Not able to ping between IBGP and EBGP Routers across an OSPF Network

[tigerpaws]

Hello,

I am trying to get my IBGP router to ping an EBGP router and vice versa across an OSPF network without success.  I have attached a diagram for your information.  I would appreciate it if you could help shed some light on the issue.  Thanks.

And below are the configuration files along with the outputs from the "show ip bgp summary, show ip bgp neighbor and show ip route".

+ Core RT

!
version 15.4
!
hostname Core-RT
!
!
ip tcp synwait-time 5

!
interface Loopback0
 description "Core Router Loopback IP Address"
 ip address 1.1.1.1 255.255.255.255
!
interface Ethernet0/0
 description "Link to RSW1"
 ip address 10.10.10.1 255.255.255.0
 ip ospf 100 area 0
!
router ospf 100
 router-id 1.1.1.1
 redistribute bgp 400 subnets
 network 10.10.10.0 0.0.0.255 area 0
!
router bgp 400
 bgp router-id 1.1.1.1
 bgp log-neighbor-changes
 bgp redistribute-internal
 network 1.1.1.1 mask 255.255.255.255
 neighbor 2.2.2.2 remote-as 400
 neighbor 2.2.2.2 update-source Loopback0
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
ip route 2.2.2.2 255.255.255.255 10.10.10.2
ip route 3.3.3.3 255.255.255.255 10.10.10.2
!

end

Core-RT#

Core-RT#sho ip bgp summary
BGP router identifier 1.1.1.1, local AS number 400
BGP table version is 4, main routing table version 4
3 network entries using 420 bytes of memory
3 path entries using 240 bytes of memory
3/3 BGP path/bestpath attribute entries using 432 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1116 total bytes of memory
BGP activity 15/12 prefixes, 29/26 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2.2.2.2         4          400      46      45        4    0    0 00:36:39        2
Core-RT#

Core-RT#sho ip bgp neigh | inc BGP
BGP neighbor is 2.2.2.2,  remote AS 400, internal link
  BGP version 4, remote router ID 2.2.2.2
  BGP state = Established, up for 00:34:34
  BGP table version 4, neighbor version 4/0

Core-RT#sho ip route

Gateway of last resort is not set

      1.0.0.0/32 is subnetted, 1 subnets
C        1.1.1.1 is directly connected, Loopback0
      2.0.0.0/32 is subnetted, 1 subnets
S        2.2.2.2 [1/0] via 10.10.10.2
      3.0.0.0/32 is subnetted, 1 subnets
S        3.3.3.3 [1/0] via 10.10.10.2
      10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C        10.10.10.0/24 is directly connected, Ethernet0/0
L        10.10.10.1/32 is directly connected, Ethernet0/0
O        10.10.30.0/24 [110/20] via 10.10.10.2, 01:40:56, Ethernet0/0
Core-RT#

+ RSW

!
version 15.1
!
hostname RSW
!
interface Loopback0
 description "Switch Loopback IP Address"
 ip address 4.4.4.4 255.255.255.255
!
interface Ethernet0/0
 description "Link to Core Router Ethernet0/0"
 no switchport
 ip address 10.10.10.2 255.255.255.0
 ip ospf 100 area 0
!
interface Ethernet0/1
 description "Link to Router #1 Ethernet0/0"
 no switchport
 ip address 10.10.30.1 255.255.255.0
 ip ospf 100 area 0
!
router ospf 100
 router-id 4.4.4.4
 network 10.10.10.0 0.0.0.255 area 0
 network 10.10.30.0 0.0.0.255 area 0
!
no ip http server
ip route 3.3.3.3 255.255.255.255 10.10.30.2
!
end

RSW#

RSW#sho ip ospf neigh

Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           1   FULL/BDR        00:00:36    10.10.30.2      Ethernet0/1
1.1.1.1           1   FULL/BDR        00:00:39    10.10.10.1      Ethernet0/0
RSW#

