routing.
Cons: Dropped calls in six- and seven-call cases; poor voice quality in the presence of data; no contingency for the loss of power.

Conclusions: don't mix voice and data unless the system can handle it
It's possible that overall products may improve when more of them support the 802.11e QoS standard (read more here). All the vendors said it was early in the evolution of VOIP over wireless, and our test results show there is certainly room for improvement. For network managers looking to deploy VOIP on WLANs in the near future, there are three choices:

make very few calls;

don't ever send data;

or look for equipment - such as Aruba's - that handles time-sensitive traffic in a timely way.

Tomorrow: Quality of Service in detail.
 


Wi-Fi phones don't add up to much
By Ben Charny
http://news.com.com/Wi-Fi+phones+dont+add+up+to+much/2100-7351_3-5566708.html
Mon Feb 07 16:25:00 PST 2005

A new study suggests it will be a number of years before Wi-Fi phones, supposedly a revolutionary telephone technology, manage to fulfill expectations.

Analysts at Infonetics Research say portable phones using Wi-Fi, the popular technology that creates 300-foot zones of high-speed wireless connectivity, are taking hold in hospitals and businesses, but worldwide sales were negligible last year.

The results are disappointing. After years in development, the much-anticipated devices were supposed to take off in 2004. But with just 113,000 such handsets sold last year, or $45 million in total sales, it's apparent the prognosticators were wrong. Rather, the sales "represent a market at its birth," as Infonetics analysts put it.

Wi-Fi phones combine two very hot and potent technologies--Wi-Fi and voice over Internet Protocol (VoIP) software, which lets Internet connections double as extremely inexpensive phone lines. Typically, VoIP subscribers use a wired phone line, whether a single home phone or any number of phones in an office setting. But many service providers see an opportunity to create wireless versions of their services using Wi-Fi. Introducing the appropriate VoIP services and technology could turn hot spots into giant phone booths.

But it could take at least until 2009 before the cost of Wi-Fi phones drops enough for a mass market breakthrough, according to Infonetics.

"Voice over wireless Internet devices have the potential to be a hugely disruptive technology," Richard Webb, Infonetics directing analyst said a statement. "As VoIP goes wireless, this will present a challenge not only to fixed line operators, but to mobile operators."

Copyright ©1995-2005 CNET Networks, Inc. All rights reserved.
 


MOBILE VoIP IS GOING TO CHANGE THE TELCO INDUSTRY
Fierce Wireless

Mobile VoIP is dramatically altering the telecommunications industry, according to research firm ON World. There are three developments combining to transform the telecom landscape: Low-powered single-chip radios with integrated protocol stacks; the adoption of standards such as SIP; and the promise of affordable flat rate roaming. There are already more than 400 VoIP service providers in North America.

More ...

SAN DIEGO, Feb. 8 /PRNewswire/ -- Voice over Internet protocol for mobile devices (mobile VOIP) is dramatically altering the telecommunications industry, according to research firm ON World

"As network operators continue to embrace VOIP and enterprises continue to deploy WiFi networks, mobile devices that combine the advantages of both have emerged," says Mareca Hatler, ON World's Director of Research. "Low powered single chip radios with integrated protocol stacks, the adoption of standards such as SIP, and the promise of affordable flat rate roaming are setting the stage for a telecom transformation."
Mobile VOIP Service Providers
With more than 400 VOIP service providers in North America alone, pioneer service providers such as Vonage, BroadVoice and Net2Phone are offering Voice over WiFi (VoWiFi) handsets as a way to differentiate their offerings and encourage more subscriber loyalty.
VoWiFi handsets are like IP based cordless phones that can be used in the home, office and any Wi-Fi network such as hotspots. Business users benefit by having a mobile inter-office phone that is low cost, can go wherever they go, make calls to anywhere in the world, and pay no roaming charges.
Roaming: A Key Enabler
For most users, the ideal mobile device is capable of dual mode voice operation (cellular + VoWiFi). As mobile operators continue to offer Wi-Fi enabled smart phones, ON World predicts that a large percentage of these will also support VOIP. Eventually, this device will roam seamlessly from cell to cell, WLAN to WLAN and cell to WLAN.
"Widespread adoption of mobile VOIP has reached an inflection point which is the lack of roaming solutions," says Mareca Hatler, ON World's Director of Research. "Competitors in this landscape are battling the roaming standards problem on several fronts: development of roaming standards, creation of roaming networks and establishment of roaming alliances."
ON World's recently published report, "Mobile VOIP Competitive Landscape 2005," features Competitor Assessment Grids on 19 companies, actionable competitive intelligence on six market segments and 28 in-depth profiles. For more information, go to: http://www.onworld.com/.

About ON World Inc.:
ON World Inc. provides world class business intelligence on emerging wireless markets. Customers include Fortune 1000 companies, service providers, venture capitalists, and startups worldwide.
For further information please contact Mareca Hatler of ON World, +1-888-312-2619 ext. 12, research@onworld.com.
Quelle: ON World
 



I AM TALKING A LOT ABOUT THAT ... VoWiFi to grow dramatically

Fierce Wireless

VoWLAN is steadily spreading through the enterprise sector, and a recent report says that the technology will see even more robust growth over the next four years. Infonetics Research's latest report says that 113,000 WiFi VoIP handsets were sold world-wide in 2004, bringing in $45 million. Infonetics estimates that global dual-mode WiFi/cellular handset revenue reached $6.6 million in 2004 with more than 8,000 handsets sold. We should note, though, that dual-mode WiFi/cellular handsets were commercially available only in the fourth quarter of 2004.

Both revenue and the number of handsets sold are projected to grow "dramatically" by 2009 as more enterprises offer employees flexible mobile access over different forms of wireless networks. Even though WiFi VoIP handsets currently represent only a small market, this market has "great potential across several market segments," Infonetics stated. Early adopters in the enterprise space will be in the logistics and healthcare verticals, where VoWLAN is already has some momentum. It will become even more wide-spread as both VoIP and WLAN adoption continues.

There is also potential for "enormous growth in the consumer space," as broadband service providers offer both VoIP services and wireless gateways bundled with a broadband connection. Infonetics' Richard Webb says that "voice over wireless internet devices have the potential to be a hugely disruptive technology, too... The traditional model of time and distance-based pricing for voice calls will be eroded by VoIP, and as VoIP goes wireless this will present a challenge not only to fixed line operators, but to mobile operators as well."

More ...

Voice over Wi-Fi raises the volume
Robert Jaques, vnunet.com 08 Feb 2005

Dramatic growth for voice over wireless Lans predicted

Business uptake of voice over wireless Lans is slowly but steadily ramping up, with newly published research predicting that the technology will enjoy strong growth during the next four years.

