426 Appendix B Service Provider Tag Switching with OSPF and IS-IS

Gateway of last resort is not set

192.168.1.0 255.255.255.255 is subnetted, 1 subnets B 192.168.1.1 [20/0] via 192.168.3.9, 00:11:45

192.168.2.0 255.255.255.255 is subnetted, 1 subnets

C192.168.2.1 is directly connected, Loopback0 192.168.3.0 255.255.255.252 is subnetted, 2 subnets

C192.168.3.8 is directly connected, Serial0

B 192.168.3.4 [20/0] via 192.168.3.9, 00:11:45

Tags

In this section, the mapping of tags to IP prefixes shows that a complete

LSP exists between the loopback addresses on the Atlanta and Raleigh POP routers. With an end-to-end LSP, the Core router only needs to examine the label, and therefore does not require full knowledge of the peer subnets.

Atlanta POP Forwarding Table

In the following output from the Atlanta POP router, you can see that a full LSP exists between the Atlanta and Raleigh POP routers:

Core Forwarding Table

On the Core router, labeled packets between the Atlanta and Raleigh POP routers will be label-switched, as indicated in the forwarding table: