White Paper

White Paper

Service Monitor satisfies most quality-monitoring requirements for enterprise IP telephony.

Deployment strategies include:

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Strategic monitoring: The Cisco 1040 Sensor is installed to continuously monitor IP

phones at some or all locations in the managed environment. Depending on monitoring

goals, significant coverage of all or most sites could be included, or by using sampling

techniques, representative sites would be selected for monitoring and would determine the

location of the Cisco 1040 sensors. Service Monitor can scale to support up to 500 RTP

streams a minute total from multiple Cisco 1040 sensors and can provide real-time alerting

on call quality issues as well as providing information that can be used to evaluate general

service levels and to validate performance of SLAs.

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Tactical monitoring: Cisco 1040 sensors can be inexpensively shipped overnight to a site

(such as a branch office) that has voice quality concerns or problems. Once it is installed, it

can immediately begin monitoring and assessing the quality of IP-based calls without

elaborate setup or complicated installation. The Cisco 1040 Sensor is FCC Class B

compliant and can easily be installed in any office environment.

Figure 2 shows centralized Cisco Unified Communications Manager deployment with one remote

branch office connected through a WAN circuit. To monitor voice quality for calls across the WAN

circuit, two Cisco 1040 Sensors must be deployed as shown. The key is to deploy the sensors

switch as close to the IP phone as possible. In most cases, the sensors will sit on the access layer

switch in the campus.

Figure 2. Centralized Cisco Unified Communications Manager Deployment

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For each phone, there are transmit and receive RTP streams.

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For the RTP stream originating from Phone A (TX RTP stream), the segment between 1 and

2 in Figure 2 experiences the least impairment, and the probability of voice quality

degrading in this segment is slim to none. The RTP stream between segments 2 and 3

traverses several network devices and is prone to network conditions.

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The previous statement is also true for RTP streams originating from Phone B.

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For the sensor on the left in Figure 2, you can safely ignore the RTP stream from Phone A