Question 12/II - Traffic, operational and network planning objectives
of common channel signalling networks (Note 1)
(Revised Q.26/II from 1985-1988)

Considering

(a) that CCITT Recommendations in the Q.700 Series specifying the
structure and design criteria for CCITT Signalling System No. 7, are in
an advanced stage;

(b) that such Recommendations on structures and design criteria need
to be complemented by Recommendations on the operational and
traffic aspects;

(c) that the common channel signalling networks are different from the
speech (and non-speech) networks, e.g., structure, traffic performance
and network availability;

(d) that the common channel signalling networks will carry many
different types of information through the user and application parts of
Signalling System No. 7, including in particular user-to-user signalling
information and signals related to supplementary services (e.g., credit
card validation);

(e) that the end-to-end performance of the various user networks will
depend on how well signalling networks are configured and
dimensioned;

(f) that proposed and existing signalling networks are packet switched
type networks and are an essential part of end-to-end ISDN capability;

(g) that CCITT Recommendations in the E.700 Series specifying the
traffic aspects of ISDN are available;

(h) that these signalling networks require evaluation of signalling
routing techniques, interworking with network management techniques
and new traffic measurements,

1. What new traffic models and performance measures are needed to
dimension common channel signalling networks?

2. What information about the interworking of ISDN networks and the
common channel signalling network is needed to perform CCS network
dimensioning?

Note 1 - This Question is closely related to the Question of Study
Group XI and Questions 9, 16 and 10 of Study Group II. In the course of
studies under this Question new requirements may emerge in the areas
of signalling routing, measurement parameters, and network
management which will be identified to the relevant Question.