Cisco Cisco Agent Desktop 8.5 Referências técnicas
References
November 26, 2003
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Appendix C Using Multiple NICs with the VoIP Monitor Service
C.1 Overview
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.
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 config-
ured 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.
ured 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 nor-
mal 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:
for both receiving and sending traffic. There are switches that do not allow nor-
mal 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.
and sniffed RTP streams, connected to a normal switch port not monitored
by the above-mentioned SPAN port.
C.2 Limitations
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.
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.
to TCP/IP. Make sure the sniffing card is bound to TCP/IP.
C.3 Issues
The VoIP Monitor service does not specify which NIC should be used when
sending out packets. This is not a problem when using a single NIC for both
sniffing and normal traffic. With two NICs, however, normal traffic should be
restricted so that it does not go through the NIC used for sniffing. Otherwise,
the sniffed RTP streams of a currently-monitored call might not reach the super-
visor because the SPAN destination port does not allow outgoing traffic.
sending out packets. This is not a problem when using a single NIC for both
sniffing and normal traffic. With two NICs, however, normal traffic should be
restricted so that it does not go through the NIC used for sniffing. Otherwise,
the sniffed RTP streams of a currently-monitored call might not reach the super-
visor because the SPAN destination port does not allow outgoing traffic.
To resolve this, use the route command to customize the static routing table so
that normal traffic does not go through the sniffing NIC. Contact your network
administrator for details.
that normal traffic does not go through the sniffing NIC. Contact your network
administrator for details.