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Load balancing with failover on BGP routes

Hi every one.

I have a situation like below

We have Router A which is connected to sites B,C & D with mpls via ISP1, in a hub & spoke manner.

Now we are planning to add 1 more ISP2 which will provide connectivity to Site D only for now.

Site A and Site D is on BGP route.

Now My question is If I want to configure Load balance on site A and site D for both ISP what and how it will be ?

notice*- Site A is a HUB location all services Like Internet and Others are running Through Site A only.

"We need to use both ISP at the same time and also a fail over if on link goes down, at least Site D will be reachable."

What will be best Solution for this.. Which feature I can use, Route Policy ? IP sla, HSRP, GLBP , or any thing else.

I Need   an Expert Advice. ?

VIP Expert


since you exchange BGP between site A and D, you could use an AS prepend, community string, or origin value setup to achieve load balancing and failover. Check this link (go to BGP topology 4) for sample configurations, or post the configs of both site A and site D routers, so we can put the relevant configurations in there...

VIP Expert


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Will the two ISPs have different ASs?  If so, same number of AS hops to D?  If so, you can use the hidden command, bgp bestpath as-path multipath-relax, to allow ECMP.


AS Will be different ... and i think i don't need to do any thing !! in this case Router A  and Router D will Automatically load balance the  traffic and do fail over if one fails .. Right ?


"Fail-over" should be "automatic", using both links, by default, I believe is not "automatic".  I.e. the latter will require some additional configuration.