1.1 How Vivinet Diagnostics Works

Vivinet Diagnostics helps you diagnose and remedy problems on your VoIP network by gathering data from network devices and measuring simulated VoIP traffic. To pinpoint the source of a problem, it also runs a Path Trace between two selected devices on the network.

Vivinet Diagnostics contains a Knowledge Engine that stores data collected on your network from each Diagnosis you run. The Knowledge Engine compares the data it collects to its own information (or rules) about VoIP, network hardware and software, and typical VoIP trouble spots to analyze and diagnose a problem you report.

Before you run a Diagnosis, install NetIQ Performance Endpoints near soft phones, voice gateways, and servers in your network. Endpoints help gather diagnostic information and can send test VoIP traffic between Target Devices to uncover problems. For more information, see Section 1.7, NetIQ Performance Endpoints.

To run a Diagnosis, select two Target Devices you believe are located at or near the source of the problem. Target Devices can be endpoints, telephones, routers, or gateways. As the Diagnosis runs, Vivinet Diagnostics sends simulated VoIP traffic between the selected devices and shows you a path trace indicating exactly how the traffic is traveling from Point A to Point B. Vivinet Diagnostics takes measurements, checks call data records from VoIP network software, and uses its Knowledge Engine to arrive at a Diagnosis. A diagnostic report helps you analyze the problem and respond appropriately.

The following diagram illustrates how Vivinet Diagnostics works in a network in which Performance Endpoints are deployed:

Suppose a user has reported difficulty making a VoIP call over the corporate WAN between Seattle and Portland. The Vivinet Diagnostics Console is located at Corporate Headquarters in Raleigh. A switch in Portland is congested and has been identified as the source of the problem (as the error symbol indicates).

During a Diagnosis, Vivinet Diagnostics contacts the endpoint computers you identified as Target Devices. Test RTP traffic (Real-Time Transport Protocol, indicated by solid arrows in the diagram) that emulates real VoIP traffic is then sent between the endpoints. The endpoints take measurements of the simulated VoIP traffic, while the Vivinet Diagnostics Console uses the Simple Network Management Protocol (SNMP) to query hardware and software MIBs like that of the switch shown in the diagram.

Results are collected and sent back to the Console (dashed arrows), where they are analyzed to derive a Diagnosis. In this particular Diagnosis, the Console queries the router, the Portland switch, and both endpoints to gather data on dropped or deferred packets, delay, CPU and memory utilization, and other metrics.

If you do not install endpoints in the subnet where the problem occurred, the Console gathers call performance data using the following: