 TCP connections P-CSCF load balancing for midcall Uas SIP resource priority header (GETS) Session agent status based on SIP response SIP session agent ping response code settings Session router-session agent constraints SIP Retry-After Support Session Agent Group recursion control SIP method transaction stats SIP INFO to RFC-2833 DTMF interworking SIP response map per sip-interface SIP TCP keepalive support SIP TCP implicit connection reuse and dialog/transaction changes SIP SDP public IP encoding for upstream policy control SIP: Session Agent-configurable interval to reopen TCP connection 166 SIP Trunking SIP Methods SIP uses Methods/Requests and corresponding Responses to establish a call session. Here are the requests and responses defined for SIP: SIP Requests: There are six basic request/method types: INVITE = Establishes a session ACK = Confirms an INVITE request BYE = Ends a session CANCEL = Cancels establishing of a session REGISTER = Communicates user location (hostname, IP) OPTIONS = Communicates information about the capabilities of the calling and re- ceiving SIP phones SIP responses: SIP Requests are answered with SIP responses, of which there are six classes: 1xx = Informational responses, such as 180, which means ringing 2xx = Success responses 3xx = Redirection responses 4xx = Request failures 5xx = Server errors 6xx = Global failures You need to include the following requirements as part of SIP Methods in your RFP: RFC-3261: ACK, BYE, CANCEL, INVITE, OPTIONS, REGISTER PRACK (RFC-3262): Reliability of provisional responses in SIP SUBSCRIBE (RFC-3265): SIP Specific Event Notification NOTIFY (RFC-3265): SIP Specific Event Notification PUBLISH (RFC-3903): SIP Extension for Event State Publication INFO (RFC-2976): SIP INFO method UPDATE (RFC-3311): SIP UPDATE method MESSAGE (RFC-3428) REFER (RFC-3515) SIP Refer Method Chapter 9: Questions to Ask of a Service Provider Offering and an SBC Vendor IETF and General SIP Support The Internet Engineering Task Force (IETF) works with a lot of RFCs (Request Fo