IOS XRv - BGP does not appear in routing table

[LincolnR]

BGP does not have a neighbor with the peer. It is not in the routing table.

I think it may be something with the image.

RP/0/0/CPU0:ISP#sh runn
Fri May 2 13:04:06.978 UTC
Building configuration...
!! IOS XR Configuration

RP/0/0/CPU0:SP#sh route
Fri May 2 13:17:25.197 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

C 100.10.1.0/30 is directly connected, 00:25:45, GigabitEthernet0/0/0/1
L 100.10.1.2/32 is directly connected, 00:25:45, GigabitEthernet0/0/0/1

6.1.3
!! LasRP/0/0/CPU0:ISP#show bgp trace error
Fri May 2 13:06:47.727 UTC
RP/0/0/CPU0:ISP#t configuration change at Thu May 1 20:23:38 2025 by admin
!
hostname ISP
logging events buffer-size 1024
interface MgmtEth0/0/CPU0/0
shutdown
!
interface GigabitEthernet0/0/0/0
shutdown
!
interface GigabitEthernet0/0/0/1
ipv4 address 100.10.1.1 255.255.255.252
!
interface GigabitEthernet0/0/0/2
shutdown
!
route-policy rp-bgp-allow-all
pass
end-policy
!
router bgp 1
bgp router-id 100.10.1.1
address-family ipv4 unicast
!
neighbor 100.10.1.2
remote-as 2
update-source GigabitEthernet0/0/0/1
address-family ipv4 unicast
route-policy rp-bgp-allow-all in
route-policy rp-bgp-allow-all out
soft-reconfiguration inbound
!

RP/0/0/CPU0:ISP#show bgp summary
Fri May 2 13:05:32.932 UTC
BGP router identifier 100.10.1.1, local AS number 1
BGP generic scan interval 60 secs
Non-stop routing is enabled
BGP table state: Active
Table ID: 0xe0000000 RD version: 4
BGP main routing table version 4
BGP NSR Initial initsync version 3 (Reached)
BGP NSR/ISSU Sync-Group versions 0/0
BGP scan interval 60 secs

BGP is operating in STANDALONE mode.

Process RcvTblVer bRIB/RIB LabelVer ImportVer SendTblVer StandbyVer
Speaker 4 4 4 4 4 0

Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down St/PfxRcd
100.10.1.2 0 2 16 16 4 0 0 00:13:44 0

RP/0/0/CPU0:ISP#show bgp trace error
Fri May 2 13:06:47.727 UTC

RP/0/0/CPU0:ISP#sh route
Fri May 2 13:08:43.079 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

C 100.10.1.0/30 is directly connected, 00:20:07, GigabitEthernet0/0/0/1
L 100.10.1.1/32 is directly connected, 00:20:07, GigabitEthernet0/0/0/1
RP/0/0/CPU0:ISP#

RP/0/0/CPU0:ISP#ping 100.10.1.2
Fri May 2 13:10:12.863 UTC
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.10.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/5/9 ms

==============================================================================

RP/0/0/CPU0:SP#sh runn
Fri May 2 13:11:28.331 UTC
Building configuration...
!! IOS XR Configuration 6.1.3
!! Last configuration change at Thu May 1 20:23:05 2025 by admin
!
hostname SP
interface MgmtEth0/0/CPU0/0
shutdown
!
interface GigabitEthernet0/0/0/0
shutdown
!
interface GigabitEthernet0/0/0/1
ipv4 address 100.10.1.2 255.255.255.252
!
interface GigabitEthernet0/0/0/2
shutdown
!
route-policy rp-bgp-allow-all
pass
end-policy
!
router bgp 2
bgp router-id 100.10.1.2
address-family ipv4 unicast
!
neighbor 100.10.1.1
remote-as 1
update-source GigabitEthernet0/0/0/1
address-family ipv4 unicast
route-policy rp-bgp-allow-all in
route-policy rp-bgp-allow-all out
soft-reconfiguration inbound
!
end

RP/0/0/CPU0:SP#show bgp summary
Fri May 2 13:12:41.206 UTC
BGP router identifier 100.10.1.2, local AS number 2
BGP generic scan interval 60 secs
Non-stop routing is enabled
BGP table state: Active
Table ID: 0xe0000000 RD version: 4
BGP main routing table version 4
BGP NSR Initial initsync version 3 (Reached)
BGP NSR/ISSU Sync-Group versions 0/0
BGP scan interval 60 secs

BGP is operating in STANDALONE mode.

Process RcvTblVer bRIB/RIB LabelVer ImportVer SendTblVer StandbyVer
Speaker 4 4 4 4 4 0

Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down St/PfxRcd
100.10.1.1 0 1 23 23 4 0 0 00:20:52 0

RP/0/0/CPU0:SP#show bgp trace error
Fri May 2 13:16:43.330 UTC
RP/0/0/CPU0:SP#

RP/0/0/CPU0:SP#sh route
Fri May 2 13:17:25.197 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

C 100.10.1.0/30 is directly connected, 00:25:45, GigabitEthernet0/0/0/1
L 100.10.1.2/32 is directly connected, 00:25:45, GigabitEthernet0/0/0/1

RP/0/0/CPU0:SP#ping 100.10.1.1
Fri May 2 13:19:03.220 UTC
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.10.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/4/9 ms

[hawksg2024]

Best of luck with this.

[Ramblin Tech]

To send a prefix to a BGP neighbor, the prefix must first be in the BGP RIB. To be in the BGP RIB, the prefix must be either learned from a BGP neighbor, or injected locally. To inject locally, the prefix must first be in the routing table, then it can be injected with a "network" statement in the BGP config, or redistributed from another routing protocol that has it in its own RIB.

