Support for PDSN handoffs in SBBC

• Both Simple IP and Mobile IP supports AGW ↔ AGW (PDSN) fast handoffs – Mobile IP supports Dormant

Handoffs– Bearer connections (A10,

A11) moved between AGWs during handoff

– This capability is not required for GGSNs

• What about cross technology handoffs? e.g. (HRPD ↔ 1X and Rev A ↔ Rel 0)

Typical Handoff Signaling (Inter PCF- Different PDSN)

Inter-PCF Handoff (Dormant or Active) - Different PDSN

This kind of handoff is indicated to the PDSN by receipt of an A11 Registration Request containing the PANID and CANID. It also includes the Mobility Event Indicator and Accounting Data (R-P Session Setup Air-link Record). From the perspective of High Availability, this looks like a new session establishment on the newly active PDSN and a 'regular' session termination on the old PDSN.

Background info

Background info

Background info

Background info

3. The PCRF translates any updated authorized application level QoS parameters received from the AF to the corresponding allowed QoS parameters for use by the AGW. The PCRF may apply local network policy that may affect the allowed allocation of bearer resources. If the application level QoS requested by the AF is allowed by local policy, the PCRF confirms this back to the AF.

4. Based on the updated information, the PCRF formulates or modifies appropriate charging rule(s) for the flows. If the PCRF has previously provided authorization regarding these flows, the PCRF then passes these updated mapped/translated authorized QoS parameters and charging rules to the AGW.

5. The AGW confirms receipt of the updated information to the PCRF. The AGW saves the updated information and uses these current QoS values to compare with subsequent MS requests for QoS bearers.

2. The MS initiates the establishment or modification of the required bearer resources. As part of the establishment or modification procedure the MS passes the binding information that identifies the application session flows and may identify the authorizing entity.

3. Steps 3 through 7 are only performed if the AGW determines that authorization is needed from the PCRF. The AGW determines that the resource establishment or modified requires authorization and initiates an Authorization Query to an appropriate PCRF and includes the binding information with authorizing entity identity information provided by the MS at registration time or in the bearer establishment/modification request. The Authorization Query may include zero or more application flows.

4. If the PCRF determines that authorization requires information from a related AF, the PCRF contacts the AF and includes the binding information. Otherwise, the procedure continues at step 6b below.

5. The AF responds by returning information regarding the authorized QoS and other information for the session associated with the flows. The AF may also include in the response, an authorization to open the gate with no further messages. This flow assumes that the gate is authorized to be opened at this time.

6a. The PCRF translates the authorized application level QoS parameters received from the AF to the corresponding allowed QoS parameters for use by the AGW.

6b. The PCRF may apply local network policy that may affect the allowed allocation of bearer resources. The PCRF formulates or modifies appropriate charging rule(s) for the flows. The PCRF then passes these mapped/translated Authorized QoS parameters and charging rules to the AGW.

7. The AGW compares the requested QoS parameters received from the MS to the authorized QoS parameters received from the PCRF. If the requested QoS parameters are within the limits established by the authorized QoS parameters, the AGW replies with a Resource Establishment Confirmation indication to the MS.

How does the PCRF know that subsequent bearers will be requested. Does this mean that PCRF is not applicable on RAT without supplementaty bearers

This implies that Bearer only (no AF required) is permitted.

How can the PCRF know that authorization requres information from the af

How does the PCRF know that a giver bearer creation needs authorization from the PCRF

Figure 7.1b – AGW initiated SBBC authorization at MS Initiated Request for Bearer Establishment/Modification

Figure 7.2 – AF Initiated Authorization Update Even if the Bearer never comes, new charging rules can be pushed

PreviousAGW

New AGW PCRF

NewPCF

PreviousPCF

A11 Registration Request

MS

PCRF Sees Duplicate Authorization and

implements handoff

SBBC Authorization Query

Bearer Authorization and

charging rules

R-P Session ExpiresTerminate Remaining Bearers and Charging rules. Terminate IP Charging Rules

Delete MS Session and all Subsessions

New Bearers should be authorized (e.g. admitted) and new charging rules may apply

PCRF Loads IP QoS and Charging

Rules

A11 Registration Reply

A11 Registration Update

SBBC Terminate Charging Rules

SBBC Terminate Bearer

A11 Registration RequestSBBC Authorization

Query

Re-negoitiate PPP and Mobile IP

Bearer Authorization and

charging rules

* Not all A11 signalling messages shown

AF

Handoffs Where Each AGW is Attached to a Different PCRF

AF AF

PCRF PCRF

AGW AGW• There is no assurance that an MS cannot handoff to an AGW/PCRF that is not attached to the MS’s AF

• There is no way to ensure that MS/AGW is on the same PCRF as the AF

• When an AF is attached to multiple PCRFs there is no way for the AF to determine the current AGW/PCRF for the MS

• PCRF/AGW may need to transfer gate information to new PCRF/AGW in handoff situation

• Recommend contribution for Service PCRF (S-PCRF) and Access PCRF (A-PCRF) similar to TISPAN model

– Provides Scalability– Support Fixed Mobile Convergence– Resolve inter PCRF handoff problems– Can be implemented as a Redirect server for scalability and

performance

AF AF

A-PCRF

AGW AGW

S- PCRF

A-PCRF A-PCRF

Cable/DSL