no host route: What does this mean in the context of LDP?

[mark.freese@radianz.com]

Cisco community:

This is a directly connected interface and I have a routing protocol running. Why does mpls ldp discovery tell me I have no host route?

P1#show mpls ldp discovery 
Local LDP Identifier:
10.10.1.5:0
Discovery Sources:
Interfaces:
GigabitEthernet0/0 (ldp): xmit/recv
LDP Id: 2.2.2.2:0
GigabitEthernet0/1 (ldp): xmit/recv
LDP Id: 172.31.1.2:0; no host route

P1#ping 172.31.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.31.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
P1#show ip route 172.31.1.2
Routing entry for 172.31.1.0/30
Known via "connected", distance 0, metric 0 (connected, via interface)
Redistributing via ospf 1
Routing Descriptor Blocks:
* directly connected, via GigabitEthernet0/1
Route metric is 0, traffic share count is 1
P1#
P1#

[Georg Pauwen · Accepted solution]

Hello,

--> Routing entry for 172.31.1.0/30

This is the reason. A host route should be a /32 route. If you change the interface with IP address 172.31.1.2 to a /32, the 'no host route' will disappear. Typically, loopback interfaces with /32 masks are used for MPLS LDP router ID's...

[mark.freese@radianz.com]

Georg:

I actually had a /32 loopback configured and "mpls ldp router-id Loopback10" command but the router still preferred the physical interface. I guess I enabled ldp before I created the loopback. 

I had to amend the router-id command with the "force" option.

Many thanks for the answer.

[Georg Pauwen]

Hello,

'mpls ldp router-id lo10 force'

is indeed recommended. That way, the loopback is forced to be the ID.