BGP RIB-failure ::/0

[sebastien3]

Hello,

I have 3 routers that use BGP (Internal/External) + EIGRP for IGP.

Here is the quick configuration of routers :

-- R1 (fd12:3456:789a:1::1)

ipv6 route ::/0 Null0

router bgp 100
address-family ipv6
network ::/0

R1#sh ipv6 route ::/0
Routing entry for ::/0
Known via "static", distance 1, metric 0
Backup from "eigrp 10 [170]"
Route count is 1/1, share count 0
Routing paths:
directly connected via Null0
Last updated 1w0d ago

-- R2 (fd12:3456:789a:1::2)

ipv6 route ::/0 Null0

router bgp 100
address-family ipv6
network ::/0

R2#sh ipv6 route ::/0
Routing entry for ::/0
Known via "static", distance 1, metric 0
Backup from "eigrp 10 [170]"
Route count is 1/1, share count 0
Routing paths:
directly connected via Null0
Last updated 1w0d ago

-- R3 (fd12:3456:789a:1::3)

ipv6 route ::/0 Null0

router bgp 100
address-family ipv6
network ::/0

R3#sh ipv6 route ::/0
Routing entry for ::/0
Known via "static", distance 1, metric 0
Backup from "bgp 100 [200]"
Route count is 1/1, share count 0
Routing paths:
directly connected via Null0
Last updated 2d01h ago

R3#sh bgp ipv6 uni rib-failure
Network Next Hop RIB-failure RIB-NH Matches
::/0 fd12:3456:789a:1::1
IPv6 Higher admin distanc n/a

Only one router the R3 has a rib-failure. The difference compared to R1 and R2 is that it knows ::/0 by BGP instead of EIGRP like the others.
I don't understand why because the configuration of the 3 routers is identical

An idea ?

[MHM Cisco World]

the backup is from iBGP, the BGP if find the same prefix learn from better IGP path it not inject to RIB.

[Martin L]

Good thing about this type of failure is that it tells you why

Higher admin distanc  in show ip bgp

is this why ?  Backup from "bgp 100 [200]" vs. Backup from "eigrp 10 [170]"

[sebastien3]

Yes but why is it only R3 which has this behavior ?

R3 does not receive ::/0 from eBGP...

sh bgp ipv6 uni neighbors XXXX:X:X:X::X:1 received-routes | inc ::/0

[MHM Cisco World]

can I see

show ip bgp

for three routers ?

[sebastien3]

R1#sh bgp ipv6 uni
BGP table version is 451614532, local router ID is 10.0.0.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path
* i ::/0 fd12:3456:789a:1::2
12800 100 0 i
*> :: 0 32768 i

R2#sh bgp ipv6 uni
BGP table version is 236579704, local router ID is 10.0.0.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path
* i ::/0 fd12:3456:789a:1::1
0 100 0 i
* :: 0 32768 i
*> FE80::CE16:7EFF:FEAA:5B94
12800 32768 i

R3#sh bgp ipv6 uni
BGP table version is 7109274, local router ID is 10.0.0.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path
r>i ::/0 fd12:3456:789a:1::1
0 100 0 i
r i fd12:3456:789a:1::2
12800 100 0 i

[MHM Cisco World]

I think there is suboptimal loop here but I need to more check the Case.

[sebastien3]

OK if need something please tell me.

[MHM Cisco World]

NO It easy three routers each config with default route toward Null0 and there is EIGRP connect the three routers, 
I will check if there is multi redistribution in some point and see it effect if it same as your or not. 

[MHM Cisco World]

Only one thing I need 

Clear ip bgp 100 

and then check again.

[Harold Ritter]

Hi @sebastien3 ,

it looks like R3 is the only router that does not originate the default route via BGP.

R3#sh bgp ipv6 uni

...
Network Next Hop Metric LocPrf Weight Path
r>i ::/0 fd12:3456:789a:1::1 0 100 0 i

This explains why you see the RIB failure on R3.

Can you provide the

show bgp ipv6 uni ::/0

output from R3.

Regards,

[sebastien3]

@MHM Cisco WorldOK !

@Harold Ritter:

R3#show bgp ipv6 uni ::/0
BGP routing table entry for ::/0, version 4776991
Paths: (2 available, best #1, table default, RIB-failure(145))
Not advertised to any peer
Refresh Epoch 2
Local, (received & used)
fd12:3456:789a:1::1 from fd12:3456:789a:1::1 (10.0.0.1)
Origin IGP, metric 0, localpref 100, valid, internal, best
rx pathid: 0, tx pathid: 0x0
Refresh Epoch 2
Local, (received & used)
fd12:3456:789a:1::2 from fd12:3456:789a:1::2 (10.0.0.2)
Origin IGP, metric 12800, localpref 100, valid, internal
rx pathid: 0, tx pathid: 0

[Harold Ritter]

Hi @sebastien3 ,

That confirms that R3 does not originate the default route, despite the original configuration you posted. This is definitely why you are seeing the RIB failure only on R3. Make sure the network statement (network ::/0) is configured on R3.

Regards,

[sebastien3]

@MHM Cisco World:

clear bgp ipv6 unicast 

on R3 does not change anything I still have RIB-Failure

@Harold Ritter: I have network::/0 in the BGP configuration...

[Harold Ritter]

@sebastien3 ,

It is not normal that you have a network statement for ::/0 and a static route to null0 for the same prefix and yet R3 is not originating the ::/0. Could you please provide the

show runn | sec router bgp

output from R3?

You might want to try removing the network statement and re-apply it.

Regards,