The Session Description Protocol (SDP) provides mechanisms to describe attributes of multimedia sessions and of individual media streams (e.g., Real-time Transport Protocol (RTP) sessions) within a multimedia session. Typically media associated with individual media descriptions ("m=" lines) represent seperate RTP Sessions and are thus carried over individual underlying transport layer flows. For scenarios where SDP is used to negotiate the usage of single 5-tuple for sending and receiving media associated with multiple media descriptions, it is required to understand the semantic implications of the SDP attributes associated with the RTP Media Streams multiplexed over a single underlying transport layer flow. The purpose of this specification is to provide a framework for analyzing the multiplexing characteristics of SDP attributes. This specification also categorizes the existing SDP attributes based on the framework described herein.