A.5 3GPP Accesses (GERAN/UTRAN/E-UTRAN) – PMIP-based EPC

23.2033GPPPolicy and charging control architectureRelease 17TS

A.5.0 General

For 3GPP Access (PMIP-based), architecture details are described in TS 23.402 [18].

When PMIP-based S5/S8 has been deployed, the IP‑CAN-specific parameter exchange occurs by means of IP‑CAN Session Modification messages including the necessary information.

A.5.1 High Level Requirements

A.5.1.0 General

The same requirements as in clause A.4.1 apply for 3GPP Access (PMIP-based).

A.5.1.1 QoS control

For 3GPP Access (PMIP based) the same requirements as defined in clause A.4.1.2 apply.

A.5.2 Architectural Model and Reference Points

A.5.2.1 Reference architecture

In the 3GPP Access (PMIP-based) architecture, see TS 23.402 [18],

– the Policy and Charging Enforcement Function is allocated to the PDN GW;

– the Bearer Binding and Event Reporting Function (BBERF) is allocated to the Serving GW.

The Gxx applies and corresponds to the Gxc, as defined in TS 23.402 [18]. One Gateway Control Session corresponds to one IP‑CAN session.

A.5.3 Functional Description

A.5.3.1 Overall Description

A.5.3.1.1 Binding mechanism

The same considerations as in clause A.4.3.1.3 apply with the following modifications:

– For the 3GPP Access (PMIP-based) the Bearer binding is performed by the BBERF.

A.5.3.1.2 Credit management

For 3GPP Access (PMIP-based EPC) the same credit re-authorisation triggers as defined in table A.4.3-1 apply.

A.5.3.1.3 Event triggers

For 3GPP Access (PMIP-based EPC) the same event triggers as defined in table A.4.3-2 apply. However, they apply at the BBERF (and not at the PCEF) upon the request from the PCRF.

NOTE: The request from the PCRF can be triggered by configured policy, a request received from the PCEF or request received from the TDF. For a PCEF or TDF based request, this may be a result of credit re-authorization trigger received by the PCEF or by the TDF from the OCS.

A.5.3.2 Functional Entities

A.5.3.2.1 Policy Control and Charging Rules Function (PCRF)

For 3GPP Access (PMIP based) the same requirements as defined in clause A.4.3.2.1 apply with the following modification:

– Default EPS Bearer QoS and Subscribed APN-AMBR are provided by the BBERF.

For 3GPP Access (PMIP based), the PCRF receives information about supported bearer establishment modes from the PCEF and provides the bearer establishment mode to be used to the PCEF, i.e. in the same way as for 3GPP Access (GTP based).

A.5.3.2.2 Policy and Charging Enforcement Function (PCEF)

For 3GPP Access (PMIP based) the same requirements as defined in clause A.4.3.2.2 apply with the following modification:

– For the 3GPP Access (PMIP-based) the enforcement of the Authorized Default EPS Bearer QoS is not performed by the PCEF.

A.5.3.2.3 Bearer Binding and Event Reporting Function (BBERF)

In the 3GPP Access (PMIP-based) the BBERF enforces QoS Policies as indicated by the PCRF in accordance to what is stated in clause 6.2.7.3 with the following additions:

– Authorized Default EPS Bearer QoS Enforcement. The BBERF receives the authorized QoS for the default bearer over Gxx interface. The BBERF enforces it which may lead to the upgrade or downgrade of the default EPS Bearer QoS. The BBERF shall re-evaluate the bearer binding (as defined in clause 6.1.1.4) taking into account the default bearer QoS change and any QoS Rule operation requested by the PCRF.

A.5.3.3 Void

A.5.3.4 Void

A.5.3.5 IP-CAN bearer and IP-CAN session related policy information

For 3GPP Access (PMIP based) the same requirements as defined in clause A.4.3.4 apply.

A.5.3.6 TDF session related policy information

For 3GPP Access (PMIP based) the same requirements as defined in clause A.4.3.5 apply.

A.5.4 PCC Procedures and Flows

A.5.4.1 Introduction

For the 3GPP Access (PMIP-based), the IP‑CAN session is established by the Proxy Binding Update message to the PDN-GW. The IP‑CAN session is terminated when the PMIP session is terminated.

From the network scenarios listed in clause 7.1, the Case 2b applies.

