Date: Thu, 03 May 2001 17:36:10 -0700 (PDT) From: Ted Mittelstaedt <tedm@toybox.placo.com> To: Wai Chan <waichan@hpu.edu> Cc: freebsd-net@FreeBSD.ORG, freebsd-questions@FreeBSD.ORG Subject: Re: outgoing traffic load balancing with multiple ISP Message-ID: <988936570.3af1f97a333bf@mail.freebsd-corp-net-guide.com> In-Reply-To: <LNEJKGADPHKMLOFLNLFLCEEIFAAA.waichan@hpu.edu> References: <LNEJKGADPHKMLOFLNLFLCEEIFAAA.waichan@hpu.edu>
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Quoting Wai Chan <waichan@hpu.edu>: > I have two ISPs (two different serial links to my router). I want 50% > of > all outgoing traffic go through ISP 1 with ISP 1 provided IP address as > source address, and the other 50% of all outgoing traffic go through ISP > 2 > with ISP 2 provided IP address as source address. > Is there any reason you can't just build a second router and plug the serial link from the second ISP into it, then take the inside interfaces of both routers and plug them into the same hub, and run multiple address ranges on the hub? Then put half of your systems on one IP range and half of them on the other. I realize that your not going to divide the traffic up 50% this way but the problem is (and was just thashed over in this list less than a week ago) that ISP #1 cannot route IP numbers supplied by ISP #2, and ISP #2 cannot route IP numbers supplied by ISP #1, unless you have been given entire netblocks by both ISP's and are running BGP with both and are advertising those netblocks. Even then, load balancing is a tricky problem because it's almost entirely dependent on the destination IP numbers that traffic from your servers is going to. If you were multihomed with your own AS in the manner you would find that in most cases, traffic is going to favor one interface over the other. Generally, if your careful in picking your feeds it's not going to be worse than 60/40 one way or the other, but if you do something like using a very well connected network for one link and a poorly connected network for the other, it can be as bad as 90/10. Have you investigated bonding or multilink with one of your ISP's? There's also a way to multiplex T1's together that some ISP's support. Ted Mittelstaedt tedm@toybox.placo.com Author of: The FreeBSD Corporate Networker's Guide Book website: http://www.freebsd-corp-net-guide.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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