White Paper

White Paper

The sensor has two Fast Ethernet interfaces:

●

Management port

●

SPAN port

The sensor uses IEEE 802.3af standard Power over Ethernet (PoE) from the switch to which it

connects. When the Cisco 1040 Sensor boots up, it uses Dynamic Host Configuration Protocol

(DHCP) option 150 to retrieve its configuration and image files on a TFTP server. Similar to the way

that an IP phone registers with call manager a Cisco 1040 Sensor registers (using Skinny Client

Control Protocol [SCCP]) to the Service Monitor application. On the TFTP server, the Cisco 1040

first looks for its configuration file, named QOV[Cisco 1040 MAC address].CNF. If that file does not

exist, the Cisco 1040 looks for a file named QOVDefault.CNF. These CNF files provide the image

filename for the Cisco 1040 to download in addition to the Service Monitor IP addresses. The Cisco

1040 then downloads this image and registers to the Service Monitor, just like a phone registers to

a Cisco CallManager, using SCCP.

Then the Cisco 1040 Sensor utilizes the SPAN port on a switch to monitor the actual voice calls. It

collects voice impairment parameters such as jitter and packet loss from the RTP stream and

computes MOS values. The sensor works in passive mode to collect voice impairment statistics.

The sensor reports voice quality details and MOS values every 60 seconds, providing near real-

time voice quality measurement. Each Cisco 1040 can monitor 100 RTP streams with optimal

SPAN port configuration.

As shown in Figure 1, multiple sensors can be deployed in the network and configured to register to

the Service Monitor software component. Each instance of a Service Monitor software component

can manage up to 50 sensors and report call quality for 30,000 IP phones.

Figure 1. Multiple Sensors Register to Cisco Unified Service Monitor

Note: In Figure 1, the Cisco Unified Service Monitor and Cisco Unified Operations Manager

software instances coreside on a single machine. This type of deployment is supported for small

networks (fewer than 5,000 phones). For networks with more than 5,000 phones, the Service

Monitor and Operations Manager software must run on separate machines.