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via t1-4/0/0.0, Push 100000<br />

192.168.17.1/32 *[LDP/9] 5d 00:51:17, metric 1<br />

> via t1-4/0/0.0<br />

This output shows two LDP FECs (routes) to the two LDP neighbors. The first FEC<br />

is to the LSP’s egress router, 192.168.16.1/32 (RouterF), and the second is to the<br />

transit router. Both FECs have a route preference of 9 and a metric of 1, which are<br />

the default JUNOS values for LDP. Both routes use the t1-4/0/0 interface, which is<br />

what you expect. The end of the second line of the FEC for 192.168.16.1/32 shows a<br />

push operation and a label value. When forwarding packets, LDP pushes a label of<br />

100000 onto the packet. LDP stores all the labels being used in LDP-signaled LSPs,<br />

which you can display with the following command:<br />

aviva@RouterF> show ldp database<br />

Input label database, 192.168.16.1:0--192.168.17.1:0<br />

Label Prefix<br />

100000 192.168.16.1/32<br />

3 192.168.17.1/32<br />

100032 192.168.19.1/32<br />

Output label database, 192.168.16.1:0--192.168.17.1:0<br />

Label Prefix<br />

3 192.168.16.1/32<br />

100000 192.168.17.1/32<br />

100032 192.168.19.1/32<br />

The inet.3 table on RouterF shows similar FECs:<br />

aviva@RouterF> show route table inet.3<br />

inet.3: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden)<br />

+ = Active Route, - = Last Active, * = Both<br />

192.168.17.1/32 *[LDP/9] 5d 03:33:23, metric 1<br />

> to 10.0.8.1 via fe-0/0/1.0<br />

192.168.19.1/32 *[LDP/9] 5d 00:57:15, metric 1<br />

> to 10.0.8.1 via fe-0/0/1.0, Push 100032<br />

When the router is forwarding packets on this LSP, LDP pushes a label value, this<br />

time 100032, onto all packets entering the LSP.<br />

The second JUNOS routing table, mpls.0, stores label values for MPLS and for LDP.<br />

Here’s the mpls.0 table on RouterG:<br />

aviva@RouterG> show route table mpls.0<br />

mpls.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)<br />

+ = Active Route, - = Last Active, * = Both<br />

0 *[MPLS/0] 5d 03:58:02, metric 1<br />

Receive<br />

1 *[MPLS/0] 5d 03:58:02, metric 1<br />

Receive<br />

2 *[MPLS/0] 5d 03:58:02, metric 1<br />

Viewing Information and LDP-Signaled LSPs in the Routing Tables | 495<br />

This is the Title of the Book, eMatter Edition<br />

Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.

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