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Identifying Unused FRR Backup Tunnels

 

The next step allows the user to identify unused FRR backup tunnels from the network. The wizard will search for FRR backup tunnels that are not protecting an interface or tunnel within the tunnel ID range specified, and allow the user to inspect and remove any or all of those tunnels from the network before going on to the next step.

Figure 1: Option to Prune Unused FRR Backup Tunnels
Option to Prune Unused FRR Backup Tunnels

If the user chooses to prune unused FRR backup tunnels and enters an appropriate FRR backup tunnel ID range to search, the wizard will return a list of FRR tunnels that are not currently being used to protect any existing LSP tunnels, along with one possible reason. From IP/MPLSView tool’s generated LSP configuration statements, it is possible to derive the element that a tunnel is intended to backup, and therefore to reverse engineer to determine a possible cause of an unused tunnel. For example, the exclude statement, which can be used by a backup tunnel to avoid the element being protected, may be used to determine the element being protected. Note, however, that for FRR backup tunnels configured differently, e.g., with explicit path, information about the node or link being protected by an unused tunnel may not be possible to derive from the configuration statements. In those cases the reason will be shown as “Unknown”. Following is a explanation of reasons that can be indicated under the Possible Reason column:

  • Tunnel not bound to protected interface (inf_name): A backup tunnel was configured, and the intended node or link to be protected was identified by the “exclude” path name. Either the protected link exists but the backup tunnel is not bound to the local interface, or a link exists between the source node and the protected node, but the backup tunnel is not bound to the local interface.

  • Protected interface (inf_name) down: A backup tunnel was configured, and the intended node or link to be protected was identified by the “exclude” path name. Either the protected link exists but the local interface is shutdown, or a link exists between the source node and the protected node, but the local interface is shutdown.

  • Excluded interface (inf_name) down: A backup tunnel was configured, and the intended node or link to be protected was identified by the “exclude” path name. Either the protected link exists but the remote interface is shutdown, or a link exists between the source node and the protected node, but the remote interface is shutdown.

  • Protected interface missing on source node (node_name):A backup tunnel was configured, and the intended node or link to be protected was identified by the “exclude” path name. The protected link does not exist due to missing interface at the source node.

  • Excluded interface missing on remote node (node_name): A backup tunnel was configured, and the intended node or link to be protected was identified by the “exclude” path name. The protected link does not exist due to missing interface at the remote node.

  • Interface missing on either source node or protected node: For node protection tunnel, there was no interface on <snode_name> that shared the same subnet with any interface on the protected node <pnode_name>. This is likely caused by removal of interface on either node.

You can then select from the list the FRR tunnels to delete. Details for a specific FRR tunnel can be viewed by selecting the tunnel and clicking the Details button. A report of all the unused FRR tunnels can be saved to the server by clicking the Report button. To view a saved report, browse to the report file in the File Manager window, right click on the report file, and select Open in Report Viewer.

Figure 2: Select Unused FRR Backup Tunnels for Deletion
Select Unused FRR Backup Tunnels for Deletion

Note that this deletion of FRR tunnels from the network model is permanent. To avoid deleting any tunnels, simply leave all tunnels unchecked (or select Unmark All to uncheck them) and click Next.