http://www.rfc-editor.org/rfc/rfc4896.txt
RFC 4896: Signaling Compression (SigComp) Corrections and Clarifications, A. Surtees, M. West, A.B. Roach2007-06-01T23:00:00-00:00This document describes common misinterpretations and some ambiguities in the Signaling Compression Protocol (SigComp), and offers guidance to developers to resolve any resultant problems. SigComp defines a scheme for compressing messages generated by application protocols such as the Session Initiation Protocol (SIP). This document updates the following RFCs: RFC 3320, RFC 3321, and RFC 3485. [STANDARDS-TRACK]