According to Infonetics Research's latest report, worldwide Wi-Fi VoIP handset sales clocked up $45m in 2004 with 113,000 units shipped.

The analyst firm estimates that global dual-mode Wi-Fi/cellular handset revenue hit $6.6m in 2004, and units totalled more than 8,000. The report noted that units were only commercially available in the fourth quarter of 2004, so this represents a market at its birth.

Revenue and units are projected to grow "dramatically" by 2009 as enterprises take advantage of the opportunity to offer employees flexible mobile access over different forms of wireless networks.

Wi-Fi VoIP handsets represent a fairly small market currently, but one with "great potential across several market segments", Infonetics stated.

Primary adoption is expected in the enterprise space, in logistics and healthcare verticals in particular, where voice over wireless Lan is already gaining momentum but will become more widespread as both VoIP and wireless Lan adoption continue.

Infonetics added that there is potential for "enormous growth in the consumer space" as broadband service providers offer both VoIP services and wireless gateways bundled with a broadband connection.

"Wi-Fi capability will eventually become a common feature in cellphones, just as it is becoming standard in laptops today, giving mobile operators a big opportunity with Wi-Fi voice," said Richard Webb, directing analyst for Infonetics and author of the report.

"But voice over wireless internet devices have the potential to be a hugely disruptive technology, too. One big factor is the low cost of calling, especially long distance, overseas and during peak hours.

"The traditional model of time and distance-based pricing for voice calls will be eroded by VoIP, and as VoIP goes wireless this will present a challenge not only to fixed line operators, but to mobile operators as well."

Webb added that there are technical issues to be worked through before wireless internet calling becomes commercially viable.

Areas that remain to be addressed include quality of service, roaming across different wireless platforms, and the relatively short range of Wi-Fi signals.
 

Voice over WLAN (VoWLAN)

 



 

24/05/2004 - Segunda-feira

 

VoIP, WLAN  e "As Águas de Março" 

Sras e Srs. embora estejamos em Maio queremos relatar que Março foi um mês de muitas surpresas em matéria de VoIP combinado (ou não) com WLAN. 

Veja abaixo uma coletânea variada do Weblog Smart Convergence

0.
Microsoft
 

Will Microsoft Dominate VoIP?
DSL Reports
March 2, 2003

Integrating a skype-like app into the OS...

Business Week argues that while smaller players like Vonage and individuals like Jeff Pulver are getting all the attention, Microsoft is quietly positioning itself to dominate the VoIP industry. By integrating SIP VoIP into the OS, some analysts worry Microsoft could quickly forge the largest VoIP network around, one which doesn't touch the PSTN, and doesn't require regulation. The article hints that the Pulver victory (see our recent interview) - which frees "pure" VoIP providers from regulation - isn't a big deal on its own, but could spell trouble if a larger provider like Microsoft begins to move.

The article suggests that because Windows XP already contains the SIP software, and Microsoft recently unveiled Live Communications Server (LCS) for corporations, it's a quick jump to assume they could dominate the industry. Of course, companies like Cisco, the bells, and numerous others are not Netscape. 

1.
VoWLAN market gains traction
Fierce Wireless


The market for Voice-over-WLAN (VoWLAN) is gaining traction as vendors this year look for the technology to take off with the enterprise market. VoWLAN offers cheap voice coverage for corporate campuses and large facilities, such as factories, college campuses, and hospitals. VoWLAN start-ups, like Vocera, are targeting vertical markets such as healthcare. Network vendors are also now marching into this market. Alcatel and Nortel Networks yesterday launched new VoWLAN products, and both companies also promised to start re-selling WiFi handsets from SpectraLink.

See more ...

Wi-Fi and VoIP: Is sum greater than parts?
Last modified: March 1, 2004, 1:48 PM PST
By Marguerite Reardon
Staff Writer, CNET News.com

Wireless local area networks and Net-based phoning have been among the most talked-about emerging technologies for businesses over the past year, and now, vendors are introducing products they say will help companies combine the two.

"Wi-Fi and VoIP are powerful technologies on their own," said Richard Webb, directing analyst for wireless LANs at Infonetics Research. "But together, they are far more powerful. It's sort of like adding one plus one and getting three."

Equipment vendors have been targeting these markets separately, but so far, adoption has been slow. According to a study Forrester Research conducted, only about 20 percent of the 818 companies Forrester surveyed said they had completed or were in the process of rolling out Wi-Fi or wireless LANs. About 15 percent said they had completed or were in the process of rolling out voice over Internet Protocol systems.

Experts agree that combining these technologies will help push each of them further. As a result, equipment makers are starting to beef up their offerings. On Monday, Alcatel and Nortel Networks, both strong players in the voice market, announced new wireless products.

Alcatel announced that it will resell wireless switches, appliances and access points from start-up Airespace. The products will be marketed and sold under the Alcatel OmniAccess brand. Alcatel said the equipment adheres to the 802.11i security standard the Institute of Electrical and Electronics Engineers ratified, which provides strong encryption for data carried over wireless networks. Alcatel also said the products will support the 802.11a/b/g standards, which promise to improve security and enable higher throughput and VoIP. The IEEE is expected to ratify the 802.11a/b/g standards this summer.

In addition, Alcatel said it plans to start reselling wireless LAN handsets from SpectraLink in October 2004. These handsets are based on the 802.11b standard and will act as extensions of the Alcatel OmniPCX family of IP-PBXs.

Nortel Networks, which started selling its family of wireless switches last year, announced on Monday the 2210 and 2211 wireless handsets. Like Alcatel, the company is partnering with Airespace and SpectraLink for the handset technology.

Experts say the marriage between VoIP and Wi-Fi is a natural one, as companies look for a common infrastructure that will give workers more flexibility in how

they communicate. VoIP over Wi-Fi offers many benefits to corporate users, such as eliminating the need to use valuable cellular airtime within a campus network. What's more, many cellular phones lose their signal when inside steel frame buildings, so Wi-Fi phones would provide better quality of service and reliability. It's especially useful in vertical industries such as health care, where cellular phones can't be used at all, because they interfere with certain machines.

"As companies build out their next-generation IP infrastructures, they want one highly available and secure network for their wired LAN and their wireless LAN," said Brian Witt, director of product marketing for Alcatel. "We can offer them the gear to do this. Voice over wireless LAN will be just one service that runs over this infrastructure."

But in order for VoIP over Wi-Fi to really take off, it will also have to combine cellular technology, said Joel Conover, an analyst at Current Analysis. Motorola has already started talking about delivering handsets that support both cellular and Wi-Fi access. The company is partnering with VoIP gear maker Avaya and Wi-Fi equipment manufacturer Proxim to develop products that combine cellular, VoIP and wireless technology.

Alcatel and Nortel said the handsets they announced Monday will only support Wi-Fi access. 

