Question 13/II - Design alternatives for telecommunication networks
(Continuation of Questions 27/II and 41/II,
1985-1988 study period, amended)

Considering

(a) that sophisticated routing methods may be applied to networks
designed under simpler assumptions;

(b) that more cost efficient utilization of networks can be attained,
especially for intercontinental networks, by the use of dynamic
routings, in which routing patterns are changed (for instance, time or
state dependent) according to the traffic profile;

(c) that certain network design alternatives might yield a more robust
network and thereby reduce the impact of a failure or unexpected
traffic overload on the GOS as perceived by the customer;

(d) that the network needs to be planned to incorporate restoration
and diversity in order to increase the level of network survivability;

(e) that Recommendation E.522 incorporates a multi-hour engineering
procedure and considers the impact of transit charges on
dimensionings;

(f) that Recommendation E.175 outlines a possible international
network planning process and this process involves steps requiring the
review of network design alternatives;

(g) that selective trunk reservation may be applied to bi-directional
circuit groups;

(h) that in ISDN, due to a higher level of concentration, services may
require new GOS and dependability constraints, and that these may
differ from different services;

(i) that dependability covers the aspects of availability performance,
reliability performance, maintainability performance and maintenance
support performance;

(j) that network design should simultaneously take both trafficability
and dependability into account;

(k) that Recommendation E.862 provides procedures for the planning of
the dependability of telecommunication networks;

(l) that Recommendation E.880 provides guidelines for the collection
and evaluation of data on dependability;

(m) that the E.500 Series of Recommendations contains guidelines for
the collection of trafficability data,

1. What traffic dimensioning methods and network design alternatives
are available for single and multiservice networks, especially with
priority and multi-bandwidth capabilities?

2. What computations are required and what pertinent parameters
should be measured for various network design alternatives, in
particular for reference networks and service protection methods?

3. What is the most appropriate basis for comparison of different
network alternatives?

4. What methods should be recommended for the estimation of the
economic impact of traffic disturbances in telecommunication
networks?

5. How should traffic disturbance be evaluated for a network and
balanced against network investments?

6. What guidelines should be provided to assist the planning and
economic evaluation of telecommunication networks with sufficient
dependability?

Note - Liaison must be maintained with Study Groups IV and XV taking
account of the partition of work described by Study Group IV (see COM
IV-R 14, 1985-1988 study period)