Interfaces:
POS2/0 (ldp): xmit/recv
LDP Id: 172.31.255.255:0
Tunnel1 (ldp): Targeted -> 192.168.255.255
Targeted Hellos:
172.16.0.0 -> 192.168.255.255 (ldp): active, xmit/recv
LDP Id: 192.168.255.255:0
172.16.0.0 -> 192.168.0.0 (tdp): passive, xmit/recv
TDP Id: 192.168.0.0:0
This command output indicates that:
• The local LSR (172.16.0.0) sent LDP link Hello messages on interface POS2/0 and discovered
neighbor 172.31.255.255.
• The local LSR sent LDP targeted Hello messages associated with interface Tunnel1 to target
192.168.255.255. The LSR was configured to use LDP.
• The local LSR is active for targeted discovery activity with 192.168.255.255; this means that the
targeted Hello messages it sends to 192.168.255.255 carry a response request. The local LSR was
configured to have an LDP session with the nondirectly connected LSR 192.168.255.255.
• The local LSR is not passive from the discovery activity with 192.168.255.255 for one of the
following reasons:
◦The targeted Hello messages it receives from 192.168.255.255 do not carry a response request.
◦The local LSR has not been configured to respond to such requests.
• The local LSR sent TDP directed Hello messages to the target LSR 192.168.0.0. This LSR uses TDP
because the Hello messages received from the target LSR 192.168.0.0 were TDP directed Hello
messages.
• The local LSR is passive in discovery activity with LSR 192.168.0.0. This means that the directed
Hello messages it receives from LSR 192.168.0.0 carry a response request and that the local LSR has
been configured with the mpls ldp discovery targeted-hello accept command to respond to such
requests from LSR 192.168.0.0.
• The local LSR is not active in discovery activity with LSR 192.168.0.0, because no application that
requires an LDP session with LSR 192.168.0.0 has been configured on the local LSR.
For examples of configuring LDP targeted sessions, see the Establishing Nondirectly Connected MPLS
LDP Sessions Example, page 23.
Saving Configurations MPLS Tag Switching Commands
In releases of Cisco IOS software prior to 12.4(2)T, some MPLS commands had both a tag-switching
version and an MPLS version. For example, the two commands tag-switching ip and mpls ip were the
same. To support backward compatibility, the tag-switching form of the command was written to the saved
configuration.
Starting in Cisco IOS Release 12.4(2)T, the MPLS form of the command is written to the saved
configuration.
For example, if an ATM interface is configured using the following commands, which have both a tag-
switching form and an MPLS form:
Router(config)# interface ATM3/0
Router(config-if)# ip unnumbered Loopback0
router(config-if)# tag-switching ip
Router(config-if)# mpls label protocol ldp
After you enter these commands and save this configuration or display the running configuration with the
show runningcommand, the commands saved or displayed appear as follows:
interface ATM3/0
Saving Configurations MPLS Tag Switching Commands
How to Configure MPLS LDP
MPLS LDP Configuration Guide, Cisco IOS Release 12.4
11