ITU-T Q.3307.1 PDF

The protocol specified in this Recommendation is used to support inter-domain PD-PE communication when the service control entity (SCE) is not capable of interacting with the PD-PE in each domain crossed by the media flow.

The Ri interface is used to control session-based policy. Using the protocol specified in this Recommendation, the original PD-PE can:

– provide information to the peer PD-PE to identify media flows and their required QoS resource characteristics (e.g., QoS class, bandwidth, priority);

– provide service priority information to the peer PD-PE to facilitate appropriate priority handling;

– request resource usage information through the peer PD-PE for charging;

– indicate if the media is recommended to be enabled (i.e., gate opened) when resources are reserved;

– indicate if the media is recommended not to be enabled as soon as the resources are reserved, i.e., the original PD-PE can optionally request that the media gate be opened later;

– if a network address and port translation (NAPT) function is required, request address mapping information so it can do any modifications that may be required for application signalling (e.g., SDP); and

– if a path-coupled resource reservation mechanism is used, indicate to the peer PD-PE whether it wishes to be notified when reservations are obtained and released.

When an authorization token mechanism is used, the peer PD-PE may supply the original PD-PE with one or more authorization tokens which the SCE is required to include in the application signalling messages to the customer premises equipment (CPE).

This Recommendation only discusses per session reservation. The functional requirements and the stage 2 specification for this interface are defined in [ITU-T Y.2111]. As indicated in [ITU-T Y.2111], this Recommendation only supports nomadism; other use cases are for further study.