Back-to-back user agent

Back-to-back user agent

The Back-to-Back User Agent (B2BUA) acts as a user agent to both ends of a Session Initiation Protocol (SIP) call. The B2BUA is responsible for handling all SIP signalling between both ends of the call, from call establishment to termination. Each call is tracked from beginning to end, allowing the operators of the B2BUA to offer value-added features to the call.

To SIP clients, the B2BUA acts as a User Agent server on one side and as a User Agent client on the other (back-to-back) side. The basic implementation of a B2BUA is defined in RFC 3261. The B2BUA may provide the following functionalities:

* call management (billing, automatic call disconnection, call transfer, etc.)
* network interworking (perhaps with protocol adaptation)
* hiding of network internals (private addresses, network topology, etc.)
* codec translation between two call legs

Because it maintains call state for all SIP calls it handles, failure of a B2BUA affects all these calls. Often, B2BUAs also terminate and bridge the media streams to have full control over the whole session.

A Signaling gateway, part of a Session Border Controller, or Asterisk PBX are good examples of a B2BUA.

ee also

*Session Border Controller
*User agent

External links

* [ Open Source Sippy SIP B2BUA]

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Back to Back — may refer to * Back to Back , a 1983 album by Status Quo * Back to Back (album) , an album by a combination of The Shadows and The Ventures * , an album by Duke Ellington and Johnny Hodges *Back to back houses, a form of terraced house, common in …   Wikipedia

  • Agent-based model — An agent based model (ABM) (also sometimes related to the term multi agent system or multi agent simulation) is a class of computational models for simulating the actions and interactions of autonomous agents (both individual or collective… …   Wikipedia

  • Software agent — In computer science, a software agent is a piece of software that acts for a user or other program in a relationship of agency, which derives from the Latin agere (to do): an agreement to act on one s behalf. Such action on behalf of implies the… …   Wikipedia

  • List of User Friendly characters — User Friendly characters are the characters that feature on the webcomic User Friendly. Contents 1 Main characters 1.1 A.J. 1.2 The Chief 1.3 Dust Puppy …   Wikipedia

  • Conversational agent — Conversational agents (CAs) are communication technologies that utilize natural language and computational linguistic techniques to engage users in human like, Web based “dialogs.” They can support a broad range of applications in business… …   Wikipedia

  • Ssh-agent — is a program that used together with OpenSSH or similar ssh programs provides a secure way of storing the passphrase of the private key. Public key cryptography plays the central role in the idea of logging in to a server from a local machine via …   Wikipedia

  • IP Multimedia Subsystem — Das IP Multimedia Subsystem (IMS) ist eine Sammlung von Spezifikationen des 3rd Generation Partnership Project (3GPP). Ziel von IMS ist ein standardisierter Zugriff auf Dienste aus unterschiedlichen Netzwerken. IMS verwendet ein All IP Netzwerk,… …   Deutsch Wikipedia

  • SIP — (англ. Session Initiation Protocol  протокол установления сеанса)  протокол передачи данных, который описывает способ установления и завершения пользовательского интернет сеанса, включающего обмен мультимедийным содержимым (видео и …   Википедия

  • Video share — is an IP Multimedia System (IMS) enabled service for mobile networks that allows users engaged in a circuit switch voice call to add a unidirectional video streaming session over the packet network during the voice call. Any of the parties on the …   Wikipedia

  • List of SIP software — The following lists of SIP software documents software applications which use SIP as a voice over IP (VoIP) protocol. SIP servers Free and open source * Asterisk (PBX) * FreeSWITCH * Mysipswitch * SailFin * SIP Express Router (SER) * sipX… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”