2. 
Dailywireless

Enterprise VoIP

Tuesday, March 02 @ 00:19:00 PST

Airespace
has signed separate deals for wireless Voice over IP with Alcatel and Nortel for VoIP. SpectraLink is Alcatel's incumbent's OEM partner (see Alcatel Intros WLAN Products and Nortel Touts VOWLAN). 

Spectralink's s340 and s640 Docking Stations
, which were first announced nearly a year ago, act as charging cradles for SpectraLink's e340 and i640 Wi-Fi handsets and add standard desktop telephone features such as a speakerphone, keypad and display. They will ship in April for $299. SpectraLink is also working on a standalone desktop phone that will feature an integrated 802.11 radio. That phone will be designed for places where it's difficult to run Ethernet or telephone wires.

Airespace already has a WLAN handset partnership deal with SpectraLink, which supplies the phones and quality-of-service software that allows voice traffic to be prioritized on an 802.11 network (see Airespace Talks Up VOIP).

Meanwhile Lucent has teamed with Cisco Systems to develop a carrier-class voice over Internet Protocol (VoIP) and multimedia communications solution for mobile service providers. It uses the Cisco MGX 8000 Series Media Gateways to deliver converged IP-based services -- such as VoIP, high-speed data and multimedia communications -- across third-generation (3G) Universal Mobile Telecommunications System (UMTS) and CDMA2000 and CDMA450 mobile networks. "This will enable operators to take advantage of the tremendous revenue potential, and cost savings made possible by IP technology," ," said John Marinho, vice president of offer management with Lucent's Mobility Solutions Group.

Clay Shirky explains it all; "Where Vonage and a number of the other VoIP startups present themselves to the customer as phone companies, emulating the incumbents they are challenging, you can think of Plan B as the Skype plan. Skype isn't taking on the trappings of a phone company; instead, it offers free two-way voice conversations over the internet."

 

"Wi-Fi and VoIP are powerful technologies on their own, but together, they are far more powerful. It's sort of like adding one plus one and getting three, " says Richard Webb at Infonetics Research.

 

But in order for VoIP over Wi-Fi to really take off, it will also have to combine cellular technology, said Joel Conover, an analyst at Current Analysis. Motorola and Nokia have shown handsets that support both cellular and Wi-Fi access. Avaya and Proxim have teamed to develop Proxim's new AP-4000 with Voice over IP features.

There has been an explosion of SIP Products. VoIP operators like Vonage, SIPphone and 8x8, often use ordinary phones. They plug into an adapter than connects to your broadband connection. Nothing is hotter than Mobilized VoIP. "Free" VoIP services include Skype, Pulver's Free World Dialup and Asterisk, an open-source SIP server.

 

Skype, the "free" VoIP client software that runs on PCs and soon PDAs, is creating quite a buzz on community lans. That's partly because it brings "free" voice to users (when both parties are connected using the internet. The other reason that VoIP has become a hot topic on community LANs is because it "breaks" the captive portal model. A wireless phone has no convenient way to display a splash page and its associated legal disclaimer.

 

That disclaimer, it has been believed, helps to remove legal liability from "free" internet providers. Currently, standalone WiFi VoIP phones may not be able to connect or acknowledge the disclaimer. A method to provide that needs to be developed, say some community lan activists.

BOM DIA!


27/DEZ/2003 - Sábado

 

VoWLAN RIDES AGAIN ...

 

Mais 1 da Série Didática de WLAN. Hoje com VoWLAN.
O que é isto? Vejamos então...
Não existe hoje a VoIP (Voice over Internet Protocol) tomando vulto?  
Veja referências recentes de VoIP:

 

O Skype pode ser um fenômeno em VoIP  do site autoral Alice Ramos

 

RBOC VOIP Coming in 2004 do Magazine Board Watch:
SBC Promises VoIP   from DSL Reports
Bells Join VoIP Push  from DSL Reports

 

 

Então ... VoWLAN é Voice over Wireless LAN
Ué... isto é mais complicado que o VoIP que todo mundo está falando agora? Sim, é bem mais complicado pela natureza Wireless no "negócio". 
Imagina juntar os "pacotes" da sua voz digitalizada quando você caminha de um  Access Point  para outro. Não é uma tarefa simples e está sendo bem endereçada. 
Acreditamos - pelo "andar da carruagem" - que em 2004 teremos excelentes notícias neste terreno.

 

VoWLAN vai ser muito interessante no mercado Corporativo principalmente naquelas empresas aonde vc tem uma grande parte dos empregados 80% do seu tempo de trabalho fora das suas mesas como os segmentos de hotel, de hospital, do varejo e de logística para citar alguns. 

 

1. Veja o que já estão pensando ...

 

Este WISP no Reino Unido jjá quer fornecer o serviço de VoWLAN em 2004.

Smart Convergence  on Saturday, November 22, 2003

UK WISP to offer VoIP
Wi-Fi Planet
By Vikki Lipset
November 21, 2003

Patrons of U.K. hotspots will soon be able to make voice calls over public wireless LANs, thanks to a new service from Internet access provider Broadreach Networks.

The service, called ReadytoTalk, won't officially launch until next summer, but Broadreach will do a test run with 40,000 customers in the interim. The voice over IP (VoIP) service will be an add-on to the company's ReadytoSurf hotspot service, which passed the 500,000 user mark this week.


All ReadytoSurf sites will also be ReadytoTalk-enabled, according to Broadreach CEO Magnus McEwen-King. There are currently 129 ReadytoSurf hotspots in coffee shops, retail stores, hotels and other locations across the United Kingdom.

Like ReadytoSurf, the VoIP service will be offered through ISPs and wireless carriers. Users will need to download software, developed by Broadreach, to their laptop or PDA (McEwen-King said the company plans to support all the major operating systems). Pricing for the service is not yet available.

Broadreach has been contemplating a VoIP service for a while, but has been waiting for the right time to enter the market, said McEwen-King. "VoIP has always been a much talked about proposition, but the quality levels have not been there. However, in the last six months, a number of companies have made significant strides in improving both the costs and quality. We feel there's another few months to go, but now is the time to start doing end-user testing with our ISP and mobile phone operator partners."

See the Press Release
 

2.  Enquanto isto fique com esta boa matéria ... 

 

Voice over wireless LAN: Ready or not?

InfoWorld

By  Nancy Gohring  September 12, 2003   

 

Some hurdles remain, but ubiquitous voice communications may be the killer app for wireless LANs

 

WLANs (Wireless LANs) are still in the experimental phase at most companies. Why? Because wireless security standards remain in flux. But a more obvious obstacle to wholehearted adoption is the lack of a compelling need for wireless in the average office, which already has a perfectly functional, wired LAN in place.

