E.3 Binding Mechanisms

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

E.3.1 EPC-routed traffic

For EPC- routed traffic, binding mechanisms apply as defined insub clause 5.1 by PCRF, PCEF and BBERF. In addition, if both a Gx and associated S9a session exist for the same IP-CAN session, the PCRF shall generate QoS Rules for all the authorized PCC rules.

E.3.2 NSWO traffic

The binding mechanism includes two steps for the NSWO traffic:

1. Session binding.

2. PCC rule authorization.

For NSWO traffic, session binding of AF session to an IP-CAN session is performed by the PCRF for the purpose of policy control in the Fixed Broadband access network.

When the PCRF accepts an AA-Request from the AF over the Rx interface with service information, the PCRF shall perform session binding and associate the described service IP flows within the AF session information (and therefore the applicable PCC rules) to one and only one existing IP-CAN session. This association is done comparing the user IP address received via the Rx interface in either the Framed-IP-Address AVP or the Framed-Ipv6-Prefix AVP with the Ipv4 address or Ipv6 address/Ipv6 prefix received via the S9a or S9 interface. The user identity if present in the Subscription-Id AVP and the PDN information if available in the Called-Station-Id AVP may also assist on this association.

The PCRF determines that the UE has an IP-CAN session if the IP address (Ipv4 or Ipv6) received over the Rx interface matches the Ipv4 address or Ipv6 address/Ipv6 prefix received via one or more of the following interfaces: S9a interface and S9 interface, and if the user identity is used to assist the association, the user identity received over the Rx interface matches the user identity received via one or more of the following interfaces: S9a interface and S9 interface.

NOTE 1: In case the user identity in the IP-CAN and the application level identity for the user are of different kinds, the PCRF needs to obtain the mapping between the identities. Such mapping is not subject to specification within this TS.

NOTE 2: An Ipv6 address provided over Rx matches an Ipv6 prefix provided over S9a or S9 if the Ipv6 address belongs to the Ipv6 (sub-)network prefix.

As a result from the session binding function, the PCRF identifies what IP-CAN session the current AF session is related with. If the PCRF is not capable of executing the Session Binding, the PCRF shall issue an AA-Answer command to the AF with a negative response.

NOTE: For roaming cases, the H-PCRF performs session binding of the AF session to an IP-CAN session.

The PCRF derives and authorises PCC rules as described in clause 5.