Re: BGP reflector Non-directed client

From: steve.skinner@uk.pwc.com
Date: Wed Mar 09 2005 - 12:15:59 GMT-3


you are getting a rib failure because the routes in your bgp table are
already advertised via an IGP

as you can see on R1

R1 BGP table

   Network Next Hop Metric LocPrf Weight Path
r>i197.68.1.0 3.3.2.2 100 0 4 254 i
r>i197.68.4.0 3.3.2.2 100 0 4 254 i
r>i197.68.5.0 3.3.2.2 100 0 4 254 i
*> 200.200.200.0 0.0.0.0 0 32768 i
r>i200.200.201.0 3.3.5.5 0 100 0 6 i

R1 route table
O E2 197.68.1.0/24 [110/2000] via 3.3.125.2, 00:17:26, Serial0
O E2 197.68.5.0/24 [110/2000] via 3.3.125.2, 00:17:26, Serial0
O E2 197.68.4.0/24 [110/2000] via 3.3.125.2, 00:17:26, Serial0
C 200.200.200.0/24 is directly connected, Loopback200
O E2 200.200.201.0/24 [110/2000] via 3.3.125.5, 00:17:44, Serial0
     3.0.0.0/24 is subnetted, 8 subnets

check your level of IOS as this is dependant on the level

 CSCdx26714
>
> 1. Symptom :
>
> If the prefix get Rib-Failre when installing into bgp table because of
> there is already has a prefix in the routing table with a prefered
admin
> distance (like already learnd by ospf), then this prefix should not be
> advertised to other bgp peers unless the next-hop is the same as the
> prefix
> in the ip routing table.
> But the behavior is that even if the next-hop is the same, this
> prefix still
> does not advertise to it's bgp peers.
>
> 2. Conditions :
>
> You should see the bgp prefix get a "Rib-Failure" in the output of
> "show ip bgp <x.x.x.x> ". This will confirm that this prefix fails to
> install into the routing table. Then check the next-hop for the bgp
> prefix
> and the prefix that already in the ip table (it's ospf in this ddts).
If
> they are the same, then bgp should still advertise this prfix to it's
bgp
> peers.
>
> 3. Workaround :
>
> Thers is not workaround for this problem.

Stephen Skinner

                                                                                                                                   
                      "Dillon Yang"
                      <gzdillon@hotmail.c To: "Group Study" <ccielab@groupstudy.com>
                      om> cc:
                      Sent by: Subject: BGP reflector Non-directed client
                      nobody@groupstudy.c
                      om
                                                                                                                                   
                                                                                                                                   
                      09/03/2005 13:15
                                                                                                                                   
                                                                                                                                   
                      Please respond to
                      "Dillon Yang"
                                                                                                                                   
                                                                                                                                   

Hi, folks:

In a case, the topology is :

R1(reflector)
|
FR
|
R5(Hub)----------R6(AS6)
|
FR
|
R2---------------R4(AS4)

R1, R2, R5 are in AS 3, The R2 and R5 can not receive external routes from
R1. Why?

TIA
dillon

***************************************************
Changing Router to 3.3.1.1
r1#s ip bgp
BGP table version is 10, local router ID is 3.3.1.1
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
r>i197.68.1.0 3.3.2.2 100 0 4 254 i
r>i197.68.4.0 3.3.2.2 100 0 4 254 i
r>i197.68.5.0 3.3.2.2 100 0 4 254 i
*> 200.200.200.0 0.0.0.0 0 32768 i
r>i200.200.201.0 3.3.5.5 0 100 0 6 i

s ip bgp 197.68.1.0
BGP routing table entry for 197.68.1.0/24, version 7
Paths: (1 available, best #1, table Default-IP-Routing-Table,
RIB-failure(17))
  Not advertised to any peer
  4 254, (Received from a RR-client)
    3.3.2.2 (metric 801) from 3.3.2.2 (3.3.2.2)
      Origin IGP, localpref 100, valid, internal, best

s ip bgp 200.200.201.0
BGP routing table entry for 200.200.201.0/24, version 3
Paths: (1 available, best #1, table Default-IP-Routing-Table,
RIB-failure(17))
  Not advertised to any peer
  6, (Received from a RR-client)
    3.3.5.5 (metric 801) from 3.3.5.5 (3.3.2.2)
      Origin IGP, metric 0, localpref 100, valid, internal, best

