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I want to use a Cisco 877 router to load balance two WAN connections, each coming in on a different ethernet port. The ISP tells me this isn't possible.

My understanding is that all routers are capable of load balancing, they just must be configured by command line. Is this the case?

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"Load balancing" when it comes to routing is redundant links with something like OSPF cost statements and let your routing protocol take care of it. – dc5553 Apr 27 '12 at 19:43
up vote 2 down vote accepted

Since 870s do support vlans, it would be possible to treat each ethernet port as a single port (and as a wan port).

I see here two solutions for load balancing/sharing:

With both solutions, you will establish two path to a destination device (in the SP network) that will aggregate the flows.

With CEF, two IP (L3) routes are established over the two modems to a router that has your two next-hops on its interfaces.

With MLPPP, two ppp tunnels (L2) are established to a LNS. That would require to terminate the ppp session on the router and not on the modems (also allowing the possibility to load-balance with the onboard xdsl chipset).

Load algorithms are different, and I would advise you to read the documentation of both methods to see which solution fits you best (some kind traffic is much more sensible to out-of-order packets than others).

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The Cisco 877 only has a single WAN port. You would need Router with 2 WAN ports and 2 Termination modems (depending on your connection method) to achieve load balancing. So yes your ISP is right.

But it is best to go with a device that is designed for a load-balancing application.

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That is not the case, especially for consumer/prosumer type routers.

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At that level, something like a link-balancer would be more appropriate. See Elfiq, Peplink, Barracuda, Fortigate...

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Thanks, that's interesting. What's the main difference between a link-balancer and a load-balancer? – chrism2671 Apr 26 '12 at 13:18
They are load balancers... just without the dynamic routing involved with higher-end designs that use BGP, etc. – ewwhite Apr 26 '12 at 13:24

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