P-Early-Media SIP Header Support

Version S-CZ7.2.0 provides support for the SIP P-Early-Media that can be used in SIP INVITES, PRACKS, and UPDATES to request and authorize the use of early media. It offers an alternative to policy-based early media support.

The P-Early-Media SIP header is defined in RFC 5009, Private Header (P-Header) Extension to the Session Initiation Protocol (SIP) for Authorization of Early Media. RFC 5009 defines the use of the P-Early-Media header within SIP messages in certain SIP networks to authorize the cut-through of backward (server-to-client) and/or forward (client-to-server) early media when permitted by the early media policies of the networks involved. The P-Early-Media header field is intended for use in a SIP network, such as a 3GPP IMS that has the following characteristics: its early media policy prohibits the exchange of early media between end users; it is interconnected with other SIP networks that have unknown, untrusted, or different policies regarding early media; and it has the capability to gate (enable/disable) the flow of early media to/from user equipment.