RSW#sho ip route

Gateway of last resort is not set

      1.0.0.0/32 is subnetted, 1 subnets
O E2     1.1.1.1 [110/1] via 10.10.10.1, 01:08:04, Ethernet0/0
      2.0.0.0/32 is subnetted, 1 subnets
O E2     2.2.2.2 [110/1] via 10.10.30.2, 01:09:19, Ethernet0/1
      3.0.0.0/32 is subnetted, 1 subnets
S        3.3.3.3 [1/0] via 10.10.30.2
      4.0.0.0/32 is subnetted, 1 subnets
C        4.4.4.4 is directly connected, Loopback0
      10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
C        10.10.10.0/24 is directly connected, Ethernet0/0
L        10.10.10.2/32 is directly connected, Ethernet0/0
C        10.10.30.0/24 is directly connected, Ethernet0/1
L        10.10.30.1/32 is directly connected, Ethernet0/1
RSW#

+ RR1

!
version 15.4
!
hostname RR1
!
ip tcp synwait-time 5
!
interface Loopback0
 description "Router #1 Loopback IP Address"
 ip address 2.2.2.2 255.255.255.255
!
interface Ethernet0/1
 description "Link to Switch"
 ip address 10.10.30.2 255.255.255.0
 ip ospf 100 area 0
!
interface Ethernet1/0
 description "Link to Router #1"
 ip address 10.10.20.2 255.255.255.0
!
router ospf 100
 router-id 2.2.2.2
 redistribute bgp 400 subnets
 network 10.10.30.0 0.0.0.255 area 0
!
router bgp 400
 bgp router-id 2.2.2.2
 bgp log-neighbor-changes
 bgp redistribute-internal
 network 2.2.2.2 mask 255.255.255.255
 neighbor 1.1.1.1 remote-as 400
 neighbor 1.1.1.1 update-source Loopback0
 neighbor 3.3.3.3 remote-as 300
 neighbor 3.3.3.3 ebgp-multihop 2
 neighbor 3.3.3.3 update-source Loopback0
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
ip route 1.1.1.1 255.255.255.255 10.10.10.1
ip route 3.3.3.3 255.255.255.255 10.10.20.1
!
end

RR1#

RR1#sho ip bgp summary
BGP router identifier 2.2.2.2, local AS number 400
BGP table version is 8, main routing table version 8
3 network entries using 420 bytes of memory
3 path entries using 240 bytes of memory
3/3 BGP path/bestpath attribute entries using 432 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1116 total bytes of memory
BGP activity 25/22 prefixes, 51/48 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
1.1.1.1         4          400      48      49        8    0    0 00:39:35        1
3.3.3.3         4          300      50      52        8    0    0 00:42:00        1
RR1#

RR1#sho ip bgp neigh | inc BGP
BGP neighbor is 1.1.1.1,  remote AS 400, internal link
  BGP version 4, remote router ID 1.1.1.1
  BGP state = Established, up for 00:40:09
  BGP table version 8, neighbor version 8/0
BGP neighbor is 3.3.3.3,  remote AS 300, external link
  BGP version 4, remote router ID 3.3.3.3
  BGP state = Established, up for 00:42:34
  BGP table version 8, neighbor version 8/0
  External BGP neighbor may be up to 2 hops away.
RR1#

RR1#sho ip route

Gateway of last resort is not set

      1.0.0.0/32 is subnetted, 1 subnets
S        1.1.1.1 [1/0] via 10.10.10.1
      2.0.0.0/32 is subnetted, 1 subnets
C        2.2.2.2 is directly connected, Loopback0
      3.0.0.0/32 is subnetted, 1 subnets
S        3.3.3.3 [1/0] via 10.10.20.1
      10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
O        10.10.10.0/24 [110/20] via 10.10.30.1, 02:11:39, Ethernet0/1
C        10.10.20.0/24 is directly connected, Ethernet1/0
L        10.10.20.2/32 is directly connected, Ethernet1/0
C        10.10.30.0/24 is directly connected, Ethernet0/1
L        10.10.30.2/32 is directly connected, Ethernet0/1
RR1#

