Methods for enhancing SDP preconditions signalling for IP multimedia sessions

A machine readable medium, comprising:

• a session description message including:
• a media line;
• and
• at least two separate direction tags for said media line.

A method of processing communications session establishment signals, the method comprising;

• operating a first network element to process a first session description message including at least two direction tags for a media line, the two direction tags including a send tag and a receive tag;
• and
• the first session description message further including a plurality of additional tags associated with each of said send and receive tags, said processing including:
• merging the send and receive tags into a combined send/receive tag when the additional tags associated with each of the send tag and the receive tag are the same.

A machine readable medium, comprising:

• a session description message including:
• a media line;
• and
• a direction tag;
• one of a success and a failure associated with said direction tag indicate success or failure at meeting a session precondition;
• and
• one of an option and mandatory indicator also being associated with said direction tag.