4000 Router Series MPLS Configuration Guide

--- FEC: 11.1.1.0/24 ping statistics ---

5 packets transmitted, 5 packets received, 0.0% packet loss

round-trip min/avg/max = 1/1/1 ms

Label advertisement control configuration example

Network requirements

Two links, Router A—Router B—Router C and Router A—Router D—Router C, exist between subnets

11.1.1. 0 / 24 a n d 21.1.1.0 / 24 .

Configure label advertisement control, so LDP sets up LSPs only on the link Router A—Router B—Router

C to forward traffic between subnets 11.1.1.0 / 24 a n d 21.1.1.0 / 24 .

Figure 18 Network diagram

Configuration considerations

1. Configure a routing protocol on each router to make sure that the routers can reach each other.

This example uses OSPF.

2. Enable LDP on each router.

3. Configure LSP generation policies so LDP uses only the routes 11.1.1.0/24 and 21.1.1.0/24 to

establish LSPs.

4. Configure label advertisement policies, so LDP sets up LSPs only over the link Router A—Router

B—Router C, as follows:

{ Router A advertises only the label mapping for FEC 11.1.1. 0 / 24 t o Ro u t e r B.

{ Router C advertises only the label mapping for FEC 21.1.1.0/24 to Router B.

{ Router D does not advertise label mapping for FEC 21.1.1.0/24 to Router A. Router D does not

advertise label mapping for FEC 11.1.1.0 / 24 t o Ro u t e r C .

Configuration procedure

1. Configure IP addresses and masks for interfaces, including the loopback interfaces, as shown

in Figure 18. (Details not

shown.)

2. Configure OSPF on each router to ensure IP connectivity between them. (Details not shown.)