 

Well, here’s a thought: How about replacing or supplementing your current phone system with a VoWLAN (Voice over WLAN) system? Just take an ordinary wireless network and add a VoWLAN server along with laptops, PDAs, or newfangled Wi-Fi phones to run the client. Instead of workers wasting time playing phone tag, they can field calls wherever they roam on campus — or even on the road, if there’s a Wi-Fi cloud nearby.

 

VoWLAN is a natural extension of VolP (Voice over Internet Protocol), a technology that has already taken root in enterprise telecommunications. (Today, more IP-based PBXs are sold than conventional models.) Yet VoWLAN presents its own unique QoS (quality of service) challenges relating to fluctuating wireless throughput and roaming among APs (access points), which is why most of today's local wireless voice systems are bundles of proprietary wireless network hardware and software.

 

Industries with highly mobile workers — such as retail, manufacturing and healthcare — can justify the premium for a proprietary network. (One of the most popular solutions, SpectraLink's Wireless Telephone System, costs between $400 and $700 per seat.) Yet the proliferation of Wi-Fi and its increasing reliability opens the possibility of deploying VoWLANs across commodity WLAN setups at much lower costs.

 

Technical hurdles remain. But on the hardware side, at least, everyone seems to be getting in the game. Cisco recently introduced its first VoWLAN handset and a slew of vendors including NEC, Qualcomm, Motorola and Dell promise hybrid phones next year that use both Wi-Fi and mobile phone networks.

 

A Very Local Exchange

 

“It’s just a matter of time before [VoWLAN] catches on in the mainstream enterprise,” says Ben Guderian, director of marketing for SpectraLink. SpectraLink recently introduced a new, lightweight, less rugged handset designed for mainstream enterprise users. Its lowest priced handset costs $399, which compares to around $350 for many desk phones with standard wiring.

 

Proprietary wireless voice vendors such as SpectraLink and Symbol have been among the first to release VoWLAN solutions for commodity wireless infrastructure. But there’s a new breed of VoWLAN provider as well: the softphone developers. These companies, such as TeleSym, IP blue, and VLI have built software that can be loaded onto PDAs or laptops, enabling users to initiate and receive voice calls over WLANs.

 

Basically, VoWLAN systems work in two different ways. Offerings from SpectraLink, Symbol, and Cisco route calls from the phone to the WLAN AP to a VoIP gateway — one that may already be in use to deliver VoIP over the wired network — which translates calls between the IP network and the PBX. That setup allows all regular PBX functions that are available on workers’ wired desk phones to be available on the VoWLAN phones. Calls that are made to phones outside the enterprise go through the PBX to the PSTN (Public Switched Telephone Network).

 

By contrast, softphone developers such as TeleSym provide systems that route calls outside the enterprise over the Internet. In this scenario, road warriors could use the softphone on their PDA or laptop to place calls from a hotel that offers a WLAN. The call could route entirely over the Internet. “Then the call is completely free,” said Raju Gulabani, TeleSym’s CEO.

 

The downside is QoS. Like any voice call that uses the Internet, users can’t control the quality of the connection.

 

Voice, Interrupted

 

Unfortunately, even over the local network, VoWLAN has its shortcomings. The problem is that the 802.11 standards — including those that cover QoS, security, and roaming — simply weren’t designed to support voice.

 

For example, 802.11 entirely lacks a QoS mechanism. This lack means that no special priority is given to voice, so when traffic spikes on the network, dropouts may occur. The IEEE is working on 802.11e, a QoS standard that should be finalized next year. In the meantime, Symbol and SpectraLink have implemented their own proprietary QoS mechanisms through their hardware.

 

But it’s security, or a lack thereof, that’s the biggest deal breaker for VoWLAN today. Enterprises view today's wireless security measures (such as the Wireless Encryption Protocol) as weak, forcing them to opt for wireless VPNs. But VoWLAN offerings that use phones, as opposed to those that use PDAs or laptops, often can’t employ VPNs because the client software usually can’t be loaded onto the phone. (Several vendors, including NEC and Cisco, plan to produce phones next year with VPN support built in.)

 

But using VPNs for voice has other problems. “A VPN tends to encapsulate voice packets, so it obscures them from the network and it can’t discern high priority voice from low priority data,” says Ron Seide, product line manager for Cisco’s wireless networking business unit. In addition, VPN’s cause latency that degrades the quality of voice, says Richard Watson, an engineer at Symbol and director of telephony product marketing.

 

Instead of using VPNs, users can protect against unwanted intruders by putting voice and data on different subnets or VLANs, allowing clients in the voice subnet to communicate only with the telephone gateway, Watson says. With this separation, the widely used encryption and authentication standards offer good enough security, say some vendors. That’s because the threat of eavesdroppers is remote as the listener would have to be within range of the same AP as the phone user. “The joke here is watch out if you have someone walking behind you with an antenna,” says Watson. “It’s an overblown thing.”

 

An added challenge, though, is that encryption and authentication must happen fast enough so that a call isn’t dropped or degraded when a user moves from the coverage area of one AP to the next. The existing 802.11 standard can’t support that handoff fast enough and neither can the security solutions developed by gateway vendors. Even 802.1x, the upgraded security standard in development, won’t work quickly enough. “When standards bodies developed all this, they were more concerned with security on laptops,” says Watson.

 

The handoff between APs should happen in under 50 milliseconds to cleanly support a voice call, says Doug Klein, CTO of Vernier Networks, a security gateway vendor. Vernier’s gateway does the transfer in a matter of a few hundred milliseconds. “It’s not optimum,” admits Klein.

 

As a result, vendors have developed their own fast authentication processes. These generally work by dispensing a certificate to the client proving that it is authenticated, so that when a user moves into range of another AP, the client offers that certificate as proof of authentication.

 

Cisco employs a similar scheme, where one AP is designated as a master AP within a subnet. Rather than require each AP to acquire an encryption key from a backend server as the user roams, the master AP gets a master key and from that, each AP in the subnet spawns a session key. But even Cisco’s solution takes 150 milliseconds.

 

Maybe Next Year

 

The available VoWLAN security solutions aren’t robust enough for many enterprises. “I don’t think it’s likely that we’ll be deploying VoIP on Wi-Fi networks anytime soon,” says Joshua Wright, senior network and security architect for Johnson and Wales University, which already has an extensive WLAN for data users. Current offerings don’t enable the kind of reliability he wants in a voice network.

 

The efficiency of the security and QoS also affects the load that APs can handle. Most AP vendors say each AP can support 10 simultaneous calls, but when pressed, will usually admit to half that number in live deployments. Chris Kozup, META Group's program director of technology research service, says his clients who have tested VoWLAN report on average four or possibly five calls without any data use per AP. “It becomes a problem because there are finite resources here in terms of channel and frequency,” Kozup indicates. “It’s not as easy as lighting up another AP.”

