SIGTRAN and SIP-T

The IETF's Signalling Transport working group has developed SIGTRAN to address the transport of packet-based PSTN signalling over IP Networks, taking into account functional and performance requirements of the PSTN signalling. For interworking with PSTN, IP networks will need to transport signalling such as Q.931 or SS7 ISUP messages between IP nodes such as a Signalling Gateway and Media Gateway Controller or Media Gateway.

Applications of SIGTRAN include Internet dial-up remote access and IP telephony interworking with PSTN.

See the SIGTRAN charter

SIP-T

SIP-T (SIP for telephones, previously SIP-BCP-T) is a mechanism that uses

SIP to facilitate the interconnection of the PSTN with IP. This is intended to allow traditional IN-type services to be seamlessly handled in the Internet environment. It is essential that SS7 information be available at the points of PSTN interconnection to ensure transparency of features not otherwise supported in SIP. SS7 information should be available in its entirety and without any loss to the SIP network across the PSTN-IP interface. SIP-T defines SIP functions that map to ISUP interconnection requirements.

The SIP-T RFC 3372 is available on the IETF site