From: Jaycee Cockburn - BCX SS (Jaycee.Cockburn@bcx.co.za)
Date: Wed Jul 27 2005 - 04:10:33 GMT-3
Hi All/SAN
As I understand...
Bullet 3
Prefer the path that was locally originated via a network or aggregate
BGP subcommand, or through redistribution from an IGP. Local paths
sourced by network or redistribute commands are preferred over local
aggregates sourced by the aggregate-address command.
>As I understand this is paths with a next-hop of 0.0.0.0 (this router),
so in other words paths(Networks) locally originated
Example
R4#sh ip bgp
BGP table version is 11, local router ID is 192.168.4.4
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
*> 9.9.9.0/24 0.0.0.0 0 100 0 ?
* i 172.16.136.66 0 100 0 i
*>i192.168.100.0/23 192.168.5.5 0 100 0 i
Bullet 5
Prefer the path with the lowest origin type: IGP is lower than EGP, and
EGP is lower than INCOMPLETE.
>As I understand this means that if the paths (networks) were not
locally originated then check the origin type
Example
R2#sh ip bgp
BGP table version is 5, local router ID is 192.168.2.2
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
* i9.9.9.0/24 172.16.136.67 0 100 0 ?
*>i 172.16.136.66 0 100 0 i
*>i192.168.100.0/23 192.168.5.5 0 100 0 I
Hope this makes sense!
Regards
JC
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
san
Sent: 27 July 2005 08:30 AM
To: lab
Subject: Bgp path selection algorithm - question
Hi,
Bgp path selection algorithm link below. bullet 3 & bullet 5 seems
to be overlapping the same criteria of "network statements is preferred
over redistribute command".
Can some one explain me, whats the difference between bullet 3 & 5.
Non Doc Cd link:
http://www.cisco.com/warp/public/459/25.shtml
Doc cd link:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/bgp.htm
Thanks in Advance
/SAN
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