scope:

This standard provides an overview of the capabilities of the ANSI Broadband ISDN Network Node Interface (B-ISDN NNI) for the Broadband ISDN Signaling Capability Set 2, Step 1 (B-ISDN NNI CS 2.1). This standard should thus be seen as an increment to ANSI T1.648, Section 1 which provides an overview of the B-ISUP for Signaling Capability Set 1.

The B-ISDN NNI CS 2.1 builds upon the B-ISUP defined for Signaling Capability Set 1. The B-ISUP for CS 1 provides call control for point-to-point single connection calls using ISDN bearer classes BCOB-A and BCOB-X. B-ISDN NNI CS 2.1 adds further call control capabilities, additional bearer types, additional connection topologies, and some dynamic re-arrangement of these.