 

New standards, including the faster 802.11g and the QoS specification, 802.11e, should increase the number of users an AP can support. Combined, those upgrades could allow 15 to 25 simultaneous calls, says Cisco's Seide.

 

Ultimately, although the hurdles of deploying a robust VoWLAN are many, they are also surmountable. The key to robust and reliable VoWLAN networks lies in the ability to support security and all capabilities fast enough to hand off between APs seamlessly. As more customers demand support for voice, vendors say they’ll deliver it. “We’ll get around to doing the work that needs to be done,” said Vernier’s Klein.  

 

3. Veja Notícias do IEEE sobre QoS (IEEE 802.11e)

 

Status of Project IEEE 802.11e

MAC Enhancements for Quality of Service
 

The purpose of Task Group E is to: Enhance the current 802.11 MAC to expand support for applications with Quality of Service requirements, and in the capabilities and efficiency of the protocol. 

 

4. Um Trabalho Nosso sobre o Assunto

 

Voz sobre wireless LAN (VoWLAN) do site autoral Alice Ramos 

 

5. Uma Grande Matéria sobre o Assunto

 

VoIP unwired
By Phil Hochmuth
Network World
July 28, 2003
 
Voice and wireless Ethernet might seem an odd mix, but for mobile workers or hard-to-wire areas, it can be the perfect combo.
 
Converged voice/data network projects can be tough, especially if you can't use any wires. That's what Mike Burns, a systems integrator, discovered when a client asked him to provide voice and data services to a gold-mining operation in the middle of a Laotian jungle. Burns faced a sticky situation - literally. 
 
"The ground was mostly mud, so we couldn't bury any cables, and there were no poles where we could hang wire," says Burns, who is president of Nationwide Computer Systems, an ISP and integration firm in Fort Lauderdale, Fla. The solution would obviously be a wireless one: Burns used 802.11b gear to connect 50 IP phones, PCs, a router and satellite dish for the mining camp. The camp, which stretches over a two-mile area, consists of 20 structures for operations, living quarters and offices. 
 
Eu gosto desta figura aqui ...
[Figura grande - Aguarde a carga se a conexão estiver lenta]



Wi-Fi VoIP: Behind the curtain at one medical center
University of Southern California University Hospital uses QoS technology on
a Wi-Fi gateway and at the LAN switch to ensure wireless IP voice calls 
get priority as they crosss the LAN 

 

 


  
1 BOM SÁBADO COM "VOZ DIGITAL" !!!
 


17/NOV/2003 - Segunda-feira

 VoIP & VoWLAN: Um Folhetim sobre estes 02 "moços" .... 
 

Por onde começamos? ... Afinal "são tantas emoções" !
 
1. Definições 
 

VoIP = Voice over Internet Protocol
 
VoWLAN = Voice over Wireless LAN (WLAN)  
 
2. Veja algumas referências de VoWLAN ...  

[a] Wi-Fi Planet
 
VoWLAN: Not Ready for Prime Time

Pocket PCs Dial Up Wireless VoIP

Voice over 802.11: An Emerging Market

Dartmouth Intros Wireless VoIP
 
[b] Outras 

VoIP Unwired
 
Will Wi-Fi lower nurses' blood pressure?
 
Dutch Hospital in Spectralinks
 
[c] Uma do Protocolo SIP 

Carriers Say VOIP & SIP Are Hot  
 
3. Um Texto Nosso 

Voz sobre wireless LAN (VoWLAN) 
Site autoral Alice Ramos
http://www.aliceramos.com/conver/0019.asp
 
Existem problemas? Sim... ainda existem. O site
Unstrung mostra uma dura realidade. Todos esses vendors que estão trabalhando com a tecnologia de VoIP, no padrão 802.11, antes que a especificação de WLAN para suportar voz tenha sido finalizada pelo IEEE, podem ter problemas - isto é, antes que o padrão IEEE 802.11e seja finalizado.  
 
4. Serviços Mundiais de VoIP 

Vonage
 
Net2Phone
 
8x8 Inc
 
Free World Dialup
 
Conexão PC-para-PC: Skype
 
 
5. Super-Informações de VoIP 

Voice over IP and IP Telephony: References
 
Voice Over IP do Dailywireless  
 
7. Wi-Fi Phones 

Palm GPhone
 
Pocket GPhone 2.0
 
Motorola Wi-Fi Phone do Dailywireless
 
Palm VoIP do Dailywireless
 
Free Voice over Wi-Fi do Dailywireless
 
Wi-Fi Phones do Dailywireless
 
Can Wi-Fi Kill Cellular? do Dailywireless
 
Free World Dialup do Dailywireless
 
Handsets Key to VoIP do Dailywireless
 
 
8. PBX IP um importante componente para GERAR RECEITA !!! 

Spectralink's New PBX to VoIP Gateway
  
Start-up unveils four-channel VoIP product
Last modified: October 29, 2003, 10:21 AM PST
By Dawn Kawamoto
Staff Writer, CNET News.com

i2 Telecom announced a four-channel Voice-over-Internet-Protocol product for small businesses on Tuesday, marking the latest product debut for the communications start-up.

The company unveiled its E-VoIP 4000, which aims to lower companies' telephone bills by allowing users to make long-distance and international calls over the Internet. Voice over Internet Protocol (VoIP), a concept that has been hyped for years, is finally gaining momentum as broadband adoption accelerates.

The E-VoIP 4000 has four channels, or the equivalent of four telephone lines, that are used to switch the last leg of callers' calls from the Internet to traditional phone providers.

If a company has multiple offsite locations, an E-VoIP can be placed in each office and the entire call can be placed via the Internet, said Rick Scherle, the company's senior vice president of marketing.  
 
UFA !!! Boa Semana para Todos ... 


From Google:
 


VoWLAN Network Planning and Operations

Published: October 2004
134 Pages
Author: Bruce Hall


Related VoIP Training (Click Here)

Also see: VoWLAN Fundamentals
Broadband Wireless Network Planning Toolbox
and VoWLAN Products and Services


Setembro 08, 2004

Voice over WLAN: Analysis Is The Key To Success

With VoIP comes the notion to run voice on 802.11 wireless LANs (WLANs). But to succeed, Voice over WLAN (VoWLAN) deployments need very careful planning and continuous monitoring.

By Scott Haugdahl, CTO, WildPackets

IP voice applications have already presented new quality of service challenges on wired networks. Data applications could easily tolerate fluctuations in available bandwidth, but the same typical anomalies will drive voice users crazy.

And while most wired LANs have enough bandwidth overhead available so that network engineers can prioritize voice traffic using standard quality of service mechanisms, wireless LANs are bandwidth constrained; that makes the job of offering quality voice services much harder.


