7.9 Procedures over Sy reference point

23.2033GPPPolicy and charging control architectureRelease 17TS

7.9.1 Initial Spending Limit Report Request

This clause describes the signalling flow for the H-PCRF to request the status of the policy counters available at the OCS, and to subscribe to spending limit reporting (i.e. to notifications of policy counter status changes) by the OCS. If the H-PCRF provides the list of policy counter identifier(s), the OCS returns the policy counter status per policy counter identifier provided by the PCRF. If the H-PCRF does not provide the list of policy counter identifier(s), the OCS returns the policy counter status of all policy counter(s), which are available for this subscriber.

The Initial Spending Limit Report Request includes all subscriber Identifiers associated with the UE available at the PCRF.

NOTE: In case the OCS returns the status of all available policy counters some of these may not be relevant for a policy decision (e.g. those used in a policy decision only when roaming).

Figure 7.9.1: Initial Spending Limit Report Request

1. The H-PCRF retrieves subscription information that indicates that policy decisions depend on the status of policy counter(s) held at the OCS and optionally the list of policy counter identifier(s).

2. The H-PCRF sends an Initial Spending Limit Report Request if this is the first time policy counter status information is requested for the user and the PDN connection. It includes in the request: the subscriber ID (e.g. IMSI) and , optionally, the list of policy counter identifier(s).

3. The OCS sends an Initial Spending Limit Report Response that contains a policy counter status, and optionally pending policy counter statuses and their activation times, per required policy counter identifier and stores the H-PCRF’s subscription to spending limit reports for these policy counters. If no policy counter identifier(s) was provided the OCS returns the policy counter status, optionally including pending policy counter statuses and their activation times, for all policy counter(s), which are available for this subscriber and stores the H-PCRF’s subscription to spending limit reports of all policy counters provided to the H-PCRF. Otherwise, the OCS returns the policy counter status of all policy counter(s), which are available for this subscriber.

7.9.2 Intermediate Spending Limit Report Request

This clause describes the signalling flow for the H-PCRF to request the status of additional policy counters available at the OCS or to unsubscribe from spending limit reporting. If the H-PCRF provides the list of policy counter identifier(s), the OCS returns the policy counter status per policy counter identifier provided by the PCRF.

NOTE: In case the OCS returns the status of all available policy counters some of these may not be relevant for a policy decision, (e.g. those used in a policy decision only when roaming).

Figure 7.9.2: Intermediate Spending Limit Report Request

1. The H-PCRF determines that policy decisions depend on the status of additional policy counter(s) held at the OCS or that notifications of policy counter status changes for some policy counters are no longer required.

2. The H-PCRF sends an Intermediate Spending Limit Report Request, optionally including in the request an updated list of policy counter identifier(s).

3. The OCS sends the Intermediate Spending Limit Report Response that contains the policy counter status, and optionally pending policy counter statuses and their activation times, per required policy counter identifier, and stores or removes the H-PCRF’s subscription to spending limit reporting by comparing the updated list with the existing H-PCRF subscriptions. If no policy counter identifier(s) was provided, the OCS returns the policy counter status, optionally including pending policy counter statuses and their activation times, for all policy counter(s), which are available for this subscriber and stores the H-PCRF’s subscription to spending limit reports of all policy counters provided to the H-PCRF.

7.9.3 Final Spending Limit Report Request

This clause describes the signalling flow for the H-PCRF to cancel the subscriptions to status changes for the policy counters available at the OCS.

Figure 7.9.3: Final Spending Limit Report Request

1. The H-PCRF decides that notifications of policy counter status changes are no longer needed.

2. The H-PCRF sends a Final Spending Limit Report Request to the OCS to cancel the subscription to notifications of policy counter status changes from the OCS.

3. The OCS removes the H-PCRF’s subscription to spending limit reporting and acknowledges the request by sending the Final Spending Limit Report Response to the H-PCRF.

7.9.4 Spending Limit Report

This clause describes the signalling flow for the OCS to notify the change of the status of the subscribed policy counters available at the OCS for that subscriber. Alternatively, the signalling flow can be used by the OCS to provide one or more pending statuses for a subscribed policy counter together with the time they have to be applied.

Figure 7.9.4: Spending Limit Report

1. The OCS detects that the status of a policy counter(s) has changed and the PCRF subscribed to notifications of changes in the status of this policy counter. Alternatively, the OCS may detect that a policy counter status will change at a future point in time, and decides to instruct the PCRF to apply one or more pending statuses for a requested policy counter.

2. The OCS sends the policy counter status, and optionally pending policy counter statuses and their activation times, for each policy counter that has changed and for which the H‑PCRF subscribed to spending limit reporting. Alternatively, the OCS sends one or more pending statuses for any of the subscribed policy counters together with the time they have to be applied.

NOTE: The values related to the status of the subscribed counter (e.g. valid, invalid or any other status) are not specified. The interpretation and actions related to the defined values are out of scope of 3GPP.

3. The H-PCRF acknowledges the Spending Limit Report and takes that information into account as input for a policy decision.

7.9.5 Sy Session Termination

This clause describes the signalling flow for the OCS to terminate the Sy session of a subscriber. This feature is optional.

NOTE 1: When the PCRF supports this procedure and a subscriber is removed from an OCS system, the existing Sy session of the subscriber can be terminated by this procedure.

Figure 7.9.5: Sy Session Termination

1. The OCS decides that the Sy session for a subscriber needs to be terminated.

2. The OCS sends the Sy Session Termination Request to H-PCRF to terminate the Sy session. The H-PCRF removes the Sy session context of the subscriber.

NOTE 2: The termination of the Sy session causes the H-PCRF to make the applicable policy decision and act accordingly, i.e. sessions on other interfaces such as the Rx or Gx interface will remain established, unless the policy decision causes their termination.

3. The H-PCRF acknowledges the termination of the Sy session of the subscriber by sending the Sy Session Termination Response.