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BGP rib failure:Best steps to eliminate it

news2010a
Participant
Participant

Hi, can you clarify best steps to find the source and eliminate this RIB failure in red below. Full show run from both r1 and r5 routers are attached.
First step is that I go to the next hop (150.4.5.5) indicated at the rib failure. Then I compared BGP and EIGRP statements there. Is the reason for the rib failure because I have 155.4.0.0 and 155.4.0.0/24 advertised under eigrp and bgp?

Rack4R1#show ip bgp
BGP table version is 92, local router ID is 150.4.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*>i28.119.16.0/24   54.4.1.254               0    100      0 54 i
* i                 204.12.4.254             0    100      0 54 i
*>i28.119.17.0/24   54.4.1.254               0    100      0 54 i
* i                 204.12.4.254             0    100      0 54 i
*>i54.4.1.0/24      150.4.6.6                0    100      0 i
*>i112.0.0.0        54.4.1.254               0    100      0 54 50 60 i
* i                 204.12.4.254             0    100      0 54 50 60 i
*>i113.0.0.0        54.4.1.254               0    100      0 54 50 60 i
* i                 204.12.4.254             0    100      0 54 50 60 i
*>i114.0.0.0        54.4.1.254               0    100      0 54 i
* i                 204.12.4.254             0    100      0 54 i
*>i115.0.0.0        54.4.1.254               0    100      0 54 i
* i                 204.12.4.254             0    100      0 54 i
*>i116.0.0.0        54.4.1.254               0    100      0 54 i
* i                 204.12.4.254             0    100      0 54 i
*>i117.0.0.0        54.4.1.254               0    100      0 54 i
* i                 204.12.4.254             0    100      0 54 i
   Network          Next Hop            Metric LocPrf Weight Path
*>i118.0.0.0        54.4.1.254               0    100      0 54 i
* i                 204.12.4.254             0    100      0 54 i
*>i119.0.0.0        54.4.1.254               0    100      0 54 i
* i                 204.12.4.254             0    100      0 54 i
*>i150.4.0.0        150.4.6.6                0    100      0 i
* i                 150.4.4.4                0    100      0 ?
r>i155.4.0.0/24     150.4.5.5                0    100      0 i
*>i155.4.0.0        150.4.6.6          2172416    100      0 i
* i                 150.4.4.4                0    100      0 ?
*>i204.12.4.0       150.4.4.4                0    100      0 i
Rack4R1#show run | s eigrp
router eigrp 100
network 150.4.1.1 0.0.0.0
network 155.4.0.0 0.0.0.255
network 155.4.146.0 0.0.0.255
no auto-summary
Rack4R1#show run | s bgp
router bgp 100
no synchronization
bgp log-neighbor-changes
neighbor IBGP_PEERS peer-group
neighbor IBGP_PEERS remote-as 100
neighbor IBGP_PEERS update-source Loopback0
neighbor IBGP_PEERS route-reflector-client
neighbor 150.4.3.3 peer-group IBGP_PEERS
neighbor 150.4.4.4 peer-group IBGP_PEERS
neighbor 150.4.5.5 peer-group IBGP_PEERS
neighbor 150.4.6.6 peer-group IBGP_PEERS
no auto-summary
Rack4R1#
RSRack4AS>5
[Resuming connection 5 to R5 ... ]

Rack4R5#show run | s eigrp
no ip split-horizon eigrp 100
router eigrp 100
network 150.4.5.0 0.0.0.255
network 155.4.0.0
no auto-summary
Rack4R5#show run | s bgp
router bgp 100
no synchronization
bgp log-neighbor-changes
network 155.4.0.0 mask 255.255.255.0
neighbor 150.4.1.1 remote-as 100
neighbor 150.4.1.1 update-source Loopback0
no auto-summary
Rack4R5#

1 ACCEPTED SOLUTION

Accepted Solutions

Jon Marshall
VIP Community Legend VIP Community Legend
VIP Community Legend

news2010a wrote:

Hi, can you clarify best steps to find the source and eliminate this RIB failure in red below. Full show run from both r1 and r5 routers are attached.
First step is that I go to the next hop (150.4.5.5) indicated at the rib failure. Then I compared BGP and EIGRP statements there. Is the reason for the rib failure because I have 155.4.0.0 and 155.4.0.0/24 advertised under eigrp and bgp?