r1#s ip os nei

Neighbor ID Pri State Dead Time Address Interface
3.3.5.5 1 FULL/DR 00:01:53 3.3.125.5 Serial0

s ip route | be Gateway
Gateway of last resort is not set

C 200.200.200.0/24 is directly connected, Loopback200
O E2 200.200.201.0/24 [110/2000] via 3.3.125.5, 00:17:44, Serial0
     3.0.0.0/24 is subnetted, 8 subnets
C 3.3.1.0 is directly connected, Loopback0
O 3.3.2.0 [110/801] via 3.3.125.2, 00:34:03, Serial0
O E2 3.3.4.0 [110/5000] via 3.3.125.2, 00:34:03, Serial0
O 3.3.5.0 [110/801] via 3.3.125.5, 00:34:03, Serial0
O E2 3.3.6.0 [110/2000] via 3.3.125.5, 00:34:03, Serial0
O E2 3.3.24.0 [110/4000] via 3.3.125.2, 00:34:03, Serial0
O E2 3.3.56.0 [110/2000] via 3.3.125.5, 00:34:03, Serial0
C 3.3.125.0 is directly connected, Serial0
     4.0.0.0/24 is subnetted, 1 subnets
O E2 4.4.4.0 [110/2000] via 3.3.125.5, 00:34:03, Serial0
O E2 197.68.1.0/24 [110/2000] via 3.3.125.2, 00:17:26, Serial0
O E2 197.68.5.0/24 [110/2000] via 3.3.125.2, 00:17:26, Serial0
O E2 197.68.4.0/24 [110/2000] via 3.3.125.2, 00:17:26, Serial0
O E2 192.3.2.0/24 [110/2000] via 3.3.125.5, 00:34:03, Serial0
     150.100.0.0/24 is subnetted, 1 subnets
O E2 150.100.2.0 [110/5000] via 3.3.125.2, 00:34:03, Serial0

s run | be router bgp
router bgp 3
 no synchronization
 bgp router-id 3.3.1.1
 bgp log-neighbor-changes
 network 200.200.200.0
 neighbor 3.3.2.2 remote-as 3
 neighbor 3.3.2.2 update-source Loopback0
 neighbor 3.3.2.2 route-reflector-client
 neighbor 3.3.5.5 remote-as 3
 neighbor 3.3.5.5 update-source Loopback0
 neighbor 3.3.5.5 route-reflector-client
 no auto-summary

***************************************************
Changing Router to 3.3.2.2
s ip bgp 197.68.1.0
BGP routing table entry for 197.68.1.0/24, version 2
Paths: (1 available, best #1, table Default-IP-Routing-Table)
  Advertised to non peer-group peers:
  3.3.1.1
  4 254
    3.3.4.4 (metric 1) from 3.3.4.4 (3.3.4.4)
      Origin IGP, localpref 100, valid, external, best

s ip bgp 200.200.201.0

% Network not in table
r2#s ip os nei

Neighbor ID Pri State Dead Time Address Interface
3.3.5.5 1 FULL/DR 00:01:43 3.3.125.5 Serial0
r2#

s ip route | be Gateway
Gateway of last resort is not set

O E2 200.200.200.0/24 [110/2000] via 3.3.125.1, 00:30:36, Serial0
O E2 200.200.201.0/24 [110/2000] via 3.3.125.5, 00:17:55, Serial0
     3.0.0.0/24 is subnetted, 8 subnets
O 3.3.1.0 [110/801] via 3.3.125.1, 00:30:36, Serial0
C 3.3.2.0 is directly connected, Loopback0
R 3.3.4.0 [120/1] via 3.3.24.4, 00:00:26, Serial1
O 3.3.5.0 [110/801] via 3.3.125.5, 00:30:36, Serial0
O E2 3.3.6.0 [110/2000] via 3.3.125.5, 00:30:36, Serial0
C 3.3.24.0 is directly connected, Serial1
O E2 3.3.56.0 [110/2000] via 3.3.125.5, 00:30:36, Serial0
C 3.3.125.0 is directly connected, Serial0
     4.0.0.0/24 is subnetted, 1 subnets
O E2 4.4.4.0 [110/2000] via 3.3.125.5, 00:30:36, Serial0
B 197.68.1.0/24 [20/0] via 3.3.4.4, 00:17:37
B 197.68.5.0/24 [20/0] via 3.3.4.4, 00:17:37
B 197.68.4.0/24 [20/0] via 3.3.4.4, 00:17:37
O E2 192.3.2.0/24 [110/2000] via 3.3.125.5, 00:30:36, Serial0
     150.100.0.0/24 is subnetted, 1 subnets
R 150.100.2.0 [120/1] via 3.3.24.4, 00:00:26, Serial1

