From: dayo@ademuyiwa.com
Date: Mon Sep 03 2007 - 06:18:27 ART
HI Guys,
Please i have a problem with IGP metric with BGP path selection. Please i
will appreciate your comment
How can I influence the path with the ebgp speaker with the highest IGP
metric to talk to its ebgp neighbor to use its path for the BGP next hop.
the bgp R4 below is using R6 3.3.6.6 (metric 3) with the lower metric to
reach 200.20.102.1 But I need to influence R2 so that R4 will prefer it for
the best.
How can do it? because R4 is using IGP metric to choose its best path
R2 and R6 area talking ebgp to R4.
R4#sh ip bgp 200.20.105.1
BGP routing table entry for 200.20.105.1/32, version 12
Paths: (2 available, best #2, table Default-IP-Routing-Table)
Flag: 0x820
Advertised to update-groups:
1 2
20
3.3.2.2 (metric 20) from 3.3.2.2 ( 3.3.2.2)
Origin IGP, localpref 100, valid, external
20
3.3.6.6 (metric 3) from 3.3.6.6 (3.3.6.6)
Origin IGP, localpref 100, valid, external, best
R4#
R4#sh ip bgp 200.20.102.1
BGP routing table entry for 200.20.102.1/32, version 14
Paths: (2 available, best #1, table Default-IP-Routing-Table)
Flag: 0x920
Advertised to update-groups:
1 2
20
3.3.6.6 (metric 3) from 3.3.6.6 ( 3.3.6.6)
Origin IGP, localpref 100, valid, external, best
20
3.3.2.2 (metric 20) from 3.3.2.2 (3.3.2.2)
Origin IGP, metric 0, localpref 100, valid, external
R4#
R4#sh ip bgp
BGP table version is 14, local router ID is 3.3.4.4
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
*>i200.10.101.1/32 3.3.1.1 0 100 0 i
*>i200.10.103.1/32 3.3.3.3 0 100 0 i
*> 200.10.104.1/32 0.0.0.0 0 32768 i
*> 200.20.102.1/32 3.3.6.6 0 20 i
* 3.3.2.2 0 0 20 i
* 200.20.105.1/32 3.3.2.2 0 20 i
*> 3.3.6.6 0 20 i
* 200.20.106.1/32 3.3.2.2 0 20 i
*> 3.3.6.6 0 0 20 i
R4#
router bgp 10
no synchronization
bgp router-id 3.3.4.4
bgp log-neighbor-changes
network 200.10.104.1 mask 255.255.255.255
neighbor 3.3.1.1 remote-as 10
neighbor 3.3.1.1 update-source Loopback0
neighbor 3.3.1.1 route-reflector-client
neighbor 3.3.2.2 remote-as 20
neighbor 3.3.2.2 ebgp-multihop 20
neighbor 3.3.2.2 update-source Loopback0
neighbor 3.3.3.3 remote-as 10
neighbor 3.3.3.3 update-source Loopback0
neighbor 3.3.3.3 route-reflector-client
neighbor 3.3.6.6 remote-as 20
neighbor 3.3.6.6 ebgp-multihop 20
neighbor 3.3.6.6 update-source Loopback0
no auto-summary
R2#
router bgp 20
no synchronization
bgp router-id 3.3.2.2
bgp log-neighbor-changes
network 200.20.102.1 mask 255.255.255.255
neighbor 3.3.4.4 remote-as 10
neighbor 3.3.4.4 ebgp-multihop 20
neighbor 3.3.4.4 update-source Loopback0
neighbor 3.3.4.4 next-hop-self
neighbor 3.3.4.4 route-map good in
neighbor 3.3.4.4 route-map got out
neighbor 3.3.5.5 remote-as 20
neighbor 3.3.5.5 update-source Loopback0
neighbor 3.3.6.6 remote-as 20
neighbor 3.3.6.6 update-source Loopback0
no auto-summary
!
R6#
router bgp 20
no synchronization
bgp router-id 3.3.6.6
bgp log-neighbor-changes
network 200.20.106.1 mask 255.255.255.255
neighbor 3.3.2.2 remote-as 20
neighbor 3.3.2.2 update-source Loopback0
neighbor 3.3.4.4 remote-as 10
neighbor 3.3.4.4 ebgp-multihop 20
neighbor 3.3.4.4 update-source Loopback0
neighbor 3.3.5.5 remote-as 20
neighbor 3.3.5.5 update-source Loopback0
no auto-summary
!
thanks
This archive was generated by hypermail 2.1.4 : Sat Oct 06 2007 - 12:01:09 ART