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Example: Node-Link Protection Configuration

Figure 1: Node-Link Protection Topology DiagramNode-Link Protection Topology Diagram

Figure 1 shows an example of how you can implement node-link protection. An LSP is initiated on Router 0 with a strict path travelling through Router 1, Router 2, Router 3, and Router 4. You configure node-link protection within the LSP and link protection on all RSVP interfaces in the path.

On Router 0, configure an LSP to travel across routers 1, 2, 3, and 4. Include the node-link-protection statement in the LSP and configure link protection on outgoing RSVP interface fe-0/1/1. To support the LSP, configure OSPF, MPLS, and RSVP on the needed interfaces.

Router 0

On Router 1, configure link protection on outgoing RSVP interface so-0/0/3. Configure OSPF, MPLS, and RSVP on all transit interfaces.

Router 1

On Router 2, configure link protection on outgoing RSVP interface so-0/0/0. Configure OSPF, MPLS, and RSVP on all transit interfaces.

Router 2

On Router 3, configure link protection on outgoing RSVP interface fe-0/1/2. Configure OSPF, MPLS, and RSVP on all transit interfaces.

Router 3

Because Router 4 is the endpoint of the LSP, you can configure interfaces and protocols as usual. There is no need to configure any node-link protection or link protection statements on this router.

Router 4

Verifying Your Work

To verify proper operation of MPLS LSP node-link protection, use the following commands:

  • show mpls lsp extensive

  • show route detail

  • show rsvp neighbor detail

  • show rsvp session detail

The following section shows the output of these commands used with the configuration example.

The show mpls lsp extensive command provides some useful information about link protection and node-link protection. The protection flag entry indicates a series of values. By adding the values together, you can learn the protection state of an LSP based on the total sum. Significant values for the flags include: 1 = Available (Link Protection), 2 = In Use, and 8 = Node Protection. Thus, a value of 9 means that node protection is available (1 + 8 = 9) and a value of A means that a node protected link is in use (8 + 2 = A, in hexadecimal).