A Private Integrated Service Network (PISN) is a network comprising either one PINX or more than

one PINX interconnected by Inter-PINX connections. This Technical Report is concerned with inter-

PINX connections (IPC) that are provided by Intervening Networks (IVN), and the way in which these

are handled by PINXs to provide a platform for inter-PINX communication. Different types of IVNs

can be used to provide IPCs, in accordance with the scenarios indicated in ISO/IEC 11579-1. These

are Overlay Scenarios in that they enable the services of the PISN to operate transparently across

an IVN.

Connected PINXs need to co-ordinate their use of IVNs, and appropriate standardisation is needed

to allow networks to be created employing PINXs and IVNs from multiple vendors. The following

points need to be considered:

_ In general but depending on the type of IVN, procedures and signalling protocols between the

PINXs are needed for the establishment, maintenance and release of IPCs. Appropriate

standardisation of these procedures and signalling protocols is necessary.

_ At the Q reference point (a conceptual point within a PINX) channels and PISN call control

signalling (QSIG) are defined independently of the type of IVN. However, at the C reference

point (where the PINX is connected to the IVN), the representation of the channels and of

signalling is dependent on the type of IVN, and on how the PINXs use the IPCs. Appropriate

standardisation of these aspects at the C reference point is necessary.

_ In general the relationship between a channel at the Q reference point and its representation at

the C reference point is not static, and procedures and signalling between the PINXs are needed

for the co-ordination of these relationships. Appropriate standardisation of these procedures and

signalling is necessary.

_ Appropriate mechanisms need to be standardised for conveying inter-PINX signalling through

the IVN. These will depend on the characteristics of the IPC used.

The aim of this Technical Report is to identify:

1. In addition to PISN call control signalling (QSIG), what needs to be standardised, in order to be

able to inter-connect PINXs;

2. General techniques, procedures, protocols etc., that apply to of all (or at least very many) types

of IVNs.