The Communication Agent

The Communication Agent (ComAgent) enables reliable communication between Policy and Charging DRA and SBRs and among SBRs in a scalable and high available PCA network. Figure 1 depicts the communication paths between the Policy and Charging DRA, the SBR, and their ComAgents, and the communication paths between the ComAgents.

Note: The DTL uses ComAgent to transmit TTRs to DIH. The Diameter Troubleshooting Layer (DTL) is a component of the Diameter plug-In architecture that transmits TTRs to DIH.

Communication between ComAgents, Policy DRA, and SBR

The ComAgent Direct Routing service, HA service, and the MP Overload Management Framework are used by the Policy and Charging DRA and SBR for communication and for SBR congestion control. (See SBR Congestion for information about the MP Overload Management Framework.)

Policy and Charging DRA automatically establishes TCP connections between all of the servers that need to communicate with the database. The following connections are established:

All DA-MPs in the network connect to all binding SBRs in the network.
All session SBRs in the network connect to all binding SBRs in the network
All DA-MPs in a mated pair connect to all session SBRs in the mated pair

You can view and manage these connections using the ComAgent Connection Status GUI at the NOAM: Communication Agent > Maintenance > Connection Status. There is also a ComAgent HA Service Status, but the same information can be obtained from the Policy and Charging > Maintenance > SBR Status page.