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New Member

no best path(BGP)

what is wrong?

ping test is good:both path

======================

C6509--R#sh ip bgp 10.10.6.19

BGP routing table entry for 10.10.0.0/16, version 0

Paths: (2 available, no best path)

Not advertised to any peer

1000 2000, (received-only)

200.100.200.150 from 200.100.200.150 (200.100.200.150)

Origin IGP, localpref 100, valid, external

Community: 312354000

3000 2000, (received-only)

150.100.100.109 from 150.100.100.109 (172.30.51.171)

Origin IGP, localpref 100, valid, external

Community: 248119000

=========================

router bgp 5000

no synchronization

bgp log-neighbor-changes

network 220.1.54.0

redistribute static

neighbor 150.100.100.109 remote-as 3000

neighbor 150.100.100.109 ebgp-multihop 255

neighbor 150.100.100.109 soft-reconfiguration inbound

neighbor 150.100.100.109 route-map ASPREPEND out

neighbor 150.100.100.109 filter-list 10 in

neighbor 150.100.100.109 filter-list 100 out

neighbor 200.100.200.150 remote-as 1000

neighbor 200.100.200.150 ebgp-multihop 255

neighbor 200.100.200.150 soft-reconfiguration inbound

neighbor 200.100.200.150 filter-list 20 in

neighbor 200.100.200.150 filter-list 100 out

no auto-summary

!

ip classless

ip route 0.0.0.0 0.0.0.0 10.10.10.1

ip route 0.0.0.0 0.0.0.0 20.20.20.1

ip route 220.1.54.0 255.255.254.0 100.246.1.1

ip route 150.100.100.109 255.255.255.255 20.20.20.1

ip route 200.100.200.150 255.255.255.255 10.10.10.1

route-map ASPREPEND permit 10

set as-path prepend 5000 5000

ip as-path access-list 10 permit ^(3000_)+$

ip as-path access-list 20 permit ^(1000_)+$

ip as-path access-list 100 permit ^$

3 REPLIES
Cisco Employee

Re: no best path(BGP)

Both paths are in "received-only" mode, which means that they have been filtered by an inbound policy but kept because "soft-reconfiguration inbound" is configured.

The as-path ACLs 10 and 20 are not allowing the as-paths received from your two neighbors.

as-path acl 10 only allows one or more repetition of ASN 3000, which is different than "3000 2000" received from 150.100.100.109.

as-path acl 20 only allows one or more repetition of ASN 1000, which is different than "1000 2000" received from 200.100.200.150.

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

no best path(BGP)

Dear Harold, I have solved my issue by seeing you comment. Thanks.

Cisco Employee

Re: no best path(BGP)

Hi,

I'm glad to hear I could help.

Thanks for the comment

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
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