Alternate path in bgp table

[sanjaymathapati1111]

HI please let let me know the probable causes that BGP is not installing alternate path in its table while alternate path is available. Topology attached fyi  and not getting alternate path at R4 .

[Georg Pauwen]

Hello,

are all ASs under your control ? Check if BGP Best External feature has not been enabled:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/xe-3s/irg-xe-3s-book/bgp_best_external.html

[sanjaymathapati1111]

As per topology ( R1 is RR for AS 123) could you please tell me on which router i should enable BGP best external feature..

[Georg Pauwen]

Hello,

I actually meant for you to check if the feature was enabled. Apparently that is not the case.

The fastest way for you to get your question answered is to post the configs of all routers so we can lab it.

[paul driver]

Hello

This is due to bgp path selection criteria 

R2 will see the short test path via R4 due  those received prefixes having a shorter as path squence in it bgp table hence the routes from R4 will get installed in its rib

res

paul

[paul driver]

Hello
When you say alternate path - can you elaborate, Do you mean an alternate bgp path towards R4 from ASN 10
Are you wanting to LB between EBGP peers?

res
Paul

[sanjaymathapati1111]

As per topology two networks at R6 (125.1.0.1 and 125.2.0.2 ) are being advertised through bgp . At R4 router to reach net 125.1.0.1 and 125.2.0.2 we have two paths i.e directly through R6 and through R2 . But at R4 sh ip bgp command shows only one path i.e through R6 only .