A.5.4.2 Gateway Control Session Establishment

For the Gateway Control Session Establishment Procedure (see clause 7.7.1), the Serving GW includes the following additional information in the Gateway Control Session Establishment message (in addition to the parameters described in clause 7.7.1): User Location Information, user GSG information, (if received from the MME), Serving-GW address, Serving Network, RAT Type, Default EPS Bearer QoS and if available the APN-AMBR are provided to the PCRF.

The PCRF includes, in the Acknowledge Gateway Control Session Establishment (in addition to the parameters described in clause 7.7.1): QoS Rules with QCI and ARP matching the Default EPS Bearer QoS. If the bearer establishment mode is UE/NW, the PCRF may also include QoS Rules requiring a QCI and ARP different from the Default EPS Bearer QoS and for which NW mode applies.

In support of PDP Context Activation procedures over S4, the BBERF must indicate various session parameters, e.g. the RAT type, to the PCRF.

The PCRF may provide the following parameters in the Acknowledgement of the Gateway Control Session Establishment to the Serving GW (in addition to the parameters described in clause 7.7.1): Authorized APN-AMBR, Authorized Default EPS Bearer QoS.

If the PS to CS handover indicator is set for an IP-CAN bearer that is deleted, the BBERF reports termination of transmission resources for associated QoS Rules due to PS to CS handover.

A.5.4.3 Gateway Control and QoS Rules Request

In the case of Gateway Control and QoS Rules Request (described in clause 7.7.3) the BBERF includes the addition/modification/removal of any the 3GPP specific information listed in clause A.5.4.2.

When a change of RAT without S‑GW relocation occurs, the BBERF signals the RAT type change as a parameter in an event report sent from the BBERF to the PCRF. An event report is the then sent, indicating the RAT type change, from the PCRF to the PCEF.

When Secondary PDP Context Activation occurs, the S4 SGSN performs a Request Bearer Resource Allocation procedure with the Serving GW. The Serving GW supplies the parameters required by the PCEF to properly handle the allocation of resources. These parameters are sent from the BBERF (Serving GW) to the PCRF for further processing when a PMIP-based S5/S8 is deployed.

The PCRF may provide the following parameters in the Acknowledgement of the Gateway Control and QoS Rules Request to the Serving GW (in addition to the parameters described in clause 7.7.3): Authorized APN‑AMBR, Authorized Default EPS Bearer QoS.

For the purpose of event reporting to the PCEF the BBERF may generate Event Reports to the PCRF if this has been requested by the PCRF.

A.5.4.4 Gateway Control and QoS Rules Provisioning

In the case of Gateway Control and QoS Rules Provisioning (described in clause 7.7.4) the PCRF may provide the following parameters (in addition to the parameters described in clause 7.7.4) to the Serving GW: Authorized APN‑AMBR, Authorized Default EPS Bearer QoS.

Whenever the PCRF modifies the Authorized Default EPS Bearer QoS, the PCRF shall simultaneously modify the QCI and ARP of all QoS Rules that, according to the operator policy, shall have the same QoS as the default bearer.

A modification of the Authorized Default EPS Bearer QoS requires that at least one QoS Rule with a matching QoS can be bound to the default bearer as defined in clause 6.1.1.4.

NOTE: The network configuration can ensure that at least one QoS Rule is bound to the default bearer by applying operator policies in the PCRF ensuring that a QoS Rule with matching QoS will be active.

For the purpose of event reporting to the PCEF the PCRF may request Event Reports from the BBERF. In response to such request the BBERF shall provide the present value(s) of the event parameters.

A.5.4.5 IP‑CAN Session Establishment

The PCRF may provide the following parameters in the Acknowledgement of the IP‑CAN Session Establishment to the PDN GW (in addition to the parameters in clause 7.2): Authorized APN‑AMBR, User Location Information, user GSG information (if received from the BBERF).

A.5.4.6 IP‑CAN Session Modification

A.5.4.6.1 IP‑CAN Session Modification; GW (PCEF) initiated

The PCRF may provide the following parameters in the Acknowledgement of the IP‑CAN Session Modification to the PDN GW (in addition to the parameters in clause 7.4.1): Authorized APN‑AMBR.

A.5.4.6.2 IP‑CAN Session Modification; PCRF initiated

The PCRF may provide the following parameters in the Policy and Charging Rule Provision to the PDN GW (in addition to the parameters in clause 7.4.2): Authorized APN‑AMBR, User Location Information (if received from the BBERF), user GSG information (if received from the BBERF).

A.5.4.6.3 Void

Annex B (informative):
Void

Annex C (informative):
Void

Annex D (informative):
Access specific aspects (Non-3GPP)