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Configure Routers to Send Link Statistics through BGP-LS

Starting from Paragon Automation Release 21.2, you can use BGP-LS to obtain information about the link delay and link delay variation (variation in the measured delay between consecutive readings) from a network. Earlier, the link delay information was obtained from RPM probes configured on the routers.

You can view the link delay statistics in the Paragon Automation GUI as follows:
  • Right-click a link label in the network topology (Network > Topology) and select Measured Delay A::Z . The measured delay is listed on the links as shown in Figure 1.
    Figure 1: Measured Link Delay Indicated on Links in the Network Topology
  • The Measured Delay A and Measured Delay Z columns in the Links tab of the Network Information table display the measured delay on respective ends of the link; see Figure 2.
    Figure 2: Measured Delay Displayed in the Network Information Table
Note:

In Paragon Automation Release 21.2, you cannot view the Interface Delay graph (accessed from Link > View > Interface Delay in the Network Information table) that displays the variation of the measured link delay over a period of time.

The path computation element (PCE) in Paragon Pathfinder uses the measured link delays to compute the end-to-end LSP delay as a sum of all link delays in an LSP path. If a maximum delay is configured for the LSP and if the computed link delay violates the configured maximum delay, the PCE computes and reroutes the LSP through a path that has a link delay within the configured maximum delay.

Note:

You can configure Juniper Networks routers to send measured link delay through BGP-LS only if Junos OS 21.3 or a later version is running on the router. Also, the routers send the measured delay and delay variation only when using the IS-IS protocol on a point-to-point link.

To configure a Juniper Networks router to advertise the measured delay and delay variation on a link through BGP-LS:

  1. Enable TWAMP on the routers at the ends of the link:
  2. On each router, configure the interfaces on which you want to measure the delay. For example:
  3. If RPM probes are enabled on the routers, disable RPM probes to ensure that the routers do not send link delay statistics obtained through RPM probes:
    Note:

    Refer to Configure Routers to Send JTI Telemetry Data and RPM Statistics to the Data Collector for the RPM probes that might be configured on the router.
  4. (Optional) View the measured delay in the TED database and cRPD by using the following commands:
    • To view the measured delay in TED database of a node, execute the following command in the Node:

      The output lists the average delay, minimum delay, maximum delay, and delay variation as follows:

    • To view the measured delay received by cRPD, execute the following command in cRPD:The output lists the average delay, minimum delay, maximum delay, and delay variation as follows:

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