From: NITIN NITIN (ccie_study_123@yahoo.com)
Date: Sat Aug 11 2007 - 11:56:55 ART
Hi ,
Thanks for reply
please suggest why R2 is selcted and notr R1
wht is criteria for this ??
and I thought next-hop-self is for ibgp peers ----is it valid option for ebgp peers also.....coz to ebgp peer automatically next hop is changed ( peering ip-address) when update go
Thanks
Herbert Maosa <asawilunda@googlemail.com> wrote:
Hi,
BGP does not change the next hop on a Multi-access network unless explicitly configured to do so through next-hop self. If the BGP speaker determines that both the sending and the intended neighbor are reached through the same interface, it leaves the next hop unchanged for optimum routing ( needless to make an extra unneccessary hop through this router ) as these neighbors can reach each other directly on the multi-access network.
Herbert.
On 8/11/07, NITIN NITIN <ccie_study_123@yahoo.com> wrote: Hi experts,
R5 and R1 and R2 are in a broadcast domain
next hop is 152.1.125.2 for routes via R1
DON't know why
Please suggest ????????
R5 - 152.1.125.5 ip
R1 - 152.1.125.1 ip
R2 - 152.1.125.2 ip
Rack1R5#sh ip bgp regexp _254$
BGP table version is 14, local router ID is 150.1.5.5
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
* 205.90.31.0 152.1.125.2 0 200 254 ?
*> 152.1.125.2 0 200 254 ?
* 220.20.3.0 152.1.125.2 0 200 254 ?
*> 152.1.125.2 0 200 254 ?
* 222.22.2.0 152.1.125.2 0 200 254 ?
*> 152.1.125.2 0 200 254 ?
Rack1R5#
R5 in AS 100
R1 and R2 in AS 200
R5
router bgp 100
no synchronization
bgp router-id 150.1.5.5
bgp log-neighbor-changes
neighbor 150.1.4.4 remote-as 100
neighbor 150.1.4.4 update-source Loopback0
neighbor 152.1.125.1 remote-as 200
neighbor 152.1.125.2 remote-as 200
no auto-summary
!
R1
router bgp 1000
no synchronization
bgp router-id 150.1.1.1
bgp log-neighbor-changes
bgp confederation identifier 200
bgp confederation peers 3000
neighbor 152.1.123.3 remote-as 3000
neighbor 152.1.125.5 remote-as 100
no auto-summary
R2
router bgp 2000
no synchronization
bgp router-id 150.1.2.2
bgp log-neighbor-changes
bgp confederation identifier 200
bgp confederation peers 3000
neighbor 152.1.123.3 remote-as 3000
neighbor 152.1.125.5 remote-as 100
no auto-summary
Regards
---------------------------------
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This archive was generated by hypermail 2.1.4 : Sat Sep 01 2007 - 11:32:10 ART