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How to monitor voice traffic in Cisco Catalyst switches



These are the three ways to monitor voice traffic on Cisco Catalyst switches:

  • Through Switched Port Analyzer (SPAN) and Remote Switched Port Analyzer (RSPAN):

    With SPAN, packets are copied to a destination port for analysis. Cisco Catalyst switches support SPAN from local switches, where traffic is monitored through the SPAN of ports, VLANs, or EtherChannel technology.

    For SPAN and RSPAN configuration details, refer to Configuring the Catalyst Switched Port Analyzer (SPAN) Feature.

  • Through Network Analysis Module (NAM):

    Network managers can use NAM to set thresholds and alarms on various network parameters, for example, increased utilization, severe application response delays, and Voice over IP (VoIP) quality degradation. The use of NAM alerts network managers to symptoms like VoIP quality degradation, and helps avert potential problems. NAM provides comprehensive views on applications, hosts, VoIP, and quality of service (QoS) to isolate faults or malfunctions in the network. NAM can analyze VoIP traffic flows in real time to collect valuable information, including call setup details and VoIP quality metrics.

    NAM identifies violations of QoS policies, and leads to effective deployment of QoS for VoIP and other critical services. NAM supports the Differentiated Services (Diff-Serv) Monitoring MIB, which monitors traffic through differentiated services code point (DSCP) allocations that QoS policies define.

    For more information, refer to Cisco Catalyst 6500/7600 Network Analysis Module Deploy Guide.

  • Through CiscoWorks Internetworks Performance Monitor (IPM):

    IPM provides several default Enhanced User Datagram Protocol (UDP) operations to measure performance between a source and target. The Enhanced UDP operation for VoIP generates synthetic UDP traffic to measure round-trip latency, packet loss, and jitter in IP networks. The Enhanced UDP operation sends a defined number of packets of a defined size from the source router to a target router with a defined inter-packet delay. Both the source router and the target must run Cisco IOS   Software Release 12.1 or later, and the target must have the SA Agent Responder enabled.

    For more information, refer to Measuring Network Performance for Voice Over IP section of document Using IPM to Measure Network Performance.

    For more information, refer to the Measuring Network Performance for Voice Over IP section of Using IPM to Measure Network Performance.

Device connected to switch

Cisco IP Phone