AAL type 2 signalling protocol Capability set 2 Annex D: SDL definition of the AAL type 2 signalling protocol CS-2 SERIES Q: SWITCHING AND SIGNALLING Broadband ISDN Common aspects of B-ISDN application protocols for access signalling and network signallin
This new annex contains a comprehensive definition of the AAL type 2 signalling procedures in
SDL. The data structures required for the SDL definition as well as the data structure for the
messages in the main part of the Recommendation are specified in ASN.1.
Although, the SDL definitions contain more detail than the prose definition in clause 8, the
definitions in clause 8 take precedence. Nevertheless, this new annex clearly indicates which part of
the procedures specified in clause 8 are left to individual implementations and which part of the
procedures must be implemented precisely for conformance with this Recommendation.
In addition, this new annex demonstrates that semi-formal definitions for signalling protocols are
possible.