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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Router with 2 (or more) interfaces in same network
On Tue, Nov 11, 2003 at 09:55:34AM -0500, Leo Bicknell wrote: > In a message written on Tue, Nov 11, 2003 at 08:35:34AM +0000, Sugar, Sylvia wrote: > > I am curious to know if its possible to have a router with its two interfaces, say configured as, > > 1.1.1.1/16 and 1.1.1.2/16. Theoretically, i see nothing which can stop a router from doing this. > > Cisco's don't let you do this. I have always considered that broken, > although I'm sure Cisco thinks it's a feature. I'm not sure how Cisco is wrong on this one. If you want 2 router interfaces to have the same route and you actually want both of them to work, it means at the very least you must have a non point-to-point medium, such as Ethernet. In this case, the correct configuration would be a bridge-group and IRB, creating a virtual routed interface with 2 physical ports for bridging. > Other routers (of note FreeBSD boxes) do this just fine. In almost all > cases I've seen it done it was for more bandwidth to the box (typically > inbound only, because there are no good tools on Unix boxes to split the > traffic between the outgoing interfaces). I love FreeBSD, but it's routing code is probably the thing you least want to look to for examples on how things should be. BTW there is a netgraph module for L2 hash-based load balancing (aka etherchannel without the PAgP/LACP), but yeah the lack of ECMP and a reasonable switching method to support it falls into the category of the previous sentence. :) -- Richard A Steenbergen <[email protected]> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)
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