E.8 Session Linking Function

29.2133GPPPolicy and charging control signalling flows and Quality of Service (QoS) parameter mappingRelease 17TS

PCRF and BPCF needs to support session linking function. The PCRF shall be able to perform the linking between multiple Gx and Gateway Control Session to the same S9a session.

When receiving an IP-CAN Session Establishment request or an IP-CAN Session modification request with an UE local IP address or H(e)NB local IP address, the PCRF shall perform the session linking between the S9a session and the corresponding Gx session according to the UE Local IP address/ H(e)NB local IP address.

When receiving a Gateway Control Session Establishment Request or a Gateway Control and QoS Rule Request with UE local IP Address or a H(e)NB local IP Address change, the PCRF shall perform the session linking between the S9a session and the Gateway Control Session according to the UE Local IP address/ H(e)NB local IP address.

If there is not an established S9a session which could be linked to the Gx or Gateway Control Session, the PCRF shall initiate the S9a Session Establishment trigger procedure.

For 3GPP HNB Procedures with CS support, the PCRF shall be able to perform the linking between S15 sessions and the S9a session.

NOTE 1: There is a single S15 session per HNB for CS calls for all Ues connected to the HNB in order to improve performance. In addition, for CS calls there are no UE specific policies and therefore a single PCRF can handle CS calls for all Ues.

Annex F (normative):
Access specific aspects, Fixed Broadband Access network convergence