However, network engineers can use wireless protocol analyzers to create a better VoIP experience for their users. IMHO, these protocol analyzers should include the following:

VoIP, WLAN and LAN-specific protocol decodes and filters for common problems in these environments;
VoIP call recording and playback, with Mean Opinion Score (MOS) evaluation;
Analytical analysis of packet delay variation and jitter;
Ability to track open calls in real-time and to post closed calls;
Quick drill down to the problem at hand without resorting to complex filtering;
Expert system technology that parses the flood of packet capture information and suggests sources of problems or recommends specific actions.

With these tools in hand, there are two main steps to the VoWLAN rollout process: pre-deployment planning and post-deployment troubleshooting and optimization.

Pre-Deployment

Wireless LAN performance varies widely with the number of clients on the network, their distance from the nearest access point (AP), and the specific environmental characteristics of the coverage area (furniture, building materials, elevator shafts, etc.).

In a voice deployment, the WLAN must support higher and more deterministic bandwidth rates. Ideally, every VoWLAN user should be communicating at the maximum throughput (11Mbps on 802.11b, for example), so the AP placement and configuration in a voice network will be different than it is for a data-only WLAN. Coverage may also be needed in areas normally not occupied by desktop and laptop users.

Protocol analyzers help in planning a VoWLAN deployment because you can use them to:

test the networks throughput;
determine the level of channel interference between access points;
monitor the quality of voice calls at various locations on the network;
and confirm that QoS prioritization polices are working properly.

Here are some pre-deployment questions to resolve and how a protocol analyzer can help answer them:
How many simultaneous voice calls will the WLAN handle? Using a protocol analyzer, you can measure in real-time the quality of voice and quantity of data of a test group of users associated with a given access point.

Investing in a small quantity of wireless VoIP phones (or having a vendor provide evaluation units) will go a long way toward revealing problems early on. You may discover that to maintain good quality, only seven to eight users of full-duplex G.711 VoWLAN phones can supported in one <@BCI>cell<@BCR> area simultaneously.

Where should the access points be placed for optimum voice performance? One of the emerging "best practices" for VoWLAN is to have a higher density of access points and to disable data rates below 11 Mbps, since lower data rates propagate and can reach other access points on the same channel even if they aren't neighbors.

Protocol analyzers can be used to confirm that you have adequate coverage at 11 Mbps in areas where users may roam (including hallways and stairwells) and to ensure that there is no overlapping channel interference from other access points.

Are some segments more robust than others? Why? With a laptop or tablet WLAN protocol analyzer, you can roam your space with ease and measure the signal strength and interference from neighboring channels, from access points on the same channel but some distance away, or simply from other sources of 2.4 GHz RF, such as microwave ovens, cordless phones, Bluetooth, and so on.

Such interference will usually cause a much higher rate of wireless retransmissions and frames with CRC errors.

Post-Deployment

After deployment, the WLAN environment will change constantly depending on which users are doing which activities when, and where they are doing them.

Always keep in mind the mobile aspects of a WLAN -- the network will need ongoing tuning and management to maintain optimum performance. WLAN switch vendors offer ways to tune the network by adjusting AP power levels, prioritizing traffic at the WLAN switch, or implementing QoS at the client and AP.

However, there are a lot of other variables that affect voice performance, such as dropped packets, handoff delays, simultaneous two-way conversations, and security attacks.

Here's a look at how protocol analyzers can assist with identifying and managing these problems.

Dropped Packets

VoIP is susceptible to the same momentary delays and errors that are common to any wireless LAN application, and network performance can vary widely as the user roams or as other users join or leave the network. Such problems quickly degrade voice quality.

With the help of an expert system, the analyzer can determine if any delayed VoIP packets are likely to be dropped by the receiver. This is a somewhat complex operation that basically boils down to analyzing the variability in packet delay and determining which packets may be outside the receiver's jitter buffer for a given codec and arrival rate. This is important, since it is no longer a simple matter of checking for the absence of a packet in the analyzer's capture buffer.

Another technique for mixed LAN/WLAN systems is to put an analyzer in the traffic path on the wired side of the internal network to perform additional call and quality analysis. Many VoIP devices send out periodic reports containing jitter information experienced by the receiver. This way, one can see the real jitter as experienced by the end-nodes at both ends of the conversation without having to place an analyzer at each of those end points.

Hand-Off Delays

Users roaming from one AP's coverage area to another AP's coverage area must be handed off from one AP to the next. When the handoff time is too long, the user can experience clicks, delays in picking up the conversation again, or even a disconnected call.

A protocol analyzer can be used to look at the re-association and recovery of problem calls in real time in order to directly correlate the user experience with actual packet activity and anomalies. The analyzer's VoIP expert system can be an enormous time saver in detected these anomalies.

Simultaneous Conversations

Simultaneous two-way conversations can double the bandwidth requirement for IP phones and thereby slow traffic. Two people won't necessarily be talking at the same time, but any background noise at the listener's location is also transmitted while the other party is talking. Some codec protocols and phones can use noise suppression (which can squelch transmitted packets from a user that is merely listening), but most do not.

Therefore, there is almost always a continuous stream of packets transmitted in both directions during a call.

An analyzer can be used to measure the bandwidth consumed and jitter characteristics of a call (since in essence we are performing full duplex operation on a medium that only allows transmission in one direction at a time), as well as the impact as we add more users.

Security Attacks

As an IP service, VoIP is equally susceptible to security attacks, which can immediately and dramatically affect voice service quality. A VoIP analyzer built on a proven core of protocol analysis and expert system technology can help identify these attacks by triggering events on suspect data such as a worm or unexpected spike in response time or throughput.

Even though VoIP traffic on wireless networks should be encrypted, it's still possible to analyze the traffic by looking for problems such as congestion, CRC errors, wireless retransmissions, frequent drops in wireless data rates, and frame arrival rates (to and from the physical address of the VoWLAN phone).

For VoIP phones that use a static WEP key, network engineers can obtain the key from an administrator and plug it into their analyzer to fully decode all seven layers of protocols.

Conclusion

The number of variables to manage in a VoWLAN application can be daunting, but they're by no means insurmountable. Properly armed with the right protocol analysis tools along with an understanding of VoIP protocols and WLAN anomalies, network engineers can go far to ensure a relatively trouble-free deployment of voice over wireless LAN.
--------------------------------------------------------------------------------

Scott Haugdahl is the chief technology officer at WildPackets where he developed the expert system for the AiroPeek NX 802.11 wireless analyzer. He has more then 20 years of experience in the networking industry and is author of the book "Network Analysis and Troubleshooting." WildPackets, as you either knew or gleaned from his vendor-neutral article, makes network management tools.
 



