Cisco Systems The Session Description Protocol (SDP) was intended for describing multimedia sessions for the purposes of session announcement, session invitation, and other forms of multimedia session initiation. SDP was not intended to provide capability indication or capability negotiation, however over the years, SDP has seen widespread adoption and as a result it has been gradually extended to provide limited support for these. SDP and its current extensions however do not have the ability to negotiate one or more alternative transport protocols (e.g. RTP profiles) which makes it particularly difficult to deploy new RTP profiles such as secure RTP and RTP with RTCP-based feedback. The purpose of this document is to identify a set of requirements for SDP Capability Negotiation and evaluate existing work in this area. The document does not provide any solutions to SDP Capability Negotiation