Rack4R5#

Marlon

Basically yes, because IBGP AD is 200 and EIGRP AD is 90 (Internal) and 170 (External). So the BGP route cannot be inserted into the routing table because the EIGRP route is preferred and in the route table.

If you run "sh ip bgp rib-failure" on the router it should give you an idea why it was not installed in the routing table.

Edit - note that just because it failed to install in the routing table, this will not stop the BGP process from advertising this route to other BGP peers. If you don't want this happening use the "bgp suppress-inactive" command.

Jon

View solution in original post

11 REPLIES 11

Jon Marshall
VIP Community Legend VIP Community Legend
VIP Community Legend

news2010a wrote:

Hi, can you clarify best steps to find the source and eliminate this RIB failure in red below. Full show run from both r1 and r5 routers are attached.
First step is that I go to the next hop (150.4.5.5) indicated at the rib failure. Then I compared BGP and EIGRP statements there. Is the reason for the rib failure because I have 155.4.0.0 and 155.4.0.0/24 advertised under eigrp and bgp?

Rack4R5#

Marlon

Basically yes, because IBGP AD is 200 and EIGRP AD is 90 (Internal) and 170 (External). So the BGP route cannot be inserted into the routing table because the EIGRP route is preferred and in the route table.

If you run "sh ip bgp rib-failure" on the router it should give you an idea why it was not installed in the routing table.

Edit - note that just because it failed to install in the routing table, this will not stop the BGP process from advertising this route to other BGP peers. If you don't want this happening use the "bgp suppress-inactive" command.

Jon

Just trying to reproduce this on a very small scenario:
I connected two routers, R1 and R2. I advertised the loopback network via iBGP and via EIGRP on both routers. As you can see in red, EIGRP as expected installed that on the routing table.

Question:Any idea why I did not get the RIB failure in this case? Very curious.

As you can see, the EIGRP

R1#sho run int lo 0
Building configuration...

Current configuration : 67 bytes
!
interface Loopback0
ip address 192.168.1.1 255.255.255.255
end

R1#show ip bgp
BGP table version is 4, local router ID is 192.168.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 155.0.1.0/24     0.0.0.0                  0         32768 i                     <== I got no RIB failure even though routes are advertised in both EIGRP and BGP.
* i                 155.0.1.2                0    100      0 i
* i192.168.1.0      155.0.1.2                0    100      0 i
*>                  0.0.0.0                  0         32768 i

R1#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
       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 - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
       * - candidate default, U - per-user static route, o - ODR
       P - periodic downloaded static route

Gateway of last resort is not set

     155.0.0.0/24 is subnetted, 1 subnets
C       155.0.1.0 is directly connected, FastEthernet1/0
     192.168.1.0/32 is subnetted, 2 subnets
C       192.168.1.1 is directly connected, Loopback0
D       192.168.1.2 [90/156160] via 155.0.1.2, 00:07:55, FastEthernet1/0
R1#

R2#show run | b eigrp
router eigrp 100
network 155.0.1.0 0.0.0.255
network 192.168.1.2 0.0.0.0
no auto-summary
no eigrp log-neighbor-changes
!
router bgp 100
bgp log-neighbor-changes
network 155.0.1.0 mask 255.255.255.0
network 192.168.1.0
neighbor 155.0.1.1 remote-as 100
!
ip classless
no ip http server
ip pim bidir-enable
!
logging history size 500
!
line con 0
line aux 0
line vty 0 4
!
!

R2#show ip bgp
BGP table version is 3, local router ID is 192.168.1.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
* i155.0.1.0/24     155.0.1.1                0    100      0 i
*>                  0.0.0.0                  0         32768 i
* i192.168.1.0      155.0.1.1                0    100      0 i
*>                  0.0.0.0                  0         32768 i
R2#