+ NRR1

!
version 15.4
!
hostname NRR1
!
ip tcp synwait-time 5
!
interface Loopback0
 description "Router #1 Loopback IP Address"
 ip address 3.3.3.3 255.255.255.255
!
interface Ethernet1/0
 description "Link to Router #1"
 ip address 10.10.20.1 255.255.255.0
!
router bgp 300
 bgp router-id 3.3.3.3
 bgp log-neighbor-changes
 network 3.3.3.3 mask 255.255.255.255
 neighbor 2.2.2.2 remote-as 400
 neighbor 2.2.2.2 ebgp-multihop 2
 neighbor 2.2.2.2 update-source Loopback0
!
ip forward-protocol nd
!
ip route 1.1.1.1 255.255.255.255 10.10.20.2
ip route 2.2.2.2 255.255.255.255 10.10.20.2
ip route 4.4.4.4 255.255.255.255 10.10.20.2
!
end

NRR1#sho ip bgp summar
BGP router identifier 3.3.3.3, local AS number 300
BGP table version is 6, main routing table version 6
3 network entries using 420 bytes of memory
3 path entries using 240 bytes of memory
3/3 BGP path/bestpath attribute entries using 432 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1116 total bytes of memory
BGP activity 27/24 prefixes, 54/51 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2.2.2.2         4          400      50      48        6    0    0 00:40:27        2
NRR1#

NRR1#sho ip bgp neigh | inc BGP
BGP neighbor is 2.2.2.2,  remote AS 400, external link
  BGP version 4, remote router ID 2.2.2.2
  BGP state = Established, up for 00:41:03
  BGP table version 6, neighbor version 6/0
  External BGP neighbor may be up to 2 hops away.
NRR1#

NRR1#sho ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override

Gateway of last resort is not set

      1.0.0.0/32 is subnetted, 1 subnets
S        1.1.1.1 [1/0] via 10.10.20.2
      2.0.0.0/32 is subnetted, 1 subnets
S        2.2.2.2 [1/0] via 10.10.20.2
      3.0.0.0/32 is subnetted, 1 subnets
C        3.3.3.3 is directly connected, Loopback0
      4.0.0.0/32 is subnetted, 1 subnets
S        4.4.4.4 [1/0] via 10.10.20.2
      10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        10.10.20.0/24 is directly connected, Ethernet1/0
L        10.10.20.1/32 is directly connected, Ethernet1/0
NRR1#

[mrityunjay singh]

Hello Tiger,

can you change the below IP route statement on RR1.
no ip route 3.3.3.3 255.255.255.255 10.10.20.1
ip route 3.3.3.3 255.255.255.255 10.10.30.1

Its seems reverse route for 1.1.1.1 need to put on RSW or redistribute static into ospf
Share the sh ip bgp output for the routers

Thanks,

[tigerpaws]

Hello,

Please see the output from the "show ip bgp" command below:

Core-RT#sho ip bgp
BGP table version is 7, local router ID is 1.1.1.1
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
 *>  1.1.1.1/32       0.0.0.0                  0         32768 i
 r>i 2.2.2.2/32       2.2.2.2                  0    100      0 i
Core-RT#

RR1#sho ip bgp
BGP table version is 7, local router ID is 2.2.2.2
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
 r>i 1.1.1.1/32       1.1.1.1                  0    100      0 i
 *>  2.2.2.2/32       0.0.0.0                  0         32768 i
RR1#

NRR1#sho ip bgp
BGP table version is 4, local router ID is 3.3.3.3
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
 *>  3.3.3.3/32       0.0.0.0                  0         32768 i
NRR1#

BTW, I have already made the update to the RR1 based on your earlier suggestion.

Thanks,

[cofee]

When you ping 3.3.3.3 source from loop 0 of core RT " ping 3.3.3.3 source 1.1.1.1" and you will be able to ping because by default it will source the icmp packet from 10.10.10.1 and since NRR1 doesn't have a route back to 10.10.10.1 it will drop the packet. 

