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LSP Stuck in PENDING or PCC_PENDING State

Problem

The Controller Status of the LSP may display a pending status. This error may persist even after the topology server (Toposerver) marks the nodes as PCEP-enabled and you provision the label-switched path (LSP). The Controller Status (as seen in the Tunnel tab of the network information table) displays the word PENDING or PCC_PENDING.

Solution

Through the provisioning process, an LSP has various provisioning states that indicate the status of provisioning. The Controller Status column on the Tunnel tab of the network information table displays these provisioning states. The most common LSP states are PENDING and PCC_PENDING.

The following sequence describes what happens behind the scenes:

  1. To provision an LSP, the Path Computation Server (PCS) computes a path that satisfies all the requirements for the LSP. The PCS then sends a provisioning order to the Path Computation Element (PCE) server.

    Following is an example of the log message that appears in the PCS log while this process is taking place:

    Note:

    The logs that you view may differ from the logs in this document. The logs change based on the installed version of Paragon Automation.

  2. The LSP's controller status is PENDING. This status means that the PCS has sent the provisioning order to the PCE server, but the PCS has not received an acknowledgment yet. If an LSP remains in the PENDING state, it suggests that the problem lies with the PCE server.

    You can identify the problem by viewing the logs for the PCE server.

    To view the logs for the PCE server:

    1. Use your server credentials to log in to the primary node of Paragon Automation.

    2. From the primary node, use the following command to obtain the name of the pod in which the PCE server process runs:

    3. Log in to the PCE server pod by using the following command:

      In the command, ns-pceserver-pod-name is the name of the pod that you obtained in Step b.

    4. View the logs associated with the PCE server by using the following command:

      The following is a sample PCE server log entry:

    5. If the PCE server logs indicate a problem with the PCE server, you can manually restart the PCE server pod by using the following command:

    If the logs do not contain the information that you are looking for, you can also run a variety of show commands on the PCE server to obtain the information. Just as with Junos OS syntax, you can enter show ? to see the show command options.

  3. The PCE server performs the following actions after it receives the provisioning order:

    • The PCE server forwards the order to the Path Computation Client (PCC).

    • The PCE server sends an acknowledgment back to the PCS.

  4. The LSP controller status changes to PCC_PENDING, indicating that the PCE server received the provisioning order and forwarded it to the PCC, but the PCC has not yet responded. If an LSP is stuck in the PCC_PENDING state, it suggests that the problem lies with the PCC. Check the configuration on the PCC. For information on how to check the configuration on the PCC, refer to your vendor's documentation for the PCC.

  5. If the PCC receives the provisioning order successfully, it sends a response to the PCE server, which in turn forwards the response to the PCS. When the PCS receives this response, the PCS clears the LSP controller status completely. A clear status indicates that the PCS has provisioned the LSP and that no action is pending from the PCE server or PCC. The operational status for the tunnel then becomes the indicator for the condition of the tunnel. You can view the operational status in the Op Status column on the Tunnel tab of the network information table. The following is a sample log entry that the PCS generates: