A Session Initiation Protocol (SIP) Feature Tag for Back-to-Back User Agents (B2BUAs)

Document Type Expired Internet-Draft (individual)
Authors Ram R  , Tirumaleswar Reddy.K  , Gonzalo Salgueiro 
Last updated 2016-01-07 (latest revision 2015-07-06)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


The User Agent capabilities specification allows Session Initiation Protocol (SIP) User Agents to convey their capabilities and characteristics to other User Agents and to the registrar for its domain. This information is conveyed as parameters of the Contact header field. Amongst those capabilities are the type of User Agent that is available at a SIP Uniform Resource Identifier (URI). This document extends the User Agent capabilities specification to allow indication of Back-to-Back User Agent (B2BUA) types.


Ram R (rmohanr@cisco.com)
Tirumaleswar Reddy.K (tireddy@cisco.com)
Gonzalo Salgueiro (gsalguei@cisco.com)

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)