RR1 doesn't have this issue because it's directly connected to NRR1. Also, not sure why you have static routes for loopbacks when you are advertising them through BGP.

You don't need to make any changes to the configuration that you posted to make this work.

[tigerpaws]

Hello,

You are correct that when I pinged 3.3.3.3 sourced from 1.1.1.1 that I was able to see the echo reply without the need to change any configuration.  However, when I tried to remove the static routes as suggested, I was no longer able to ping.  The reason for the static routes to be there is to ensure that the remote peer address used for peering is reachable.

Thank you for your notes though.

[cofee]

what Georg suggested will work, but then you would have to redistribute the static route under ospf that you have configured for 3.3.3.3 on RR1 because RR1 won't install 3.3.3.3/32 in bgp rib since you have a static route and therefore it won't be advertised to Core RT.

Another way of solving this puzzle is to increase the AD of static route for 3.3.3.3/32 to 21, which is greater than ebgp AD of 20 and with that manipulation prefix 3.3.3.0/24 will be installed in bgp rib of RR1 and advertised to Core RT through iBGP and OSPF through bgp redistribution, Core RT will install prefix 3.3.3.0/24 as an OSPF external route as AD of OSPF (110) is lower than iBGP AD of 200. I am sorry if it's confusing, my intention is show that there could be multiple work around but simplest solution is always the best. 

If you simply use the directly connected interface address for ebgp peering and not loopback (loopback is beneficial for ebgp peering if you have redundant links between two ebgp neighbors) then you won't need any static routes on any router and just mutual redistribution will work as George suggested.

But if you don't want to do that then above method will work which is redistribution of static route for 3.3.3.3/32 on RR1 under the ospf process and you can remove all static routes from RT, on R1 you will only need 1 static route for 3.3.3.3/24 and same goes for NRR1 just 1 static route for RR1 loopback address.

I hope this helps.

[tigerpaws]

Hello,

Thanks for your suggestions.  I changed the AD of the static route on RR1 to 21 as suggested and noticed that the 3.3.3.3 route shows as EBGP route on RR1 when I did the "show ip route" command.  The issue is when I went back to Core-RT and tried to do an extended ping (1000 pings) to 3.3.3.3 on NRR1, the echo replies were intermittent.  It dropped after around 700 pings.  I had to do a "clear ip route *" for the ping to resume and complete. 

I also noticed that the BGP-5-ADJCHANGE notification periodically appeared on the Consoles of both RR1 and NRR1.  It looks like BGP was flapping.  What do I need to do to correct both the intermittent ping and the BGP flapping?

Thanks again

[cofee]

Behavior that you are seeing is correct. By increasing AD of static route on RR1, it is creating a chicken and egg situation because you are relying on static route for ebgp peering. The only way I can think of fixing this is to either redistribute static which was recommended earlier or use directly connected interfaces for ebgp peering and with that you can get rid of all static routes which was also suggested before. 

[cofee]

tag

[cofee]

tag

[Georg Pauwen]

Hello,

for the sake of simplicity, I would include all loopback interfaces in AS400 in the OSPF process, and get rid of all static routes except for the two between RR1 and NRR1 (in order to establish the EBGP neighbors).

Then perform mutual BGP/OSPF redistribution on RR1 only...

[tigerpaws]

Hello,

I did as suggested and still could not ping.  Thanks for your suggestion.

