ABSTRACT
This section describes Request for Comments (RFCs) 5432, 3556, 3605, 3890, and 5898 that deal with quality-of-service (QOS) support in Session Description Protocol (SDP). The QOS support in multimedia applications is essential especially for real-time and near-real-time audio and video applications. Although the QOS requirements for nonreal-time applications (e.g., text and data applications) may not be as stringent as that of real-time and near-real-time applications, the support for QOS mechanisms like Resource Reservation Protocol specified in RFC 2205 and Next Steps in Signaling protocol defined in RFC 5974 in SDP are essential for negotiating the specific QOS parameters of multimedia applications among the conferencing parties. RFC 5432 defines a mechanism that allows endpoints to negotiate the QOS mechanism to be used for a particular media stream. It is important to note that QOS parameters negotiated at the multimedia application layer are not sufficient unless the same is supported in the network layer. The network layer QOS in support of the application layer QOS is orthogonal; it is not defined in RFC 5432 and needs to be worked out separately.
