The Diameter Message Copy feature allows users to forward a copy of a Diameter Request message received by or routed through the Diameter Signaling Router to a Diameter Application Server (DAS peer). This capability is triggered based on the CPA configuration.
A user can specify a triggering condition or rule, and when a Diameter Request meeting the triggering condition is received by the DSR, the message is marked as ready to copy by the application as it is processed. When the response to the request (the answer) is received, if the answer contains the correct result code as specified by the system-wide configuration, the resulting action is executed. In the case of Message Copy, the action is to copy the Request and send the copy to a DAS peer. Message Copy copies only the Diameter portion of the Request that matches a triggering condition; thus, the transport and IP layers are not copied. Lower layer protocols that do not contain Diameter Requests are not copied; thus, Message Copy does not implement a port mirror that replicates everything received on the wire on a specific port to an egress port.