Just replicated your scenario:
Top:
R1----R4----R3
R1 lo0: 172.16.31.1
R1---R4: 172.16.4.X /24
R4---R3: 172.16.3.X /24
R4 lo0: 172.16.144.1
IP OSPF running on R1,4,3; area 0
R3 BGP config:
router bgp 65001
neighbor 172.16.31.1 remote-as 65001
neighbor 172.16.31.1 update-source Loopback0
R1 BGP config:
router bgp 65001
neighbor 172.16.144.1 remote-as 65001
neighbor 172.16.144.1 update-source Loopback0
OSPF routes:
r1#sh ip rou ospf
172.16.0.0/16 is variably subnetted, 6 subnets, 2 masks
O 172.16.144.1/32 [110/75] via 172.16.4.4, 00:08:44, Serial0.2
O 172.16.128.0/24 [110/84] via 172.16.4.4, 00:08:44, Serial0.2
O 172.16.242.4/32 [110/65] via 172.16.4.4, 00:08:44, Serial0.2
O 172.16.3.0/24 [110/74] via 172.16.4.4, 00:08:44, Serial0.2
IBGP relationship:
r1#b
BGP router identifier 172.16.31.1, local AS number 65001
BGP table version is 1, main routing table version 1
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
State/PfxRcd
172.16.144.1 4 65001 8 8 1 0 0 00:05:13 0
""Richard Chang"" <[EMAIL PROTECTED]> wrote in message
98prh1$5ab$[EMAIL PROTECTED]">news:98prh1$5ab$[EMAIL PROTECTED]...
> 1. I did have "update-source" command...
> 2. loopback interfaces are pinging on both routers...
>
> I also wish that it is true that there is no limitation for ibgp
multihop...
>
> However, based on my following test, the only conclusion I came up with is
> that either I missed something that's really obvious or Cisco does not
> support ibgp multihop.
>
> R2:
> interface Loopback0
> ip address 2.2.2.2 255.255.255.0
> no ip directed-broadcast
>
> router bgp 65001
> no synchronization
> bgp confederation identifier 100
> neighbor 3.3.3.3 remote-as 65001
> neighbor 3.3.3.3 update-source Loopback0
>
> R2#ping 3.3.3.3
>
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
> !!!!!
>
> R2#show ip bgp summ
> BGP router identifier 2.2.2.2, local AS number 65001
> BGP table version is 1, main routing table version 1
>
> Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
> State/PfxRcd
> 3.3.3.3 4 65001 0 0 0 0 0 never Active
>
> R3:
> interface Loopback0
> ip address 3.3.3.3 255.255.255.0
> no ip directed-broadcast
>
> router bgp 65001
> no synchronization
> bgp confederation identifier 100
> neighbor 2.2.2.2 remote-as 65001
> neighbor 2.2.2.2 update-source Loopback0
>
> R3#ping 2.2.2.2
>
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
> !!!!!
>
> "Raul Camacho" <[EMAIL PROTECTED]> wrote in message
> 98pha2$fop$[EMAIL PROTECTED]">news:98pha2$fop$[EMAIL PROTECTED]...
> > There is no requirement for IBGP neigbors to be directly connected.
Make
> > sure that you have the routes for all of the intermediate links and the
> > loopbacks in your routing table first.
> >
> > ""Richard Chang"" <[EMAIL PROTECTED]> wrote in message
> > 98p8ls$chl$[EMAIL PROTECTED]">news:98p8ls$chl$[EMAIL PROTECTED]...
> > > For EBGP, you can use the ebgp-multihop command when the neighbors are
> not
> > > directly-connected. I was just wondering whether there is a similar
> > > work-around that anyone know of for IBGP.
> > >
> > > Basically, I am using loopback interfaces on these two routers and
they
> > have
> > > to go through another hop before hitting each other. I configured IBGP
> on
> > > these two routers with those loopback addresses and found out that the
> BGP
> > > session can't be formed...
> > >
> > > Thanks
> > >
> > > Richard
> > >
> > >
> > > _________________________________
> > > FAQ, list archives, and subscription info:
> > http://www.groupstudy.com/list/cisco.html
> > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
> > >
> >
> >
> > _________________________________
> > FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
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> >
>
>
> _________________________________
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