Question 17/VII - Arrangements for CSPDNs interworking and associated
internetwork signalling (new Question derived from Question 21/VII
studied in 1985-88)

Considering

(a) that the provision of data services may require several networks to
interwork;

(b) that framework of X-Series Recommendations related to interworking
is given in Recommendation X.300;

(c) that common channel signalling for data applications is specified in
Recommendation X.61 and that decentralized signalling for anisochronous
and synchronous data networks is specified in Recommendations X.70 and
X.71 respectively;

(d) that requirements of interworking of signalling in accordance with
Recommendations X.61, X.70 and X.71 are specified in Recommendation
X.80;

(e) that studies are continuing on the implementation of user facilities
and network utilities and on the interworking between different
signalling systems;

(f) that it is desirable to coordinate the specification of additions to
Recommendations X.61, X.70 and X.71 resulting from any new common
requirements for inter-exchange signalling for the circuit switched
service,

1. What additions, if any, are required to Recommendations X.70 and
X.71?

2. What additions, if any, are required to Recommendation X.80?

3. What guidelines need to be defined for specification of additions, if
any, to Recommendation X.61 resulting from common requirements?

Note - For this study, collaboration with Study Groups IX and XI should
be made, as necessary.