Summary

This Recommendation specifies a mapping function that allows B‑ISDN data communications applications utilizing protocol stacks which include SSCOP (Recommendation Q.2110) also to be deployed in an HDLC-based environment. The required mapping function is called "convergence function for SSCOP above the frame relay core service".

This Recommendation makes use of the fact that the subset of services provided by AAL type 5 (Recommendation I.363.5) that SSCOP uses can also be provided by the services of the core service for the frame mode bearer services (Annex A/Q.922).

This Recommendation also provides, in Annex A, suggested parameter values for use in support of SS No. 7 applications. Such an arrangement would allow one approach to a migration from N‑ISDN to B‑ISDN.

This Recommendation is applicable to equipment to be attached to a frame relay network when protocol stacks developed for a B‑ISDN environment are deployed in a narrow-band environment.