03-13-2023 05:23 PM
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
Solved! Go to Solution.
03-15-2023 03:12 AM
Details below. I have other LDP vlans in the same router switch but just this vlan is not working.
As you can see below, LDP can see both sides but if i issue sh mpls ldp neighbour i dont get any output.
Switch#sh mpls ldp discovery detail
Local LDP Identifier:
192.168.240.42:0
Discovery Sources:
Interfaces:
Vlan923 (ldp): xmit/recv
Enabled: Interface config
Hello interval: 5000 ms; Transport IP addr: 192.168.240.42
LDP Id: 192.168.249.2:0
Src IP addr: 192.168.240.45; Transport IP addr: 192.168.249.2
Hold time: 15 sec; Proposed local/peer: 15/15 sec
Reachable via 192.168.249.2/32
Password: not required, none, in use
Clients: IPv4, mLDP
==========================
Router#sh mpls ldp discovery detail
Local LDP Identifier:
192.168.249.2:0
Discovery Sources:
Interfaces:
GigabitEthernet0/0/3.923 (ldp): xmit/recv
Enabled: Interface config
Hello interval: 5000 ms; Transport IP addr: 192.168.249.2
LDP Id: 192.168.240.42:0
Src IP addr: 192.168.240.46; Transport IP addr: 192.168.240.42
Hold time: 15 sec; Proposed local/peer: 15/15 sec
Reachable via 192.168.240.40/30
Password: not required, none, in use
Clients: IPv4, mLDP
03-15-2023 03:24 AM
192.168.240.40/30 <<- this not OK, I dont now sure why but the LDP only accept neighbor with /31 & /32 router-ID, not /30
so you have two solution as I mention before,
config transport
config LO use it as router-ID
192.168.249.2/32 <<- this OK, you can use it as Router-ID
03-15-2023 03:50 AM - edited 03-16-2023 01:41 AM
Hi, Thank you.
I think you are right.. I will force the LDP in Switch to use /32 loopback. I think its taken the VLAN IP of /30 instead of /32 loopback.
I will do this next week and update.
03-17-2023 03:26 PM - edited 03-17-2023 03:27 PM
MPLS – Transport-Address vs LDP Router-ID (RID), how they are tied together, and how to configure them to differ, and how that can help “engineer” the network! – The DEVNET GRIND! (loopedback.com)
more about the router-id and transport-address
thanks
MHM
03-21-2023 09:52 AM
Hi,
So I forced the LDP id to /32 loopback address and the LDP neighbour came up.
Thank you for your help.
03-21-2023 09:54 AM
You are so welcome
and thanks you update us.
have a nice day
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