Voice monitoring and recording are features of the IP Integrated
Contact Distribution (ICD) Cisco Supervisor Desktop client. These features
allow a supervisor to silently monitor and record the phone call of an agent.
This document describes the reason that monitoring and recording of IP calls on
two different Cisco Catalyst 6509 switches fails with distorted voice in a
Cisco IP Contact Center (IPCC) environment.
Readers of this document should be knowledgeable of the
The information in this document is based on the software
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
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When the monitoring and recording failure occurs, the topology is set
up, as shown in Figure 1.
Figure 1: Topology
When performing voice monitoring and recording between two agents on
the same Catalyst 6509 switch, the voice playback is
normal. However, when performing voice monitoring and recording between two
agents on different Catalyst 6509 switches, the voice
playback is slow and slightly distorted.
This problem is a Catalyst 6509 Remote Switched Port Analyzer (RSPAN)
configuration issue. When configuring RSPAN, the original RSPAN setup is VLAN
RSPAN. Since trunk port is part of the VLAN, it also monitors and records all
traffic over the trunking port. This creates a packet duplication problem in
the process of voice monitoring and recording.
To fix the duplicate-packet problem, change the RSPAN configuration
from VLAN RSPAN to port RSPAN. Ports for CallManager, IPCC Express servers and
agents (except trunking ports) should be configured with port SPAN. When
configuring the port, configure either transit (Tx) or receive (Rx), but not