CUPS supports multiple Diameter Routing Agents (DRA) to prevent the abort of pending Credit Control Request–Update (CCR-U) requests from previous Reauthorization Requests (RAR) with a different host or peer on the Gy interface.

P-GW accepts different rating-groups (RG) from different peers by configuring the diameter pending-ccau allow-on-rar-peer-switch CLI command in the ACS configuration mode. This command allows you to configure the DCCA client to prevent the abort of a pending CCR-U request.

For more information on the multiple DRA support in P-GW, see the Support for Multiple DRA over Gy Interface chapter in the P-GW Administration Guide.

This section describes how the multiple DRA feature works in CUPS.

P-GW and CUPS handle the collision scenarios differently. In legacy P-GW, each CCR-U with FORCED REAUTHORIZATION is sent to the corresponding DRAs.

In CUPS, the user plane fetches every CCR-U that is sent along with the current usage report. During collision, if more than one specific RAR is received at the same time from different DRAs for the respective rating groups, the control plane marks the Gy-URR buckets, and sends Sx Session Modification Request to the user plane. The user plane sends back the current usage reports to the control plane for the requested Gy-URR bucket in Sx Session Modification Response. If RAR is received from different DRAs, the peer switch happens. In CUPS, each CCR-U with FORCED REAUTHORIZATION for the requested rating groups is sent to the peer DRA of the latest path switched.

The following call flow illustrates how P-GW accepts both RGs from different peers.

To configure the handling of multiple RAR requests involving multiple DRAs, use the following configuration:

configure 
   context context_name 
   active-charging service acs_service_name 
      credit-control [ group cc_group_name ] 
         diameter dictionary dictionary 
            [ no ] diameter pending-ccau allow-on-rar-peer-switch 
            end 

NOTES:

• diameter dictionary dictionary : Set the diameter dictionary to handle different DRAs.

  For example: diameter dictionary dcca-custom-26

• diameter pending-ccau allow-on-rar-peer-switch : Allow the DCCA client to prevent the abort of pending CCAU requests.

• no diameter pending-ccau allow-on-rar-peer-switch : Disable the DCCA client from preventing the abort of pending CCAU requests.

This section provides the monitoring and troubleshooting information for the multiple DRA feature.