White Paper

White Paper

Operations Manager provides a powerful product for monitoring and troubleshooting voice quality

problems.

Placement of Cisco 1040 Sensors

The Cisco 1040 Sensor is FCC Class B certified and can be deployed in a wiring closet or on a

desk. The Cisco 1040 uses the SPAN port on the switch to monitor the RTP stream. As shown in

the following diagram, the sensors are deployed as close to the IP phone as possible so that the

voice quality measurement will be close to what the user experiences. The sensor reports voice

quality measurements every 60 seconds. For each conversation, there are four RTP streams: two

each from originating and terminating phones. In the default SPAN port configuration, Service

Monitor receives four MOS values every 60 seconds for each conversation. As discussed in the

previous section, of the four RTP streams, two provide meaningful statistics; hence, the MOS value

calculated for the interesting RTP stream is of importance and should be considered for further

analysis.

Figure 3. Cisco 1040 Placement

The number of sensors per switch depends on the following:

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Type of switch

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Type of customer

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Number of simultaneous calls

The type of switch determines the number of SPAN destination ports that can be configured on the

switch. Modular switches such as the 65xx support two SPAN destination ports with different

source ports. Most of the fixed configuration switches support a single destination port. On the

modular configuration switches, you can have two sensors deployed on the same switch, and on

the fixed configuration switch, you can have a single sensor deployed.