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New Member

Two Identical Routes in BGP

Hi,

there is a example of load balancing in SAM HALABI. As per the route selection policy , the few last checks are ...

the older ebgp route is prefered and the lowest router id is prefered.

Does the loadbalancing in case of two identical routes received ober eBGP from two peer in a neighboring AS , mandatorily requires "maximum-path XX"...or it will work without that command too..

Can somebody comment..?

Thx

G

4 REPLIES
Cisco Employee

Re: Two Identical Routes in BGP

That is correct. "maximum-path 2" is required to load-balance between two equal paths received from neighbors in the same peers AS.

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

Re: Two Identical Routes in BGP

is it bcoz out of two ebgp routes , the oldes will be prefered...

Thx

G

Purple

Re: Two Identical Routes in BGP

By default, BGP will only install one router as in the routing table. In the case of EBGP, that will be the oldest route. If maximum-paths is set to 2, for example, the age of the routes will not be considered and both the routes will be installed in the routing table. The BGP table (sh ip bgp) will still show the older route as the best but it will still install both routes in the routing table.

Hope that helps - pls do rate the post if it does.

Paresh

New Member

Re: Two Identical Routes in BGP

Thx Paresh,

Now I want to advertise both routes which kept in my routing table with maximum-paths command...

Any possibility..

Thx,

G

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