[Georg Pauwen · Accepted solution]

Hello,

for the sake of completeness, and since I had this labbed in GNS3, here are the working configs for all four devices. I took the unnecessary static routes and the OSPF network statements under the SPF process out, since those are redundant:

Core-RT

hostname Core-RT
!
interface Loopback0
description "Core Router Loopback IP Address"
ip address 1.1.1.1 255.255.255.255
ip ospf 100 area 0
!
interface Ethernet0/0
description "Link to RSW1"
ip address 10.10.10.1 255.255.255.0
ip ospf 100 area 0
!
router ospf 100
router-id 1.1.1.1
!
router bgp 400
bgp router-id 1.1.1.1
bgp log-neighbor-changes
network 1.1.1.1 mask 255.255.255.255
neighbor 2.2.2.2 remote-as 400
neighbor 2.2.2.2 update-source Loopback0

RSW

hostname RSW
!
interface Loopback0
description "Switch Loopback IP Address"
ip address 4.4.4.4 255.255.255.255
ip ospf 100 area 0
!
interface Ethernet0/0
description "Link to Core Router Ethernet0/0"
no switchport
ip address 10.10.10.2 255.255.255.0
ip ospf 100 area 0
!
interface Ethernet0/1
description "Link to Router #1 Ethernet0/0"
no switchport
ip address 10.10.30.1 255.255.255.0
ip ospf 100 area 0
!
router ospf 100
router-id 4.4.4.4

RR1

hostname RR1
!
interface Loopback0
description "Router #1 Loopback IP Address"
ip address 2.2.2.2 255.255.255.255
ip ospf 100 area 0
!
interface Ethernet0/1
description "Link to Switch"
ip address 10.10.30.2 255.255.255.0
ip ospf 100 area 0
!
interface Ethernet1/0
description "Link to Router #1"
ip address 10.10.20.2 255.255.255.0
!
router ospf 100
router-id 2.2.2.2
redistribute bgp 400 subnets
redistribute static subnets
!
router bgp 400
bgp router-id 2.2.2.2
bgp log-neighbor-changes
network 2.2.2.2 mask 255.255.255.255
network 10.10.20.0 mask 255.255.255.0
redistribute ospf 100
neighbor 1.1.1.1 remote-as 400
neighbor 1.1.1.1 update-source Loopback0
neighbor 3.3.3.3 remote-as 300
neighbor 3.3.3.3 ebgp-multihop 2
neighbor 3.3.3.3 update-source Loopback0
!
ip route 3.3.3.3 255.255.255.255 10.10.20.1

NRR1

hostname NRR1
!
interface Loopback0
description "Router #1 Loopback IP Address"
ip address 3.3.3.3 255.255.255.255
!
interface Ethernet1/0
description "Link to Router #1"
ip address 10.10.20.1 255.255.255.0
!
router bgp 300
bgp router-id 3.3.3.3
bgp log-neighbor-changes
network 3.3.3.3 mask 255.255.255.255
network 10.10.20.0 mask 255.255.255.0
neighbor 2.2.2.2 remote-as 400
neighbor 2.2.2.2 ebgp-multihop 2
neighbor 2.2.2.2 update-source Loopback0
!
ip route 2.2.2.2 255.255.255.255 10.10.20.2

[tigerpaws]

Hi George,

Thank you for your recommendations.  I have updated the configuration files based on what you had below and I was able to ping the Core-RT from NRR1 and vice versa.  I have a couple of follow-up questions.

1) On Core-RT when I do a "show ip route", 10.10.20.0/24 and 3.3.3.3 are advertised as E2 routes, is there a way to advertise them as standard OSPF routes?

2) On Core-RT when I do a "show ip bgp", 2.2.2.2, 3.3.3.3, 4.4.4.4, 10.10.10.0/24, 10.10.20.0/24 and 10.10.30.0/24 show as r>I which means internal RIB-failure, is there a way to correct that?