VoWLAN Heats Up

By Vikki Lipset

03/03/2004

In what could be a big boost for the growing voice over wireless LAN (VoWLAN) market, Nortel Networks (Quote, Chart) and Alcatel (Quote, Chart) both announced offerings this week that add voice capabilities to their WLAN product lines.

The companies will resell Wi-Fi handsets, access points (AP) and switches from SpectraLink (Quote, Chart) and Airespace. Both Nortel and Alcatel say their versions bring something extra to the table.

"It's their hardware, but our special sauce," said Diane Schmidt, director of marketing for Nortel's WLAN portfolio, of the company's new Adaptive WLAN deployment solution, which is comprised of a security switch and access ports that the company says are optimized for VoWLAN.

She pointed to the ability to monitor and control the radio frequency domain as an example. This is key for customers who are looking at real-time applications such as wireless IP telephony and need nonstop coverage over their WLAN, she said.

"If there's a gap in coverage due to some interference or an AP drops out for some reason, because we have control over what happens across the air, we're able to transfer those connections to a device that can handle them, so users won't experience any downtime."

Nortel is also offering additional security features. "We're bringing the capabilities of our security switch -- things like rogue access point detection, support for VPNs -- into this solution as well," Schmidt noted.

"We've brought this airtight security into a realm that's notoriously porous," added Nortel spokesman Pat Cooper.

The Adaptive WLAN package will be available next month. It includes the 2230 (a/b/g) and 2231 (b/g) Access Ports ($599 and $499 respectively) and the 2270 Security Switch (starting at $10,999). The new Nortel VoWLAN products, which include the 2210 and 2211 handsets ($695 and $890 respectively), the WLAN IP Telephony Manager 2245 ($2500) and the WLAN Application Gateway 2246 (starting at $1600), are expected to be available in May.

Meanwhile, Alcatel is offering APs, switches and appliances under the OmniAccess name. OmniAccess 4000 wireless switches start $8,250, OmniAccess 4100 wireless appliances start at $13,685 and OmniAccess 1200 Access Points start at $400.

The company will introduce its version of SpectraLink's wireless handsets, branded as Mobile IP Touch 300 and 600, in September. The phones will work with Alcatel's OmniPCX family of IP-PBX systems.
 



Talking about Securing VoWLAN

By Eric Griffith

05

Embracing voice over IP (VoIP) as the hot new thing in LANs in general -- and wireless LANs in particular -- is not exactly news these days. VoIP is the buzzword of the moment, so it's no surprise when a company like Aruba Networks says it's going to have a "full solution for VoIP in the enterprise."

The difference with Aruba is, they've got partners like SpectraLink (Quote, Chart), Avaya (which rebrands SpectraLink phones), voice-badge maker Vocera, and soft-phone designer Telesym -- names that encompass almost all the major players in Voice over WLAN (VoWLAN). SpectraLink alone held 60% of the global market for VoWLAN products in the year 2003 according to Synergy Research Group. The nearest rival, Symbol, provides about 7% of the world's VoWLAN products.

Aruba also says it will differentiate its VoWLAN support from other switch vendors by concentrating on security.

"There's a huge security hole for voice," says Keerti Melkote, Aruba's co-founder and vice president of product marketing. "Handsets and the technology today are a generation behind the state of the art -- the handsets mostly use MAC address (define) authentication and WEP (define). Static WEP is weak and can be broken and using a MAC address [means] that once that address is admitted, it can go wherever. Spoof that and it can send non-voice packets into the network" to cause a disruption.

Aruba will also be doing some new radio frequency (RF) management to reserve bandwidth and perform load balancing for calls at the access point (AP), all for voice traffic.

The Aruba switch will be able to make a "virtual AP in the air for voice, and operate it with specific power management profiles that are custom built for voice," says Melkote. This profile will take into consideration that phones aren't connected to the network at all times, unlike most WLAN data devices. By contrast, Meru Networks, a switch competitor of Aruba's, recently announced a proprietary solution involving the licensing of firmware to Wi-Fi handset vendors to do the same thing. Meru's switch system has been previously tested as interoperable with Symbol and Vocera products.

Melkote says the Aruba 5000 Switch could handle 5000 calls simultaneously, with a varying number of calls per AP depending on the type of VoWLAN clients due to the codecs and compression schemes used by each of its partners.

Aruba is breaking its voice support into three separate phases. The first is simply to have interoperability with its announced partners; for example the switch will support SpectraLink's Voice Priority Protocol. Phase 2 will include using standards such as Quality of Service from the proposed 802.11e standard and fast-hand off from the 802.11r standard announced at the last IEEE (define) meeting of the 802.11 Working Group. Aruba also plans to support the Session Initiation Protocol (SIP). Phase 3 is well down the road: they plan to offer seamless handoff from cellular to Wi-Fi networks.

Aruba is demonstrating its VoWLAN solution with SpectraLink in London this week at the Wireless LAN show.


VoWLAN: The Wireless Voice Future is Here ... Almost
June 14, 2004
By Beth Cohen

Chris Taylor, Telecommunications Manager, Metro Toronto Convention Centre had a serious problem. His mission critical Nortel "Companion" 900Mz phone system was no longer supported and he needed a replacement system double quick. With 2 million square feet of open exhibition space spread over two buildings, he needed a communications system that provided roaming and instant communications, an open flexible data network, and a minimum of wires. A year ago, he started looking at wireless networking combined with VoIP (Voice over IP) or VoWLAN (Voice over IP over Wireless) as part of the total networking solution. As Taylor put it, "My three goals were to provide wireless data networking for exhibitors, create a corporate profit center by selling services to the exhibitors, and meet employee data/telecommunications needs. The combination of VoIP and wireless networking fit the bill exactly."

With 55 million lines and 15% of the voice market, VoIP is an established and rapidly maturing technology. It has been proven to be less expensive to install and maintain; the core equipment is comparable in cost to traditional voice, and it offers many more integration options. Wireless technology is also rapidly maturing, so the next obvious step is to deploy a converged technology. Until a few months ago, the converged technology suffered from proprietary equipment, weak security, and a lack of scalable network management tools: It was not quite ready for prime time. All that has changed in the past year. The VoWLAN landscape is rapidly changing with evolving standards, new equipment, and finally some good management tools. Let us look at some of the issues that were plaguing VoWLAN and how the fledgling industry is successfully addressing them.

Approaching Technological Liftoff
According to Bob Myers, CTO and co-founder of Chantry Networks, a company that develops wireless network management systems, VoWLAN is growing rapidly in certain vertical industries like health care, hospitality, retail and manufacturing. Industries where the flexibility, combined voice and data requirements are so compelling that they are willing to forgo the current lack of handset hardware, network management tools and poorly addressed security, standards, and QoS (Quality of Service) issues.

