I can't see MPLS in the routing table

[LincolnR]

I have installed two XRv routers with MPLS and LDP configuration. However, I cannot find MPLS or LDP neighbors and the routing table does not have the MPLS protocol.

RP/0/0/CPU0:AGG-1#ping 10.1.1.2 Success rate is 100 percent (5/5), round-trip min/avg/max = 1/16/69 ms

""""""""""""""""""""""""""""""""

RP/0/0/CPU0:AGG-1#sh mpls ldp neighbor

Thu May 15 18:02:51.705 UTC """""""""""""""""""""""""""""""""""

RP/0/0/CPU0:AGG-1#sh mpls ldp interface

Interface GigabitEthernet0/0/0/1 (0x40) VRF: 'default' (0x60000000) Enabled via config: LDP interface

RP/0/0/CPU0:AGG-1#sh mpls interfaces detail

Thu May 15 18:04:59.506 UTC

Interface GigabitEthernet0/0/0/1: LDP(A) MPLS enabled

RP/0/0/CPU0:AGG-1#sh mpls interfaces

Thu May 15 18:10:40.883

UTC Interface LDP Tunnel Static Enabled -------------------------- -------- -------- -------- -------- GigabitEthernet0/0/0/1 Yes No No Yes

RP/0/0/CPU0:AGG-1# ################# """""""""""""""""""""""""""""""""""""""""""

RP/0/0/CPU0:AGG-2#ping 10.1.1.1 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/4/9 ms

RP/0/0/CPU0:AGG-2#sh mpls ldp neighbor

Thu May 15 18:08:24.402 UTC

RP/0/0/CPU0:AGG-2#sh mpls ldp interface

Thu May 15 18:08:54.440 UTC

Interface GigabitEthernet0/0/0/2 (0x60)

VRF: 'default' (0x60000000)

Enabled via config: LDP interface

RP/0/0/CPU0:AGG-2#sh mpls ldp interface

Thu May 15 18:09:18.748 UTC

RP/0/0/CPU0:AGG-2#sh mpls interfaces

Thu May 15 18:10:12.495 UTC

Interface LDP Tunnel Static Enabled -------------------------- -------- -------- -------- -------- GigabitEthernet0/0/0/2 Yes No No Yes

P/0/0/CPU0:AGG-2#sh running-config
Thu May 15 18:18:38.080 UTC
Building configuration...
!! IOS XR Configuration 6.1.3
!! Last configuration change at Thu May 15 16:09:35 2025 by admin
!
hostname AGG-2
interface Loopback0
ipv4 address 2.2.2.2 255.255.255.255
!
interface MgmtEth0/0/CPU0/0
shutdown
!
interface GigabitEthernet0/0/0/0
shutdown
!
interface GigabitEthernet0/0/0/1
shutdown
!
interface GigabitEthernet0/0/0/2
description TO-AGG-1
ipv4 address 10.1.1.2 255.255.255.252
!
mpls ldp
router-id 2.2.2.2
address-family ipv4
!
interface GigabitEthernet0/0/0/2
!
!
end
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

RP/0/0/CPU0:AGG-1#sh runn
Thu May 15 18:17:46.414 UTC
Building configuration...
!! IOS XR Configuration 6.1.3
!! Last configuration change at Thu May 15 15:56:32 2025 by admin
!
hostname AGG-1
interface Loopback0
ipv4 address 1.1.1.1 255.255.255.255
!
interface MgmtEth0/0/CPU0/0
shutdown
!
interface GigabitEthernet0/0/0/0
shutdown
!
interface GigabitEthernet0/0/0/1
description TO-AGG-2
ipv4 address 10.1.1.1 255.255.255.252
!
interface GigabitEthernet0/0/0/2
shutdown
!
mpls ldp
router-id 1.1.1.1
address-family ipv4
!
interface GigabitEthernet0/0/0/1
!
!
end

RP/0/0/CPU0:AGG-1#

###################

RP/0/0/CPU0:AGG-1#sh route
Sat May 17 00:24:50.066 UTC

Codes: C - connected, S - static, R - RIP, B - BGP, (>) - Diversion path
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - ISIS, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, su - IS-IS summary null, * - candidate default
U - per-user static route, o - ODR, L - local, G - DAGR, l - LISP
A - access/subscriber, a - Application route
M - mobile route, r - RPL, (!) - FRR Backup path

Gateway of last resort is not set

L 1.1.1.1/32 is directly connected, 1d08h, Loopback0
C 10.1.1.0/30 is directly connected, 1d09h, GigabitEthernet0/0/0/1
L 10.1.1.1/32 is directly connected, 1d09h, GigabitEthernet0/0/0/1
RP/0/0/CPU0:AGG-1#

############################

RP/0/0/CPU0:AGG-2#sh route
Sat May 17 00:26:18.610 UTC

Codes: C - connected, S - static, R - RIP, B - BGP, (>) - Diversion path
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - ISIS, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, su - IS-IS summary null, * - candidate default
U - per-user static route, o - ODR, L - local, G - DAGR, l - LISP
A - access/subscriber, a - Application route
M - mobile route, r - RPL, (!) - FRR Backup path

Gateway of last resort is not set

L 2.2.2.2/32 is directly connected, 1d08h, Loopback0
C 10.1.1.0/30 is directly connected, 1d08h, GigabitEthernet0/0/0/2
L 10.1.1.2/32 is directly connected, 1d08h, GigabitEthernet0/0/0/2
RP/0/0/CPU0:AGG-2#

[Harold Ritter]

Hi @LincolnR ,

The issue is that you do not have an IGP configured between the two routers. LDP tries to establish an TCP session between the router-id of the two neighbors, but it doesn't have a route to the neighbor router-id, so it won't come up.

