If a match is found, the specified Peer Route Table is used.
If the ingress Peer Node is configured as "Not Selected", that entry is skipped and the Application Ids configuration is checked.
If no match is found in the Application-Ids configuration, the Default Peer Route Table is used.
If no Peer Routing Rule matches in the Default Peer Route Table, PCA will attempt to route the Request using Destination-Host routing (for example, to a connection or Alternate Implicit Route List associated with the destination Peer Node).
The Peer Route Table to use for new bindings is specified in the Policy and Charging > Configuration > Policy DRA > Site Options GUI page on the SOAM at each site.
If the Peer Route Table for new bindings is set to "Not Selected", the Diameter Routing Function uses the precedence described in Peer Routing.
Sessions for subscribers that are already bound to a PCRF must be routed to the bound PCRF, or to a PCRF that shares state with the bound PCRF if the PCRF supports sharing of policy state. For existing bindings, no Peer Route Table is configured in the PCA application Site Options. Instead, the Diameter Routing Function uses the precedence described in Peer Routing.
In order to route Requests initiated by the PCRF, routing must be configured such that Requests from any PCRF can be routed to any Policy Client in the network. This type of routing is used to route RAR and ASR requests. For Requests from PCRFs to Policy Clients, no Peer Route Table is configured in the PCA application Site Options. Instead, the Diameter Routing Function uses the precedence described in Peer Routing.
In-session Requests are Requests within a Diameter session other than the Request that established the Diameter session. CCR-U, CCR-T, and STR are all examples of in-session Requests. In-session Requests are routed using the predefined precedence of Peer Route Tables described in Peer Routing.
All Diameter Answer messages are routed over the same path on which the Request was routed, using hop-by-hop routing. No routing configuration is necessary to route Answer messages.