Try this: configure a loopback interface on each node to create a prefix in the local routing table. Then, add a BGP "network" statement to each node for the locally configured loopback address. You should then see each remote loopback address show up as a BGP-learned prefix locally.

[Harold Ritter]

Hi @LincolnR ,

According to the output for the "show bgp summary" you provided, the session is up. The reason that you are not seeing any updates being exchanged is that you are not advertising any prefixes from either neighbor.

Try configuring a loopback interface on both neighbours and advertising it to the other peer as follow:

ISP:

interface lo0

ip address 192.168.100.1/32

router bgp 1

address-family ipv4 unicast

network 192.168.100.1/32

SP:

interface lo0

ip address 192.168.100.2/32

router bgp 2

address-family ipv4 unicast

network 192.168.100.2/32

You should then start seeing updates flowing in both directions.

[LincolnR]

OK. The loopback interfaces are being advertised in the bgp routing table.
However, the command sh bgp neighbor 100.10.1.1 received routes or sh bgp neighbor 192.168.100.1 received routes does not show the routes received by the bgp neighbor.

Output
sh bgp neighbor 100.10.1.1 received

RP/0/0/CPU0:SP#sh bgp neighbor 100.10.1.1 received routes
Fri May 2 14:41:21.352 UTC
% The 'show bgp neighbor received routes' command is only available when inbound soft reconfiguration is active. To activate inbound soft reconfiguration, use the 'soft-reconfiguration inbound' command. If the neighbor supports route-refresh, the 'always' option to the command must also be specified.

Output
sh bgp neighbor 192.168.100.1 received routes
RP/0/0/CPU0:SP#sh bgp neighbor 192.168.100.1 received routes
Fri May 2 14:41:43.780 UTC
% Neighbor not found

[MHM Cisco World]

It easy 

Show .... receive route <<- dont show any prefix dont meaning that bgp not advertise prefix but if peer support route refresh (and soft in not used) then router dont have copy in memory and this command not show anything.

What meaning of missing route' mostly there is filter IN drop prefix.

MHM

[MHM Cisco World]

Debug bgp update <<- use this to see if prefix is exchange or not

MHM

[Harold Ritter]

Hi @LincolnR ,

As the output indicates, "show bgp neighbor received" is only useful is "soft reconfiguration inbound" is configured.

Use this command instead:

sh bgp neighbor 100.10.1.1 routes

[LincolnR]

"Soft reconfiguration inbound" is configured on both.

RP/0/0/CPU0:SP#sh bgp neighbor 100.10.1.1 routes
Fri May 2 15:05:37.292 UTC
BGP router identifier 100.10.1.2, local AS number 2
BGP generic scan interval 60 secs
Non-stop routing is enabled
BGP table state: Active
Table ID: 0xe0000000 RD version: 10
BGP main routing table version 10
BGP NSR Initial initsync version 3 (Reached)
BGP NSR/ISSU Sync-Group versions 0/0
BGP scan interval 60 secs

Status codes: s suppressed, d damped, h history, * valid, > best
i - internal, r RIB-failure, S stale, N Nexthop-discard
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 192.168.100.1/32 100.10.1.1 0 0 1 i

Processed 1 prefixes, 1 paths
******************************************************************************
hostname ISP
logging events buffer-size 1024
interface MgmtEth0/0/CPU0/0
shutdown
!
interface GigabitEthernet0/0/0/0
shutdown
!
interface GigabitEthernet0/0/0/1
ipv4 address 100.10.1.1 255.255.255.252
!
interface GigabitEthernet0/0/0/2
shutdown
!
route-policy rp-bgp-allow-all
pass
end-policy
!
router bgp 1
bgp router-id 100.10.1.1
address-family ipv4 unicast
!
neighbor 100.10.1.2
remote-as 2
update-source GigabitEthernet0/0/0/1
address-family ipv4 unicast
route-policy rp-bgp-allow-all in
route-policy rp-bgp-allow-all out
soft-reconfiguration inbound

*************************

hostname SP
interface MgmtEth0/0/CPU0/0
shutdown
!
interface GigabitEthernet0/0/0/0
shutdown
!
interface GigabitEthernet0/0/0/1
ipv4 address 100.10.1.2 255.255.255.252
!
interface GigabitEthernet0/0/0/2
shutdown
!
route-policy rp-bgp-allow-all
pass
end-policy
!
router bgp 2
bgp router-id 100.10.1.2
address-family ipv4 unicast
!
neighbor 100.10.1.1
remote-as 1
update-source GigabitEthernet0/0/0/1
address-family ipv4 unicast
route-policy rp-bgp-allow-all in
route-policy rp-bgp-allow-all out
soft-reconfiguration inbound

[MHM Cisco World]

Run debug update share result 

MHM

[LincolnR]

RP/0/0/CPU0:ISP#debug bgp update
Fri May 2 15:17:01.392 UTC
RP/0/0/CPU0:ISP#

RP/0/0/CPU0:SP#debug bgp update
Fri May 2 15:18:28.309 UTC
RP/0/0/CPU0:SP#

No result

[MHM Cisco World]

can you hard reset the bgp via 

clear ip bgp 

MHM

[LincolnR]

The command clear bgp * but no result

[MHM Cisco World]

RP/0/0/CPU0:XR#debug bgp policy-execution events <<- share this 

MHM

[Harold Ritter]

Hi @MHM Cisco World ,

Please read the entire thread before making suggestions. Not doing so adds a lot of confusion.