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Reroute LSPs Automatically

Paragon Pathfinder can automatically reroute LSPs based on delay, packet-loss threshold, and link utilization in LSPs . For example, you can configure Paragon Pathfinder to reroute an LSP when the utilization percentage of a link through which the LSP traverses reaches 75 percent of the link capacity. See Reroute LSP Overview for more details.

To reroute LSPs, Paragon Pathfinder uses the variables listed in Table 1.

Table 1: Parameter for Rerouting LSPs Automatically
Parameter Description Range


Interval in minutes during which Paragon Pathfinder periodically checks the delay, packet loss, and link utilization in LSPs.

Paragon Pathfinder reroutes the LSPs when the measured values for delay, packet loss, or link utilization in an LSP exceeds the corresponding thresholds configured in Paragon Automation. If you do not specify an interval, Paragon Pathfinder does not reroute the LSPs when the measured values exceed the configured thresholds.

1 through 300

Maximum delay

Defines the delay (in milliseconds) at which Paragon Pathfinder must reroute an LSP. For real-time traffic such as VoIP, set the maximum delay to less than 150ms.


Link utilization threshold (link-utilization-threshold)

Threshold value (in percentage) for link utilization. When traffic on a link exceeds this value, Paragon Pathfinder triggers the rerouting of LSPs. If a threshold is not specified, LSPs are not rerouted. If 0 is specified, links are blocked (no traffic is allowed through the links) and the LSPs are not rerouted.

Range: 0 through 100

Packet loss threshold (packet-loss-threshold)

Threshold value (in percentage) for packet loss on all links. If the packet loss on a link exceeds this value, the link is considered unstable, and the path computation server (PCS) reroutes the LSP and triggers a maintenance event on the link. If you do not specify a value or if you specify 0, the PCS does not reroute the traffic to another LSP in case of packet loss.

Range: 0 through 100

To reroute LSPs automatically:
  1. Do one of the following on the Topology page (Network > Topology).
    1. To add a tunnel (LSP), click Add icon (+).
      The Add Tunnels page appears.
    2. If you are editing an existing tunnel, click Edit icon (pencil).
      The Edit Tunnels page appears.
  2. On the Constraints tab of the Add Tunnels page or Edit Tunnels page, configure Maximum Delay. See Add a Single Tunnel.
  3. In the Analytics section of the Path Computation Server settings on the Pathfinder page (Configuration > Network Settings > Pathfinder Settings), configure the following parameters:
    • reroute-minimum-interval

    • link-utilization-threshold

    • packet-loss-threshold

    See Modify Pathfinder Settings From the GUI.

  4. To view LSPs that might have been rerouted:
    1. Right-click anywhere on the Topology page and select Timeline.

      The timeline is refreshed every two minutes and displays network events in a chronological order. Rerouted LSPs are displayed when you right-click Link Down events.

    2. Select the LSP and click View > Tunnel Traffic to ensure that traffic is flowing smoothly through the LSP, and click View > Delay to ensure that delay is within the acceptable limits.