Discovering Proxies Supporting SIP Outbound
This document describes modifications to DNS procedures used to resolve a SIP Uniform Resource Identifier (URI) into the IP address, port, and transport protocol of the next hop to contact. These modifications enable the SIP User Agent (UA) to discover those proxies, within the domain of the SIP URI, that support SIP extensions described in draft-ietf-sip-outbound document. The introduced mechanisms update behavior defined in RFC 3263.