Question 5/XVIII - General aspects of Quality of Service and network in
digital networks, including ISDNs

Note - To be studied in close consultation with Study Group II and other
related Study Groups.

1. What general Quality of Service parameters for telecommunication
services should be recommended and how should they be structured?

2. What digital network performance parameters (including availability)
should be recommended for ISDN connection types and how should they be
structured?

3. How do the Quality of Service parameters of an ISDN telecommunication
service relate to the network performance parameters of ISDN connection
types(s) which support that service?

4. How does the performance of the equipment in the customer
installation interact with the network performance to influence the
Quality of Service of telecommunication services? Account should be
taken of standards set by other bodies?

5. What are the performance considerations resulting from the
integration of mobile networks into the ISDN?

6. Do particular services (e.g., audiovisual, broadcast, multipoint, and
multimedia services) require particular consideration, and if so, in
what way?

7. Where are the boundaries in an international ISDN connection at which
performance can be measured and allocated among the network entities?

Note - These apportionment boundaries will be used in answering
Questions 6, 8, and 9.

8. What are the performance significant reference events that can be
observed at those boundaries and can be used in defining a comprehensive
set of ISDN performance parameters?

Note - These reference events will be used in answering Questions 6, 8,
and 9.

9. How do the specific ISDN performance parameters defined under
Questions 6, 7, 8, and 9 fit this general model (I.350)?

10. What are the appropriate parameters for Quality of Service and
network performance in a B-ISDN, taking account of the following:

a) that B-ISDN will build on the very high bandwidth and low error
properties of many available transmission systems;

b) that Asynchronous Transfer Mode and other possible B-ISDN transfer
modes introduce the possibility of impairment mechanisms (e.g., cell
loss due to congestion) which, if not controlled, may mask the inherent
high performance capabilities of the transmission facilities;

c) that these transfer modes may impact the manner in which network
impairments are perceived by the end user?

11. What performance related guidance can be given to the other
concerned groups concerning the development of B-ISDN architecture and
protocols?

12. How should the performances of digital sections be specified?