You need to configure ISIS or OSPF and advertise the loopback address. This will cause the LDP neighbor relationship to come up.

[LincolnR]

I configured OSPF and advertised L0. MPLS still does not appear in the routing table.

RP/0/0/CPU0:AGG-1#show mpls ldp interface brief
Fri May 23 15:10:49.826 UTC
Interface VRF Name Config Enabled IGP-Auto-Cfg TE-Mesh-Grp cfg
--------------- ------------------- ------ ------- ------------ ---------------
Gi0/0/0/1 default Y Y 0 N/A
RP/0/0/CPU0:AGG-1#show route ospf
Fri May 23 15:10:57.605 UTC

O 2.2.2.2/32 [110/2] via 10.1.1.2, 01:54:41, GigabitEthernet0/0/0/1
RP/0/0/CPU0:AGG-1#show mpls ldp neighbor
Fri May 23 15:11:34.003 UTC

RP/0/0/CPU0:AGG-1#show running mpls ldp
Fri May 23 15:11:57.121 UTC
mpls ldp
router-id 1.1.1.1
address-family ipv4
discovery targeted-hello accept
neighbor 10.1.1.2 targeted
!
interface GigabitEthernet0/0/0/1
!
!

RP/0/0/CPU0:AGG-1#show running | b ospf
router ospf 1
router-id 192.168.1.1
passive disable
area 0
passive disable
interface Loopback0
passive disable
neighbor 10.1.1.2
!
interface GigabitEthernet0/0/0/1
network point-to-point
!
!
network point-to-point
!
!
!
mpls ldp
router-id 1.1.1.1
address-family ipv4
discovery targeted-hello accept
neighbor 10.1.1.2 targeted
!
interface GigabitEthernet0/0/0/1
#################################################################################

RP/0/0/CPU0:AGG-2#show mpls ldp interface brief
Fri May 23 15:10:26.987 UTC
Interface VRF Name Config Enabled IGP-Auto-Cfg TE-Mesh-Grp cfg
--------------- ------------------- ------ ------- ------------ ---------------
Gi0/0/0/2 default Y Y 0 N/A
RP/0/0/CPU0:AGG-2#show route ospf
Fri May 23 15:11:03.365 UTC

O 1.1.1.1/32 [110/2] via 10.1.1.1, 01:54:46, GigabitEthernet0/0/0/2
RP/0/0/CPU0:AGG-2#show mpls ldp neighbor
Fri May 23 15:11:38.523 UTC

RP/0/0/CPU0:AGG-2#show running mpls ldp
Fri May 23 15:12:04.041 UTC
mpls ldp
router-id 1.1.1.1
address-family ipv4
discovery targeted-hello accept
neighbor 10.1.1.1 targeted
!
interface GigabitEthernet0/0/0/2
!
!

RP/0/0/CPU0:AGG-2#show running | b ospf
router ospf 1
router-id 192.168.1.2
area 0
interface Loopback0
passive disable
neighbor 10.1.1.1
!
interface GigabitEthernet0/0/0/2
network point-to-point
!
!
!
!
mpls ldp
router-id 1.1.1.1
address-family ipv4
discovery targeted-hello accept
neighbor 10.1.1.1 targeted
!
interface GigabitEthernet0/0/0/2
!
!
end

RP/0/0/CPU0:AGG-2#

[Harold Ritter · Accepted solution]

Hi @LincolnR ,

The mpls ldp router-id on AGG-2 is 1.1.1.1 and it should be 2.2.2.2.

Also, your ldp configuration should be as simple as this:

mpls ldp
router-id 1.1.1.1
!
interface GigabitEthernet0/0/0/1

and 

mpls ldp
router-id 2.2.2.2
!
interface GigabitEthernet0/0/0/2

[LincolnR]

Harold

I didn't pay attention to the router-id configuration.
The simple configuration was the main issue.

RP/0/0/CPU0:AGG-1#show mpls ldp neighbor
Fri May 23 17:25:20.273 UTC

Peer LDP Identifier: 2.2.2.2:0
TCP connection: 2.2.2.2:30007 - 1.1.1.1:646
Graceful Restart: No
Session Holdtime: 180 sec
State: Oper; Msgs sent/rcvd: 28/27; Downstream-Unsolicited
Up time: 00:19:05
LDP Discovery Sources:
IPv4: (1)
GigabitEthernet0/0/0/1
IPv6: (0)
Addresses bound to this peer:
IPv4: (2)
2.2.2.2 10.1.1.2
IPv6: (0)

RP/0/0/CPU0:AGG-1#show mpls forwarding
Fri May 23 17:26:21.269 UTC
Local Outgoing Prefix Outgoing Next Hop Bytes
Label Label or ID Interface Switched
------ ----------- ------------------ ------------ --------------- ------------
24000 Pop 2.2.2.2/32 Gi0/0/0/1 10.1.1.2 4510
RP/0/0/CPU0:AGG-1#