From: Xiaobo Zhu (xiaobo@zhu.net)
Date: Wed Dec 31 2008 - 06:03:39 ARST
Hi,
Sorry for that long subject, hope I've described the question clearly with
it. I will explain it in detail anyway.
Here is the scenario.
(
6.6.6.6/24)R6(192.168.16.0/24)R1(192.168.12.0/24)R2(192.168.23.0/24)R3(192.168.35.0/24)R5(5.5.5.5/24
)
and R2 has a loopback interface with IP address 2.2.2.2/24
R6 is in BGP AS 6, R1 and R2 are in BGP AS 12, R3 is in BGP AS 3 and R5 is
in BGP AS 5.
When I advertise R5's loopback interface to the network with the command
network 5.5.5.0 mask 255.255.255.0, R3 can install the entry with no
difficulty, but R2 failed.
It seems that R3 does not change the next hop of 5.5.5.0/24 entry to
192.168.23.3(I will paste the output below).
The question is just as the subject of this email, as R1, R2 and R3 are in
the same are in the same confederation, R3 should take R2 as an EBGP
neighbor in its point of view. Why R3 does not change the next hop of the
5.5.5.0/24 entry when forward it to R2.
Many thanks and best wishes for the coming new year!
Cheers, Xiaobo
The following are the running configuration.
===============================
R1#show running-config | begin router bgp
router bgp 12
no synchronization
bgp log-neighbor-changes
bgp confederation identifier 2
neighbor 192.168.12.2 remote-as 12
neighbor 192.168.12.2 next-hop-self
neighbor 192.168.16.6 remote-as 6
no auto-summary
--------------------------------------------------------------
R2#show running-config | begin router bgp
router bgp 12
no synchronization
bgp log-neighbor-changes
bgp confederation identifier 2
bgp confederation peers 3
network 2.2.2.0 mask 255.255.255.0
neighbor 192.168.12.1 remote-as 12
neighbor 192.168.12.1 next-hop-self
neighbor 192.168.23.3 remote-as 3
no auto-summary
--------------------------------------------------------------
R3#show running-config | begin router bgp
router bgp 3
no synchronization
bgp log-neighbor-changes
bgp confederation identifier 2
bgp confederation peers 12
neighbor 192.168.23.2 remote-as 12
neighbor 192.168.35.5 remote-as 5
no auto-summary
--------------------------------------------------------------
R5#show running-config | begin router bgp
router bgp 5
no synchronization
bgp log-neighbor-changes
network 5.5.5.0 mask 255.255.255.0
neighbor 192.168.35.3 remote-as 2
no auto-summary
--------------------------------------------------------------
R6#show running-config | begin router b
router bgp 6
no synchronization
bgp log-neighbor-changes
network 6.6.6.0 mask 255.255.255.0
neighbor 192.168.16.1 remote-as 2
no auto-summary
--------------------------------------------------------------
R2#show ip bgp
BGP table version is 5, 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
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2.2.2.0/24 0.0.0.0 0 32768 i
* 5.5.5.0/24 192.168.35.5 0 100 0 (3) 5 i
*>i6.6.6.0/24 192.168.12.1 0 100 0 6 i
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