Below are the outputs from show commands:

* Core-RT

Core-RT#sho ip bgp summary
BGP router identifier 1.1.1.1, local AS number 400
BGP table version is 21, main routing table version 21
7 network entries using 980 bytes of memory
8 path entries using 640 bytes of memory
7/6 BGP path/bestpath attribute entries using 1008 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2652 total bytes of memory
BGP activity 12/5 prefixes, 13/5 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2.2.2.2         4          400      26      23       21    0    0 00:16:53        7

Core-RT#sho ip bgp
BGP table version is 21, local router ID is 1.1.1.1

     Network          Next Hop            Metric LocPrf Weight Path
 * i 1.1.1.1/32       10.10.30.1              21    100      0 ?
 *>                   0.0.0.0                  0         32768 i
 r>i 2.2.2.2/32       2.2.2.2                  0    100      0 i
 r>i 3.3.3.3/32       3.3.3.3                  0    100      0 300 i
 r>i 4.4.4.4/32       10.10.30.1              11    100      0 ?
 r>i 10.10.10.0/24    10.10.30.1              20    100      0 ?
 r>i 10.10.20.0/24    2.2.2.2                  0    100      0 i
 r>i 10.10.30.0/24    2.2.2.2                  0    100      0 ?
Core-RT#

Core-RT#sho ip route

Gateway of last resort is not set

      1.0.0.0/32 is subnetted, 1 subnets
C        1.1.1.1 is directly connected, Loopback0
      2.0.0.0/32 is subnetted, 1 subnets
O        2.2.2.2 [110/21] via 10.10.10.2, 00:28:15, Ethernet0/0
      3.0.0.0/32 is subnetted, 1 subnets
O E2     3.3.3.3 [110/20] via 10.10.10.2, 00:13:10, Ethernet0/0
      4.0.0.0/32 is subnetted, 1 subnets
O        4.4.4.4 [110/11] via 10.10.10.2, 00:16:43, Ethernet0/0
      10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
C        10.10.10.0/24 is directly connected, Ethernet0/0
L        10.10.10.1/32 is directly connected, Ethernet0/0
O E2     10.10.20.0/24 [110/1] via 10.10.10.2, 00:12:20, Ethernet0/0
O        10.10.30.0/24 [110/20] via 10.10.10.2, 00:45:54, Ethernet0/0
Core-RT#

* RSW

RSW#sho ip ospf neigh

Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           1   FULL/BDR        00:00:38    10.10.30.2      Ethernet0/1
1.1.1.1           1   FULL/DR         00:00:37    10.10.10.1      Ethernet0/0

RSW#sho ip route

Gateway of last resort is not set

      1.0.0.0/32 is subnetted, 1 subnets
O        1.1.1.1 [110/11] via 10.10.10.1, 00:17:27, Ethernet0/0
      2.0.0.0/32 is subnetted, 1 subnets
O        2.2.2.2 [110/11] via 10.10.30.2, 00:28:31, Ethernet0/1
      3.0.0.0/32 is subnetted, 1 subnets
O E2     3.3.3.3 [110/20] via 10.10.30.2, 00:13:26, Ethernet0/1
      4.0.0.0/32 is subnetted, 1 subnets
C        4.4.4.4 is directly connected, Loopback0
      10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
C        10.10.10.0/24 is directly connected, Ethernet0/0
L        10.10.10.2/32 is directly connected, Ethernet0/0
O E2     10.10.20.0/24 [110/1] via 10.10.30.2, 00:12:37, Ethernet0/1
C        10.10.30.0/24 is directly connected, Ethernet0/1
L        10.10.30.1/32 is directly connected, Ethernet0/1

* RR1

RR1#sho ip bgp summary
BGP router identifier 2.2.2.2, local AS number 400
BGP table version is 16, main routing table version 16
7 network entries using 980 bytes of memory
9 path entries using 720 bytes of memory
7/6 BGP path/bestpath attribute entries using 1008 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2732 total bytes of memory
BGP activity 10/3 prefixes, 12/3 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
1.1.1.1         4          400      24      27       16    0    0 00:17:39        1
3.3.3.3         4          300      15      19       16    0    0 00:09:41        2

RR1#sho ip bgp
BGP table version is 16, local router ID is 2.2.2.2

     Network          Next Hop            Metric LocPrf Weight Path
 *>  1.1.1.1/32       10.10.30.1              21         32768 ?
 * i                  1.1.1.1                  0    100      0 i
 *>  2.2.2.2/32       0.0.0.0                  0         32768 i
 r>  3.3.3.3/32       3.3.3.3                  0             0 300 i
 *>  4.4.4.4/32       10.10.30.1              11         32768 ?
 *>  10.10.10.0/24    10.10.30.1              20         32768 ?
 *   10.10.20.0/24    3.3.3.3                  0             0 300 i
 *>                   0.0.0.0                  0         32768 i
 *>  10.10.30.0/24    0.0.0.0                  0         32768 ?

