Question 20/XV - Characteristics of digital cross-connect equipment

Considering

(1) that there is a need at digital network nodes for the flexible
cross-connection, at different hierarchical levels, of channels, groups
of channels and digital links;

(2) that studies of the new synchronous hierarchy include cross- connect
arrangements;

(3) that progress in studies of digital network structures may result in
the interconnection of network terminations without the use of digital
exchanges being recommended for certain applications;

(4) that Recommendation G.707 gives the hierarchical bit rates for a new
synchronous hierarchy;

(5) that Recommendation G.708 gives a Network Node Interface for a new
synchronous digital hierarchy;

(6) that there is a need to interconnect signals between systems
operating at 1544 kbit/s and 2048 kbit/s.

(7) that there is a need to transport and distribute broadband signals
in digital networks,

1. What should be recommended for the characteristics of synchronous
cross-connect equipment for digital signals, and groups of signals?

2. What should be recommended for the characteristics of plesiochronous
cross-connect equipment for digital signals?

Points for study

1.The signals, groups of signals and digital link bit rates that should
be switched.

2.Characteristics of transmission electrical interfaces.

3.The multiplexed bit rates required at the transmission interfaces.

4. Size and modularity.

5. Synchronization interfaces.

6. Overhead processing.

7. Pointer characteristics.

8.Environmental conditions, if some other studies appear necessary.

9. Maintenance aspects.

10.Application of Operations, Administration and Maintenance interfaces
as given in Recommendation G.771 - any unique features required.

11.The types of data channel required between cross-connect equipments
and a Telecommunications Management Network (TMN).

12.The type of information, signalling and control signals that may need
to be exchanged between cross-connect equipment and a TMN.

Notes

1. Operations, Administration and Maintenance interfaces on transmission
equipment are studied under Question 9/XV.

2. Account should be taken of the studies of the new synchronous
hierarchy being undertaken by Study Group XVIII.