Cisco Prime Collaboration Assurance Guide - Advanced, 10.0
Media Path Analysis
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Media Path Analysis

Media Path Analysis

This section contains the following:

Analyzing Media Paths Using IP SLA

To start a proactive troubleshooting workflow:

Before You Begin

You can use this feature only if you have enabled the Cisco IOS IP Service Level Agreements (SLAs) on your network devices.

Cisco IOS IP SLA allow you to monitor network performance between Cisco devices (routers or switches). You must configure Cisco IOS IP SLAs Source and Responder in your network. You can verify whether the IPSLA responder feature is enabled on the device, using Prime Collaboration Assurance Device Work Center.

To understand and deploy the IP SLA on your network devices, see the IP Service Level Agreements (IP SLAs) technology page on Cisco.com.


    Step 1   Choose Operate > Diagnose > IP-SLA Diagnostics.
    Step 2   Perform the following:
    1. Select the IP SLA source device from where you want to start the IP SLA testing.
    2. Select the IP SLA responder IP device, which is the IP SLA destination.
    3. Select the specific IP address of the responder IP device (applicable if your IP SLA destination device is configured with more than one IP address).
    4. Select the application for which you want to test the network performance.
      Note   

      voice-service dsp-reservation <percentage> command must be configured on the router that acts as IP SLA initiator, to collect IP SLA statistics from the router.

    5. Enter the IP SLA test life (in minutes).
    Step 3   Click Start.

    IP SLA Test Result

    Based on the IP SLA Test Life (Minutes) value that you enter, the IP SLA tool will generate the traffic for that duration. The IP SLA Test Result display data for:
    • Latest result—Last time interval for which the operation was monitored. This depends on your configuration for frequency of monitoring on the device. Cisco IOS IP SLAs consumes CPU and memory. Most deployments use five-minute intervals, but some are one minute apart while others are 15 minutes apart.
    • Last one hour aggregated result—Aggregated result for the last one hour.
    • Flow Statistics for only video flow path is displayed in the path topology, if the device is configured as a mediatrace responder.
    The IP SLA Test Result includes:
    • Test Duration—Time interval for which the packets were monitored in seconds.
    • Number of Tests Run—The number of times the IP SLA operation was run. This is based on the frequency of monitoring that you have configured on the device.
    • One Way Latency—Average, minimum, and maximum latency values. These values are measured by sending RTP packets to IP SLAs Responder. The RTP (Real-Time Transport Protocol) data stream is then looped back from the destination, to the source gateway.
    • Packets Lost—Number of packets lost. The source-to-destination value is measured by sending RTP packets to the IP SLAs Responder. No values are obtained from the digital signal processors (DSP) for this measurement.
    • Inter-Packet Delay Variation (IPDV) (RFC 5481) Positive and Negative Jitter—Average, minimum, and maximum jitter values as calculated in RFC 5481.
    • Last Updated—The time when the data was last updated.

    The IPSLA result also provides details on the path through the Path Assessment tab. You can view the proactive troubleshooting summary information for testable devices, nontestable device, mediatrace-enabled devices, devices with packet loss threshold violation, devices with jitter threshold violation, and devices with DSCP violation.

    A set of tests are run for the devices determined during proactive troubleshooting. To start the Path Assessment test, click Path Assessment Tests, after the proactive troubleshooting is complete for the session. For more information, see Path Assessment.

    If the troubleshooting IP SLA statistics is not available, Prime Collaboration supports application diagnostics to diagnose the issues and understand the root cause and recommendation.
    Figure 1. IPSLA Test Result Failure



    You must click Run Diagnostics. A message pops up stating the root cause and recommendation. After you run diagnostics, Prime Collaboration can diagnose if:

    • The device supports IP SLA video operations.
    • Prime Collaboration has CLI access to the device.
    • IP SLA configuration is provisioned for the session running.
    • The To device has IP SLA responder role configured.
    • NTP clock is synchronized.
    • The To device is reachable via the From device.
    • voice-service dsp-reservation command is configured on the From device, if it is a router.
    Figure 2. IP SLA Diagnostics Root Cause and Recommendation



    Analyzing Media Paths Using VSAA

    To perform media path analysis:

    Before You Begin

    Prime Collaboration has the capability to facilitate the readiness assessment of a network to deploy Cisco Video or TelePresence systems. The Video SLA Assessment Agent (VSAA) is used in Prime Collaboration to provide network path characteristics (that is, latency, jitter, and packet loss) metrics before deploying or upgrading Cisco Video, TelePresence, or IP Video Surveillance (IPVS) systems and site extensions.

