Implementing Call Correlation

Mediation Engine Connector will correlate the call event when call events share a common call leg.

For each call leg that is a candidate for being the common call leg, the mediation engine runs a hash function over the INVITE message and stores it in the database together with a pointer to the call event of the call leg. A candidate call leg is a call leg where one of the two endpoints is a neighbor device. A neighbor device is a device configured on one of the other mediation engines, which is not marked as an External device.

When displaying the call event, each mediation engine is checked for an identical hash in their database. If true, the details of their call event are included in the display.

Note:

In Operations Monitor, the Mediation Engine Connector hash on P-Charging-Vector icid-value parameter and the Mediation Engine Connector hash search on all external legs settings affect the generation of hashes.

For more information on the Mediation Engine Connector hash on P-Charging-Vector icid-value parameter and the Mediation Engine Connector hash search on all external legs settings, see System Settings Summary in Operations Monitor User's Guide.

For example:

You have a device configuration that contains multiple sites containing one mediation engine for each site. Each site also contains several devices and all of the call's event traffic involved in one of these devices is sent to the site's mediation engine.

1. The call event leaves site A and directly enters site B, such as there is a call leg with one device on site A and one device on site B.
2. A device is configured as an Internal device on its site's mediation engine.
3. If there is direct traffic between a device on site A and a device on site B, the device on site B is configured as an External device on the mediation engine of site A. If there is direct traffic between a device on site B and a device on site A, the device on site A is configured as an External device on the mediation engine of site B.
4. Additional devices on a site can be configured as External devices on other sites mediation engines.

Configuration 1

The call event traverses five devices.

Devices DEV1 and DEV 2 are on site A, devices DEV 3, DEV 4, and DEV 5 are on site B. The following Internal assignments satisfy the requirement in point 2.

     DEV1 <--leg1--> DEV2 <--leg2--> DEV3 <--leg3--> DEV4 <--leg4--> DEV5
ME1  Internal        Internal
ME2                                  Internal        Internal        Internal

Configuration 2

If there is traffic from DEV2 to DEV3, add External devices as follows:

     DEV1 <--leg1--> DEV2 <--leg2--> DEV3 <--leg3--> DEV4 <--leg4--> DEV5
ME1  Internal        Internal        External
ME2                  External        Internal        Internal        Internal

Because leg2 goes from DEV2 to DEV3 the above configuration satisfies the requirement in point 1 for this call event. This is a functioning configuration.

Configuration 3

This can be extended to the following, which satisfies point 4.

     DEV1 <--leg1--> DEV2 <--leg2--> DEV3 <--leg3--> DEV4 <--leg4--> DEV5
ME1  Internal        Internal        External        External        External
ME2  External        External        Internal        Internal        Internal