s run | be router bgp
router bgp 3
 no synchronization
 bgp router-id 3.3.2.2
 bgp log-neighbor-changes
 neighbor 3.3.1.1 remote-as 3
 neighbor 3.3.1.1 update-source Loopback0
 neighbor 3.3.1.1 next-hop-self
 neighbor 3.3.4.4 remote-as 4
 neighbor 3.3.4.4 ebgp-multihop 255
 neighbor 3.3.4.4 update-source Loopback0
 no auto-summary
!

***************************************************
Changing Router to 3.3.5.5
s ip bgp 197.68.1.0

% Network not in table

s ip bgp 200.200.201.0
BGP routing table entry for 200.200.201.0/24, version 2
Paths: (1 available, best #1, table Default-IP-Routing-Table)
  Advertised to non peer-group peers:
  3.3.1.1
  6
    3.3.6.6 (metric 409600) from 3.3.6.6 (3.3.6.6)
      Origin IGP, metric 0, localpref 100, valid, external, best
r5#s ip os nei

Neighbor ID Pri State Dead Time Address Interface
3.3.1.1 0 FULL/DROTHER 00:01:45 3.3.125.1 Serial0
3.3.2.2 0 FULL/DROTHER 00:01:45 3.3.125.2 Serial0
r5#

s ip route | be Gateway
Gateway of last resort is not set

O E2 200.200.200.0/24 [110/2000] via 3.3.125.1, 00:34:25, Serial0
B 200.200.201.0/24 [20/0] via 3.3.6.6, 00:18:05
     3.0.0.0/24 is subnetted, 8 subnets
O 3.3.1.0 [110/801] via 3.3.125.1, 00:34:25, Serial0
O 3.3.2.0 [110/801] via 3.3.125.2, 00:34:25, Serial0
O E2 3.3.4.0 [110/5000] via 3.3.125.2, 00:34:25, Serial0
C 3.3.5.0 is directly connected, Loopback0
D 3.3.6.0 [90/409600] via 3.3.56.6, 00:36:21, Ethernet0
O E2 3.3.24.0 [110/4000] via 3.3.125.2, 00:34:25, Serial0
C 3.3.56.0 is directly connected, Ethernet0
C 3.3.125.0 is directly connected, Serial0
     4.0.0.0/24 is subnetted, 1 subnets
D EX 4.4.4.0 [170/26163200] via 3.3.56.6, 00:36:21, Ethernet0
O E2 197.68.1.0/24 [110/2000] via 3.3.125.2, 00:17:48, Serial0
O E2 197.68.5.0/24 [110/2000] via 3.3.125.2, 00:17:48, Serial0
O E2 197.68.4.0/24 [110/2000] via 3.3.125.2, 00:17:48, Serial0
D 192.3.2.0/24 [90/2195456] via 3.3.56.6, 00:36:21, Ethernet0
     150.100.0.0/24 is subnetted, 1 subnets
O E2 150.100.2.0 [110/5000] via 3.3.125.2, 00:34:25, Serial0

s run | be router bgp
router bgp 3
 no synchronization
 bgp router-id 3.3.2.2
 bgp log-neighbor-changes
 neighbor 3.3.1.1 remote-as 3
 neighbor 3.3.1.1 update-source Loopback0
 neighbor 3.3.1.1 next-hop-self
 neighbor 3.3.6.6 remote-as 6
 neighbor 3.3.6.6 ebgp-multihop 255
 neighbor 3.3.6.6 update-source Loopback0
 no auto-summary
end
=====================End==================



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