ldp neighbour not coming up

[Psmurali89]

Hi All 

Am tying to establish LDP neighbour between 2 devices but its not coming up.. Both sides saying they are sending and receiving but neighbour is not coming up.  In-between these 2 devices there are one Layer2 switch (Cisco 9200 Version 17.3.6) managed by us and a Layer3 ISP device. I can ping between those vlan's, BGP (i used BGP between these 2 VLAN's) and OSPF is up but just LDP is not coming up. 

Not sure if the issues is with those devices? Any help/suggestions is much appreciated. 

Router1: 

GigabitEthernet0/0/3.923 (ldp): xmit/recv
LDP Id: 192.168.240.42:0

Switch1: 

Vlan923 (ldp): xmit/recv
LDP Id: 192.168.249.2:0

SWITCH1#sh mpls ldp neighbour

ROUTER1#sh mpls ldp neighbour

[MHM Cisco World]

show mpls ldp discovery
check if the local ID is same as it appear in neighbor. 

[Psmurali89]

i think this is where the issue is.. how to set the ldp ID manually? 

[MHM Cisco World]

mpls ldp router-id loopback0 force <<- forece make LDP use new router-id.

[Psmurali89]

I have got multiple ldp instance. How to set individual id for each ldp vlan/loop back? 

[MHM Cisco World]

All ldp instance will use same ldp id,

What important is make this id reachable by all ldp neighbors. 

[Psmurali89]

yes as I mentioned in first post, I can reach 192.168.240.42 (switch1 ip) from router1 and vice versa. So the ldp id is reachable both sides and sh mpls discovery shows both sides can transmit and receive but still the neighbour Is not coming up. 

[MHM Cisco World]

show mpls ldp discovery

Share this for both peet let me check

[Psmurali89]

below is the output from both device. I can ping those ldp ID address. 

Router1: 

GigabitEthernet0/0/3.923 (ldp): xmit/recv
LDP Id: 192.168.240.42:0

Switch1: 

Vlan923 (ldp): xmit/recv
LDP Id: 192.168.249.2:0

[filopeter]

Make sure that your devices are reachable (see aeach other) using OSPF, not by BGP.  As it seems they are not directly connected, you need to configure targeted LDP session. In case of targeted LDP, please do not forget to configure "mpls ldp discovery targeted-hello accept"  on both devices.

[Harold Ritter]

Hi @Psmurali89 ,

Can you provide a "show run int" for both GigabitEthernet0/0/3.923 and Vlan923.

Regards,

[Psmurali89]

sh run int vlan923
Building configuration...

Current configuration : 172 bytes
!
interface Vlan923
mtu 1524
ip address 192.168.240.46 255.255.255.252
ip ospf 10 area 0
mpls ip
mpls label protocol ldp
end

!

sh run int gi0/0/3.923
Building configuration...

Current configuration : 205 bytes
!
interface GigabitEthernet0/0/3.923
encapsulation dot1Q 923
ip address 192.168.240.45 255.255.255.252
ip ospf 10 area 0
mpls ip
mpls label protocol ldp
end

The OSPF process is UP, I can ping between 2 devices on VLAN 923 and loopback. 

Switch#sh mpls ldp discovery

Interfaces:
Vlan922 (ldp): xmit
Vlan923 (ldp): xmit/recv
LDP Id: 192.168.249.2:0  <<<<<<<<<< Loopback IP of below router 

Router#sh mpls ldp discovery

GigabitEthernet0/0/3.923 (ldp): xmit/recv
LDP Id: 192.168.240.42:0   <<<<<<<<<<< it took the ID of another LDP VLAN i have in the above switch. But all IP's in the LDP between 2 devices is reachable and also the OSPF is UP. 

[MHM Cisco World]

mpls ldp discovery transport-address interface <- I already check and find command can help you to override router id 
use this command and check again 

[Psmurali89]

Hi,

sorry didn't get it? does ldp id matter here? a router or switch can have multiple ldp vlans but there will be only one ldp I'd and as long as that ldp I'd is reachable then it should work? 

[MHM Cisco World]

Router#sh mpls ldp discovery detail <<- share this please