Alternate Simultaneous Capabilities and Offers in the Session Description Protocol (SDP)
NexTone Communications
This document defines Session Description Protocol (SDP) attributes and semantics to express alternate capabilities and offers. The attribute "cgroup” is defined to express alternate simultaneous sets of capabilities. The “ALTS” semantics are defined to express specific alternate simultaneous offers. Existing methods like the MIME multipart/alternative subtype and the use of multiple session descriptions in SDP are also discussed.