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Load balancing between 2 ISP's

Level 1
Level 1

We are currently in the process of trying to determine the best way to load-balance internet traffic between 2 ISP links (300mg each) that we are going to Peer with via BGP.  Our plan is to receive all routes from both providers and then load balance between them (if possible) 

My question is if we only take in partial routes from both ISP's and a defualt route from both, then redistribute into OSPF on the my FW, will OSPF load-balance between the ISP's when the default route is used? I'm thinking that it will, but i'm not sure if there is any configuration needed to tell it to do this.  I would prefer NOT to take in the whole routing table from the ISP's and use the default routes they are advertising.

Any help would be appreciated !!

Thanks !

1 Reply 1

Joseph W. Doherty
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Hall of Fame


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I would consider the "best" way to balance egress traffic would be using PfR, this assuming your equipment supports it.

From what you describe, 2nd best (for a single edge device) would be to direct all traffic to it (single default route to it) and allow it to use BGP ECMP.  The latter requires BGP routing be configured to support two paths, maximum-paths 2, and usage of the hidden command bgp bestpath as-path multipath-relax.