Question 12/XVIII - Interworking between networks using different
digital hierarchies - Layer 1 functionality

Considering

(a) that I.500-Series Recommendations specify the general principles on
interworking between networks including ISDN and other networks;

(b) that Recommendations I.511 and G.802 specify, in particular, the
Layer 1 functions necessary for interworking between networks including
those incorporating different standards and hierarchies;

(c) that Layer 1 broadband aspects of ISDN described in Recommendation
I.121 including the possible impacts of ATM need further consideration
for interworking;

(d) the existence of synchronous digital hierarchy and its relevant
frame formats and functions specified in Recommendations G.707, G.708
and G.709 along with the likely long-term existence of equipment based
on the existing different asynchronous hierarchies and standards;

the following should be studied:

1. What new or revised Recommendations are requested for interworking
between networks using different hierarchies?