As stated in [ITU-T Y.1271], enhanced priority treatment is an essential requirement for the assured
capabilities needed for emergency telecommunications. One critical component is admission
control and associated priorities as described in [ITU-T Y.2171]. Another critical component is
service restoration particularly during emergency conditions with potentially reduced network
bandwidth/resources. Under such conditions, emergency telecommunications interrupted by
network failures require preferential restoration treatment. In the NGN, assured restoration can be
enabled by:
1) development of service restoration priority levels based on the criticality of services;
2) development of the necessary extensions in signalling protocols that can indicate the
restoration priority levels during call/session set-up;
3) development of restoration mechanisms that can recognize the signalled priority levels and
undertake the necessary restoration/re-routing action.
The scope of this Recommendation is limited to the development of priority levels for service
restoration in the NGN. This guidance can be helpful in the development of the subsequent
signalling extensions and restoration mechanisms.
Administrations may require operators and service providers to take into account national
regulatory and national policy requirements in implementing this Recommendation.