In BGP Can we peer with neighbour learned via BGP .

eng_elamein · ‎11-05-2015

Hi All ,

Briefly I have I-BGP session between R1 lo0 & R3 lo0 that advertise Loopbacks from two routers , although I can see R3 Lo3 appeared in R1 routing table and via reverse for R3 , I can not initiate BGP session between R1 Lo1 and R3 Lo3.

debug indicated below ,

*Mar 1 05:27:37.750: BGP: 30.30.30.30 active open failed - no route to peer, open active delayed 34813ms (35000ms max, 28% jitter)

I think BGP can not estabilsh relationship with other peer learned via BGP , It shall be learned via any IGP . Is that true ?

interface Loopback0
ip address 1.1.1.1 255.255.255.255
!
interface Loopback1
ip address 10.10.10.10 255.255.255.255

!
interface FastEthernet0/0
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto

!
router bgp 1
no synchronization
bgp log-neighbor-changes
network 10.10.10.10 mask 255.255.255.255
neighbor 3.3.3.3 remote-as 1
neighbor 3.3.3.3 update-source Loopback0
neighbor 30.30.30.30 remote-as 1
neighbor 30.30.30.30 update-source Loopback1
no auto-summary
!
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 FastEthernet0/0
ip route 3.0.0.0 255.0.0.0 2.2.2.2

interface Loopback0
ip address 3.3.3.3 255.255.255.255
!
interface Loopback3
ip address 30.30.30.30 255.255.255.255

!
interface FastEthernet0/1
ip address 192.168.2.3 255.255.255.0
duplex auto
speed auto
!
router bgp 1
no synchronization
bgp log-neighbor-changes
network 30.30.30.30 mask 255.255.255.255
neighbor 1.1.1.1 remote-as 1
neighbor 1.1.1.1 update-source Loopback0
neighbor 10.10.10.10 remote-as 1
neighbor 10.10.10.10 update-source Loopback3
no auto-summary
!
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 FastEthernet0/0
ip route 1.1.1.1 255.255.255.255 FastEthernet0/1

R1#show ip route
Gateway of last resort is 0.0.0.0 to network 0.0.0.0

     1.0.0.0/32 is subnetted, 1 subnets
C       1.1.1.1 is directly connected, Loopback0
S   3.0.0.0/8 [1/0] via 2.2.2.2
     10.0.0.0/32 is subnetted, 1 subnets
C       10.10.10.10 is directly connected, Loopback1
C   192.168.1.0/24 is directly connected, FastEthernet0/0
     30.0.0.0/32 is subnetted, 1 subnets
B       30.30.30.30 [200/0] via 3.3.3.3, 00:18:01
S*   0.0.0.0/0 is directly connected, FastEthernet0/0

R3#show ip route
Gateway of last resort is not set

     1.0.0.0/32 is subnetted, 1 subnets
S       1.1.1.1 is directly connected, FastEthernet0/1
     3.0.0.0/32 is subnetted, 1 subnets
C       3.3.3.3 is directly connected, Loopback0
     10.0.0.0/32 is subnetted, 1 subnets
B       10.10.10.10 [200/0] via 1.1.1.1, 00:19:34
C   192.168.2.0/24 is directly connected, FastEthernet0/1
     30.0.0.0/32 is subnetted, 1 subnets
C       30.30.30.30 is directly connected, Loopback3

eng_elamein · ‎11-05-2015

R1#       show ip bgp summary
BGP router identifier 1.1.1.1, local AS number 1
BGP table version is 5, main routing table version 5
2 network entries using 240 bytes of memory
2 path entries using 104 bytes of memory
3/2 BGP path/bestpath attribute entries using 372 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
Bitfield cache entries: current 1 (at peak 1) using 32 bytes of memory
BGP using 748 total bytes of memory
BGP activity 3/1 prefixes, 3/1 paths, scan interval 60 secs

Neighbor        V    AS MsgRcvd MsgSent   TblVer InQ OutQ Up/Down State/PfxRcd
3.3.3.3         4     1     254     252        5    0    0 03:52:59        1
30.30.30.30     4     1       0       0        0    0    0 never    Active
R1#