A Taxonomy of Session Initiation Protocol Back-to-Back User Agents
RFC 7092, “A Taxonomy of Session Initiation Protocol Back-to-Back User Agents”, is an Informational document published in December 2013 by H. Kaplan, V. Pascual. The canonical text is published by the RFC Editor.
Abstract
In many SIP deployments, SIP entities exist in the SIP signaling path between the originating and final terminating endpoints, which go beyond the definition of a SIP proxy, performing functions not defined in Standards Track RFCs. The only term for such devices provided in RFC 3261 is for a Back-to-Back User Agent (B2BUA), which is defined as the logical concatenation of a SIP User Agent Server (UAS) and User Agent Client (UAC).
There are numerous types of SIP B2BUAs performing different roles in different ways; for example, IP Private Branch Exchanges (IPBXs), Session Border Controllers (SBCs), and Application Servers (ASs). This document identifies several common B2BUA roles in order to provide taxonomy other documents can use and reference.
What “Informational” means
Published for the general information of the community. It does not define an IETF standard and carries no standards-track status.
The canonical text of RFC 7092 is hosted at rfc-editor.org. Available in TXT,HTML.
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