IETF RFC 7434 PDF

The motivation and use cases for interworking and transporting Userto‐ User Information (UUI) from the ITU‐T Digital Subscriber Signalling System No. 1 (DSS1) User‐user information element within SIP are described in RFC 6567. As networks move to SIP, it is important that applications requiring this data can continue to function in SIP networks as well as have the ability to interwork with this ISDN service for end‐to‐end transparency. This document defines a usage (a new package called the ISDN UUI package) of the User‐to‐User header field to enable interworking with this ISDN service.

This document covers interworking with both public ISDN and private ISDN capabilities, so the potential interworking with QSIG will also be addressed.

The package is identified by the new value "isdn‐uui" of the "purpose" header field parameter.