The SIP PDUs (Protocol Data Units) are captured at the application layer and continuously streamed to the monitoring server. Configurable Headers are included in SIP PDUs to enable the monitoring server to decode SIP signaling properly. Headers have source and destination IP address/Port information along with additional information which is configurable – this information is needed by the monitoring server in order to correlate the stream received. The packet is captured at ingress leg without SMM applied and with SMM applied on egress leg, which is essentially what is being sent on the wire. To lessen performance impact, all socket-management activities to the monitoring server use a separate SIPSM (SIP Signaling Monitor ) process receives all signaling packets from the SIP Signaling Gateway (SIPSG) and streams to the configurable external monitoring server either over UDP or TCP. |