Discussion

3 192.168.16.1/32
100000 192.168.17.1/32
100032 192.168.19.1/32
The Input label database section shows the labels received from the LDP peers, and
the Output label database section shows the labels that this router has advertised.
Here, RouterF has advertised a label value of 3 to RouterJ. This reserved label indicates
that RouterF has signaled RouterJ to perform penultimate-hop popping to
remove the top label on the stack before forwarding packets to RouterF.
To verify correct forwarding along the LSP, ping the egress router from the ingress
router. For this to work, you need to configure a loopback address of 127.0.0.1 on
the egress router:
[edit]
aviva@RouterF# set interfaces lo0 unit 0 family inet address 127.0.0.1/32
The egress router uses this address to send echo replies to echo requests sent by the ping
command. Then send an MPLS ping request from the ingress router along the LSP:
aviva@RouterG> ping mpls ldp 192.168.16.1
!!!!!
--- lsping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
The ping echo replies include the label that the ingress router added to the packet
when putting it into the LSP. The ping mpls command uses port 3503 for MPLS echo
requests instead of the UDP port 7, which is used by the standard ping command.
This recipe shows only the commands you need to set up MPLS and LDP. Because
LDP depends on the routing information provided by an IGP, the routers must be
running either IS-IS or OSPF and IPv4 addresses must be configured on all interfaces
running LDP and the IGP. For the ingress router in this recipe, here are the parts of
the configuration related to setting up the LDP-signaled LSP:
aviva@RouterG> show configuration interfaces
t1-4/0/0 {
unit 0 {
family inet {
address 10.0.0.1/24;
}
family mpls;
}
}
lo0 {
unit 0 {
family inet {
address 192.168.19.1/32;
}
}
}
aviva@RouterG> show configuration routing-options
router-id 192.168.19.1;
492 | Chapter 14: MPLS
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