Part of the problem is that wireless is a contention media -- the users share the available bandwidth -- so wireless will always have overhead issues and more complex management requirements. Another overlooked issue is how to determine good coverage. In an open field, coverage is easy to determine, but most IT people don't have the specialized knowledge required to plan an installation for a complex environment like a hospital, with all its attendant equipment and building structures.

Myers notes, "Health care's transition to VoWLAN came about because they had widely deployed 802.11 so they were already comfortable with the technology. The hospitality and retail sectors both have a widely dispersed work force that needs to be in constant communication. Both industries were previously using the 900Mz Walkie-Talkie systems, so conversion to VoWLAN was a natural next step. Beyond those specific industries, uptake has been slow because of the perceived security issues and lake of management tools." Recently, there has been a major change in perception as companies discover the benefits of increased flexibility, the improved security standards, and the always popular, substantially lower operational costs.

Wireless Network Management
A critical component to the success of VoWLAN is sophisticated wireless network management tools. As Myers puts it, "Unlike all previous computer technology, wireless networking, wireless came back into the enterprise from the SOHO and home markets. With a three node network, you don't need management tools." When rolling out enterprise wide wireless, especially VoIP, the need for prioritized data streams, transparent access point handoffs, and seamless security are essential. Chantry offers a management package that is designed to specifically address these issues. Other companies, like Avaya and Cisco who are heavily invested in developing this market, are also working to develop new tools.

Continued on Page 2: What Else is There to Think About?

QoS (Quality of Service) and Reliability
Wireless service quality is technologically a step 10 years backwards. For data packet delivery, companies are willing to trade mobility and reduced costs for reliability, but voice packets are more sensitive to perceptible service degradation. As Myers puts it, "You really need to have a max of 150ms to make sure users are not bothered by QoS issues when you are using a VoIP system. Cellular has gotten people used to a lower QoS compared to traditional voice, but not entirely."

To make matters worse, the WME (Wireless Multimedia Extensions) 802.11e wireless QoS standard will not be ratified until the end of 2004 or early 2005. Most wireless equipment has not yet incorporated any QoS because they are waiting for the emerging standards. Because this is such a critical piece for a successful VoWLAN deployment, some companies are implementing a subset of 802.11e. Another gotcha is that while 802.11b officially delivers 11MB with QoS, the actual useable bandwidth is really closer to 6MB. Remember that 6MB is shared by anyone on the access point. VoIP has a tendency to have small packets with a large overhead. With 10 to 15 VoIP users you are quickly down to unacceptable modem-level data rates. The reality is that with most wireless equipment, planners should expect 6-7 voice calls maximum per channel. With Chandra's priority queuing and predictive handoffs, they can support up to 15 voice streams in addition to a small amount of data traffic. By limiting the number of voice calls on a single access point, the software can maintain the required QoS.

Security
Wireless security is finally improving with the newer WPA and WPA2 standards, but these emerging standards have not been fully adopted into the VoWLAN equipment yet. 802.11r is a brand new IEEE taskforce created specifically to address VoWLAN security issues. Expect to see handsets incorporating the improved security standards in 6 to 8 months, and new standards in this area in a year or so. According to Myers, part of the problem is the need to re-authenticate every time users move between access points. Session switching can cause unacceptably high delays (up to 500ms) or dropped calls. Obviously the re-authentication process is in direct conflict with the QoS requirements of maintaining the call data stream. Chantry has incorporated a virtual network service that preloads the VoIP session security at the backend as the user roams the network so the call session is transparently switched to the new access point minimizing signal delay.

Staffing and Operational Issues
Unless you were a tiny company that had an IT generalist, the data and telecom support staff have, until recently, not needed to learn each other's methodologies and equipment. The current trend is to merge the support functions and staff for more efficient operations, but there is still a time lag in training and operational efficiencies, as the staff learn the new equipment and procedures.

Hardware What Hardware?
Currently there are two main companies in the VoWLAN handset market, Vocera and SpectraLink. SpectraLink owns 75% of the total handset market and the majority of the health care market with systems in 1600 hospitals nationwide. Vocera is startup breaking into retail and health care. Because they were first to market, neither of these are standards based systems. Both Cisco and Symbol (the people who invented barcode scanners) have handsets as well. According to Chris Taylor, Symbol has recently dropped the VoWLAN line to focus on their core market. All the products suffer from short battery life and reliability problems. As PoE (Power over Ethernet), standards and cellphone technology is incorporated, expect to see a plethora of better handsets within the next few months.

Are We There Yet?
How is Chris Taylor doing with his VoWLAN system? He reports that they have had the beta system in place since January. They are planning a full rollout to completely replace the old "Companion" system by September. "The staff loves it. The voice quality is good and roaming is completely transparent. Just make sure all the vendors' equipment is compatible and integrated. That was the key to success for our installation."

Should you be seriously considering Voice over IP over wireless LAN solutions today? Well yes and no. Unless you are in the health care, manufacturing, or retail industries where the ROI is especially compelling, the technology is still not quite ready to be heard yet. With the maturing of both the VoIP and wireless technologies, on the surface merging the two emerging technologies might seem to be a terrific idea. However, security issues, poor quality equipment, and bandwidth prioritization considerations point to a technology that is still too immature for anybody to deploy unless they are ready to put up with the bleeding edge phase of the innovation curve. In the next 8 to 12 month there will be numerous new products that will be addressing these and other issues as many innovative technology companies work on solving the problems. Once the issues have been properly addressed and the standards settle down, VoWLAN with its potential to merge data, voice and mobility into one neat package, promises to be something that could transform how companies do business.

--------------------------------------------------------------------------------
Beth Cohen is president of Luth Computer Specialists, Inc., a consulting practice specializing in IT infrastructure for smaller companies. She has been in the trenches supporting company IT infrastructure for over 20 years in different industries including manufacturing, architecture, construction, engineering, software, telecommunications, and research. She is available for consulting to help your company identify the right IT infrastructure to meet your business objectives.

 

Complemente sua pesquisa: Google (com opção de páginas em português)

"Direitos"
Todo o conteúdo sobre Tecnologia deste Blog foi coletado na web via sites de busca ou enviado por colaboradores voluntários, com o único propósito de informar e compartilhar conhecimento, sem finalidade comercial. Tecnologia, neste caso, é sinônimo de organizações, empresas, produtos e serviços. Há sempre preocupação em citar as fontes. No entanto, se alguma pessoa , física ou jurídica, sentir-se prejudicada em seus direitos, basta um comunicado e a matéria será reformulada ou retirada. 

All the contents about technology of this Section were collected in the web via search sites or were sent by voluntary collaborators, with the only purpose of informing and sharing knowledge. Technology, in this case, is a synonim for organizations, enterprises, products and services. There will be always the preoccupation in mentioning the sources.. However, if any person or enterprise will happen to feel damaged in their rights, they may just send a note and the material will be reformulated.