Cisco Cisco Agent Desktop 8.5 Guia Da Instalação

The VoIP Monitor service sniffs RTP traffic from the network and sends it to 
registered clients. This requires support from the switch to which the service is 
connected. 

The VoIP Monitor service must be connected to the destination port of a configured 
SPAN/RSPAN. Any traffic that crosses the SPAN/RSPAN source ports is copied to 
the SPAN/RSPAN destination port and consequently is seen by the VoIP Monitor 
service. 

Not all Catalyst switches allow the VoIP Monitor service to use the SPAN port for 
both receiving and sending traffic. There are switches that do not allow normal 
network traffic on a SPAN destination port. A solution to this problem is to use two 
NICs in the machine running the VoIP Monitor service:

■

One NIC for sniffing the RTP streams, connected to the SPAN port

■

One NIC for sending/receiving normal traffic, such as requests from clients 
and sniffed RTP streams, connected to a normal switch port not monitored by 
the above-mentioned SPAN port.

Since Cisco CallManager does not support two NICs, using multiple NICs works 
only in configurations where CallManager is not co-resident with the VoIP Monitor 
service.

SplkPCap 3.0, the packet sniffing library, works only with NICs that are bound to 
TCP/IP. Make sure the sniffing card is bound to TCP/IP.