02/06/2006

In this page: VOIP/IP Telephony concepts and Regulation.


VoIP / IP Telephony

 

Products and VOIP Services Guide

Consult and Sign your company in ( portuguese)

 

Consult Teleco's list of internet VOIP provider

 

VoIP

 

VoIP is a set of technologies that uses the Internet or private IP networks for Voice communication, substituting or complementing the conventional telephony systems.

 

Communication
Characteristics

Computer to Computer

  • Peer-to-peer;
  • Uses free services such as Skype, MSN Messenger, Yahoo Messenger, among others;
  • The computers are responsible for call signaling and control.

Computer to telephone

  • PSTN Gateway needed;
  • Peer-to-peer up to the gateway;
  • uses pre or post paid services such as the SkypeOut, Net2Phone, V59, among others;
  • The gateway is responsible for call signaling and control.

 

 

Regulations

 

Anatel regulates telecommunications services and do not regultates the technologies used to implement them. VoIP technologies are used only for implementing the telephony services, but they are not the service itself. A specific regulation for VoIP in Brazil does not exist yet.

 

Tutorials

(portuguese)

Rgulation section:

www.teleco.com.br/tutorias.asp

 

FAQ - Regulations Aspects for IP Telephony

 

 

IP Telephony

 

IP Telephony is a VoIP based service which presents quality and functionalities that are, at least, equivalent to the conventional telephony services. The subscriber needs an IP telephone or an IP adapter for a conventional telephone and an IP broad band service to connect to the IP telephony network. In addition, the service can be accessed from a computer running a soft-phone software.

 

Service

Characteristics

Consumer

  • Provided by Operators with IP Telephony Networks that are interconnected to the conventional telephony networks (public and cellular services) ;
  • The Operator provides the IP telephone or IP adapter and the broad band connection;
  • The subscriber receives a phone number from the operators assigned numbering range;
  • Originates and receives calls either for/from IP telephones and conventional telephones (public and cellular services);
  • In addition, the subscriber can be connected to the Operator network through any IP broad band connection, either in the subscriber address or any other addresses, using the same phone number and even keeping the contracted service rates;
  • Call control and signaling (as well as the aditional services and gateways) are managed by equipments especially designed for this purpose(Soft-switches);
  • Examples of IP Telephony Operators: Vonage, AT&T - CallVantage e GVT.

Enterprise

  • Uses IP PBX's and corporative data networks;
  • The user uses a computer or an IP telephone or an IP adapter and a data connection from the corporative network;
  • The user receives a number from the corporative extensions numbering range;
  • Originates and receives calls either for/from IP telephones, computers and conventional telephones (public and cellular services);
  • The user can be connected to the corporative network eihter in the regular office or any another address of the company keeping the assigned extension number and configured services;
  • Call control and signaling (as well as the aditional services and gateways) are managed by equipments especially designed for this purpose (Call Manager).

 

 

Protocols for VoIP / IP Telephony

 

Signaling IP Protocols (Call control)

  • H.323 - Packet Based Multimedia Communications Systems (ITU-T). Used by IP telephones, computers, IP adapters, signaling controllers (soft-switches and call managers) and gateways for call control (establishment and hang-up). It is an older and complex protocol and it has been used with less frequency in IP telephony systems.
  • SIP - Session Initiation Protocol (IETF). It has the same purpose of H.323, however it is a modern and less complex protocol, and it has been used more frequently in VoIP systems.

Gateway Control Protocols (Signaling)

  • MGCP - Media Gateway Control Protocol (IETF). Used by gateways controllers and gateways for call control (establishment and hang--up).
  • MEGACO - Gateway Measured Protocol Control (IETF/ITU-T). It has the same purpose of MCGP, however it was developed to be an alternative protocol, which can be used by gateways distributed controllers, multicast controllers (Conference) and interactive audible reply units.

Media Protocols (Voice Transport)

  • RTP - Real-Time Transport Protocol (IETF). Responsible for Real -time Voice transport between computers and gateways. It is currently the preferred standard for this purpose.

     

    RTCP - Real-Time Transport Control Protocol (IETF). Responsible for controlling the Voice transport performed by RTP in VoIP systems.

 

Additional Information

 

Teleco Tutorials

(portuguese)

Teleponia IP
Transporte de Sinalização em Redes IP
Estratégia de VoIP das Operadoras de TV a Cabo
PABX IP
Soluções Corporativas usando VoIP
Solução Corporativa VoIP: Caso Prático
Internet
VoIP Center
IPTelephony.org

 

 

 

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