    The agent helps to determine network issues proactively, facilitating the expected rich quality and experience of Cisco TelePresence systems after its deployment. The benefits of the VSA Agent include accelerated Cisco TelePresence systems deployment and reduction in effort and time through automation of the assessment process and reporting.

    You can download the VSA Agent software from the Prime Collaboration software download site on Cisco.com. See Video SLA Assessment Agent 3.1 Installation Guide for the installation guidelines.

    Verify that the VSA Agent is up and running at the two endpoints, and synchronized to the NTP server.


      Step 1   Choose Operate > Diagnose > Media Path Analysis.
      Step 2   Enter the required assessment details.
      Step 3   Enter the profile details.
      Step 4   Click Start.

      Table 1 Profile Details

      Field

      Description

      Profile

      Displays the profile settings you want to assess. RTP packets sent will be of based on the device type.

      Count

      Number of devices or streams you want to add to the network. You can add upto five devices.

      DSCP

      DSCP value indicates priority to traffic quality. The highest quality DSCP value is selected to ensure good quality video streaming.

      You must use CTS1000 profile to deploy CTS 500 and 1000 and CTS3000 profile to deploy CTS 3000. You can create, edit, and delete profiles.

      VSA Agent Assessment Results

      For the individual streams, you can view the topology (layer 2 and layer 3) for the selected direction between endpoints in the Troubleshooting tab.

      You can view the detailed troubleshooting workflow status for the top level and the individual streams using the Log tab. The Medianet Path View contains output from each mediatrace enabled device. The VSA Agent Assessment result also provides details on the path through the Path Assessment tab. You can view the troubleshooting summary information for testable devices, nontestable device, mediatrace-enabled devices, devices with packet loss threshold violation, devices with jitter threshold violation, and devices with DSCP violation.

      A set of tests are run for the devices determined during troubleshooting. To start the Path Assessment test, click Path Assessment Tests, after the proactive troubleshooting is complete for the session. For more information, see Path Assessment.

      The Test Result tab displays the following charts. For these charts, only the results of last twenty tests are displayed.

      Test Summary

      Figure 3. Test Summary



      Peak-to-Peak Jitter

      Figure 4. Peak-to-Peak Jitter Graph



      Packets Lost

      Figure 5. Packets Lost Graph



      Latency

      Figure 6. Latency Graph



      Managing a Video Test Call

      You can create point-to-point video test calls between two video endpoints in managed state, to test your network. You can see events and alarms, session statistics, endpoint statistics, and network topology with medianet statistics like other calls. Only the CTS, C and EX series codecs are supported for this call.


      Note


      • This feature is not supported for E20 codec series.
      • To use this feature, CLI credentials must be added for the endpoints.
      • Ensure that the endpoints are registered and JTAPI is enabled for endpoints (if they are registered to CUCM).

      Table 2 Managing a Video Test call
      Task Description
      • Start a video test call from Endpoint Diagnostics (Under Operate)
      • Start a video test call from Session Diagnostics (Under Operate)
      Select the video endpoints, and click Video Test Call, to create a test call between two selected endpoints.
      Note   
      • This button gets enabled only after you have selected two video endpoints.
      • You cannot create a video test call by selecting more than two endpoints.

      or

      Select a particular session on the Session Diagnostic page, and click Video Test Call, to create a test call for that scheduled session.
      Note   

      This button gets activated only after you select a scheduled session. To see the list of the list of scheduled sessions, filter for scheduled sessions. Remember to select a session for a future time and date only.

      The Add Test Call pop up window appears, where you can click on the IP address of the endpoint to launch its application. The default option is to run the test call immediately but you can schedule the call also.

      For CTS endpoints select the SIP protocol only. For Ex and C Series endpoints you can choose between H.323 and SIP protocols, provided these endpoints are registered using these protocols. When you click the Add Call button, a message appears to notify you that the call has been added successfully.

      The scheduled call details can be seen on the Session Diagnostics page. You can see events and alarms, session statistics, endpoint statistics, and network topology with medianet statistics like other calls. This information is available for completed test calls also. You can stop the call immediately if it causes a problem on the network.

      Stop a running video test call

      You can stop a video test call which is in progress if it hampers your network. To stop a call, select the test call from the Sessions Diagnostic page, by setting the filter to Test Call Sessions. Hover around the session subject to launch the 360° Session View, and click the Stop Call icon to stop the in progress video test call.

      Test call lasts for around 5 minutes, after which it automatically stops.

      Edit a scheduled video test call from Video Test Call Configurations page

      Administration > System Setup > Diagnostic Test > Video Test Call Configurations

      You can also view or delete video test calls from the same page.

      To edit a video test call, click Edit, and reschedule or run the call immediately by clicking Save. A message appears to notify you that the call has been modified successfully.