RR1#sho ip route

Gateway of last resort is not set

      1.0.0.0/32 is subnetted, 1 subnets
O        1.1.1.1 [110/21] via 10.10.30.1, 00:12:39, Ethernet0/1
      2.0.0.0/32 is subnetted, 1 subnets
C        2.2.2.2 is directly connected, Loopback0
      3.0.0.0/32 is subnetted, 1 subnets
S        3.3.3.3 [1/0] via 10.10.20.1
      4.0.0.0/32 is subnetted, 1 subnets
O        4.4.4.4 [110/11] via 10.10.30.1, 00:17:29, Ethernet0/1
      10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
O        10.10.10.0/24 [110/20] via 10.10.30.1, 00:42:15, Ethernet0/1
C        10.10.20.0/24 is directly connected, Ethernet1/0
L        10.10.20.2/32 is directly connected, Ethernet1/0
C        10.10.30.0/24 is directly connected, Ethernet0/1
L        10.10.30.2/32 is directly connected, Ethernet0/1

* NRR1

NRR1#sho ip bgp summary
BGP router identifier 3.3.3.3, local AS number 300
BGP table version is 18, main routing table version 18
7 network entries using 980 bytes of memory
8 path entries using 640 bytes of memory
6/6 BGP path/bestpath attribute entries using 864 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2508 total bytes of memory
BGP activity 12/5 prefixes, 13/5 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2.2.2.2         4          400      20      16       18    0    0 00:10:12        6

NRR1#sho ip bgp
BGP table version is 18, local router ID is 3.3.3.3

     Network          Next Hop            Metric LocPrf Weight Path
 *>  1.1.1.1/32       2.2.2.2                 21             0 400 ?
 r>  2.2.2.2/32       2.2.2.2                  0             0 400 i
 *>  3.3.3.3/32       0.0.0.0                  0         32768 i
 *>  4.4.4.4/32       2.2.2.2                 11             0 400 ?
 *>  10.10.10.0/24    2.2.2.2                 20             0 400 ?
 *   10.10.20.0/24    2.2.2.2                  0             0 400 i
 *>                   0.0.0.0                  0         32768 i
 *>  10.10.30.0/24    2.2.2.2                  0             0 400 ?

NRR1#sho ip route

Gateway of last resort is not set

      1.0.0.0/32 is subnetted, 1 subnets
B        1.1.1.1 [20/21] via 2.2.2.2, 00:10:19
      2.0.0.0/32 is subnetted, 1 subnets
S        2.2.2.2 [1/0] via 10.10.20.2
      3.0.0.0/32 is subnetted, 1 subnets
C        3.3.3.3 is directly connected, Loopback0
      4.0.0.0/32 is subnetted, 1 subnets
B        4.4.4.4 [20/11] via 2.2.2.2, 00:10:19
      10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
B        10.10.10.0/24 [20/20] via 2.2.2.2, 00:10:19
C        10.10.20.0/24 is directly connected, Ethernet1/0
L        10.10.20.1/32 is directly connected, Ethernet1/0
B        10.10.30.0/24 [20/0] via 2.2.2.2, 00:10:19
NRR1#

[Georg Pauwen]

Hello,

on RR1, if you redistribute the static and the BGP routes into OSPF, you can specify the metric type as type 1 or type 2, so these are your options...

If you issue the command 'sh ip bgp rib-failure' the routes listed will probably tell you that the reason for the RIB failure is that they have a higher administrative distance. You can set the administrative distance manually, but then your entire redistribution becomes unpredictable...so that's not a good idea.