This specification addresses the linkage between session control and bearer level resource control mechanisms. The linkage is defined through two interfaces. One interface (Tx) connects the Policy and Charging Rules Function PCRF) to an Application Function (e.g., P-CSCF) that is responsible for application level service decisions. The other interface(Ty) connects the PCRF to the AGW (e.g., PDSN) that is responsible for bearer resources policy enforcement. The PCRF acts as a Policy Decision Point from the perspective of policy control.

The Tx and Ty interfaces shall allow:

1. Interactions for the purpose of application authorization of bearer level QoS resources based on the resources negotiated at the application layer.

2. Coordination between the application and the bearer level for per flow accounting

3. Notification of loss of bearer from the bearer control entity to the application

4. Application control of the flow of packets on the bearer including the restriction of flow end-points (flow filtering).

5. General policy considerations for the allocation of resources on the bearer in the local domain.

The specification should also consider subscription based authorization of flows.