Quick Setup Guide

Configuring and Troubleshooting VoIP Monitoring
40 November 2013
In Figure 18, the SPAN configuration (using egress-only) was changed to include the
port used to connect phones from the network cloud. Now we are able to see both
audio streams that make up the call between the internal agent and external caller.
Stream 3 is the agent's voice that exits the switch port connected to the external
network. Stream 2 is the caller's voice that exits the switch port connected to the
agent's phone.
In summary, any time two device ports are part of the same SPAN configuration, calls
between these two devices will result in packet duplication and bad audio quality
unless the SPAN is set to use ingress-only or egress-only packets.
Media Mixing
Issue: Failure to capture the Unified CM port can lead to loss of audio for conference
calls.
IP phone calls always consist of two audio streams, as shown in Figure 19, but calls
might contain more than two parties. When calls are conference calls, several
Figure 18. Ingress-only SPAN issue resolution