From: Popgeorgiev Nikolay (nikolay.popgeorgiev@siemens.com)
Date: Wed Mar 08 2006 - 06:12:27 GMT-3
Dear Mushtaq,
I didn't go really through all your post but I can tell you how I did this thing and what problems I faced in a similar task:
I used RR in AS 100, R1 as a route reflector and R2 as its client.
Because the requirement says do't disable synchronization, in order for R1 for example to put network 20.20.20.20 into its routing table, it has to have this route known already via IGP or static or connected.
So my solution is to redistribute BGP into IGP on router R2. This is not a very clever thing to do if you have many routes coming from BGP but in this case helps :)
Try it and if I have missed something in your explanations sorry about that
Best,
Nick
-----Original Message-----
From: Mushtaq A. Khan [mailto:mak.ccie2b@gmail.com]
Sent: Wednesday, March 08, 2006 7:59 AM
To: ccielab@groupstudy.com
Subject: EBGP peer is not advertising prefixes from other EBGP peer while synchronization is enabled in Transit ASs
Hi Team,
I have a scenario as shown below.
SW2(AS200) ----(RIP)-----R2(AS100)
\
(OSPF)
\
R1(AS100)
-----(OSPF)----R6(AS600)
/
(OSPF)
/
R5(AS600)-----EIGRP-----R3(AS100)
The task is to advertise the following prefixes in BGP ONLY within their
respective ASs and these should be exchanged between all AS's.
20.20.20.20(SW2)
5.5.5.5 (R5)
6.6.6.6 (R6)
AS100 should provide transit path between the above prefixes and MUST not
disable synchronization and use minimal number of BGP speakers.
One solution to above requirement is to use BGP confederation within AS100.
I tried to solve this using route reflector and facing difficulty: I noticed
R6 is able to see all 3 prefixes in its BGP table. However, R5 and SW2 can't
see each other prefixes. I tried different options but with no luck. Anyone
has any clue to resolve this issue here.
All relevent configuration are given below:
R2#sh run | beg router bgp
router bgp 100
synchronization
bgp log-neighbor-changes
neighbor 172.16.20.10 remote-as 200
neighbor 172.16.101.1 remote-as 100
neighbor 172.16.101.1 update-source Loopback102
no auto-summary
!
R2#sh run | beg router ospf|route-map
router ospf 1
log-adjacency-changes
redistribute rip subnets
redistribute bgp 100 subnets route-map BGPtoOSPF
network 172.16.102.1 0.0.0.0 area 20
network 172.16.123.2 0.0.0.0 area 0
!
ip prefix-list BGP-Route seq 5 permit 20.20.20.0/24
!
route-map BGPtoOSPF permit 10
match ip address prefix-list BGP-Route
R2#sh ip bgp | beg Network
Network Next Hop Metric LocPrf Weight Path
* i5.5.5.0/24 172.16.35.5 0 100 0 500 i
r>i6.6.6.0/24 172.16.16.6 0 100 0 600 i
*> 20.20.20.0/24 172.16.20.10 0 0 200 i
sw2#sh ip bgp | beg Network
Network Next Hop Metric LocPrf Weight Path
*> 6.6.6.0/24 172.16.20.2 0 100 600 i
*> 20.20.20.0/24 0.0.0.0 0 32768 i
R1#sh run | beg router ospf|route-map
router ospf 1
router-id 172.16.101.1
redistribute bgp 100 subnets route-map BGPtoOSPF
!
router bgp 100
synchronization
bgp log-neighbor-changes
neighbor AS100 peer-group
neighbor AS100 remote-as 100
neighbor AS100 update-source Loopback101
neighbor AS100 route-reflector-client
neighbor 172.16.16.6 remote-as 600
neighbor 172.16.102.1 peer-group AS100
neighbor 172.16.103.1 peer-group AS100
no auto-summary
!
!
ip prefix-list BGP-Routes seq 5 permit 6.6.6.0/24
!
route-map BGPtoOSPF permit 10
match ip address prefix-list BGP-Routes
!
R1#sh ip bgp | beg Network
Network Next Hop Metric LocPrf Weight Path
r>i5.5.5.0/24 172.16.35.5 0 100 0 500 i
*> 6.6.6.0/24 172.16.16.6 0 0 600 i
r>i20.20.20.0/24 172.16.20.10 0 100 0 200 i
R6#sh ip bgp | beg Network
Network Next Hop Metric LocPrf Weight Path
*> 5.5.5.0/24 172.16.16.1 0 100 500 i
*> 6.6.6.0/24 0.0.0.0 0 32768 i
*> 20.20.20.0/24 172.16.16.1 0 100 200 i
R3#sh run | beg router ospf|route-map
router ospf 1
log-adjacency-changes
redistribute bgp 100 subnets route-map BGPtoOSPF
router bgp 100
synchronization
bgp log-neighbor-changes
neighbor 172.16.35.5 remote-as 500
neighbor 172.16.101.1 remote-as 100
neighbor 172.16.101.1 update-source Loopback103
no auto-summary
!
!
ip prefix-list BGP-Routes seq 5 permit 5.5.5.0/24
!
route-map BGPtoOSPF permit 10
match ip address prefix-list BGP-Routes
R3#sh ip bgp | beg Network
Network Next Hop Metric LocPrf Weight Path
*> 5.5.5.0/24 172.16.35.5 0 0 500 i
r>i6.6.6.0/24 172.16.16.6 0 100 0 600 i
* i20.20.20.0/24 172.16.20.10 0 100 0 200 i
R3#
R5#sh ip bgp | beg Network
Network Next Hop Metric LocPrf Weight Path
*> 5.5.5.0/24 0.0.0.0 0 32768 i
*> 6.6.6.0/24 172.16.35.3 0 100 600 i
TIA,
Mushtaq
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