Mark M. Hoffman on 14 Sep 2004 04:23:02 -0000

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Re: [PLUG] Bonding GRE tunnels

* Eric Hidle <> [2004-09-13 18:32:26 -0400]:
> There's a subtle difference between load balancing and trunking. In fact, I
> am now having a big discussion on IRC about it :) Load balancing is done
> route by route, so once a route is cached, it will always use one pipe or
> the other, but never both. Trunking is different in that it uses round-robin
> to distribute frames across two interfaces, independent of routing

Right, I meant "bonding" where I wrote "load-balancing" in my first reply.

> information. In my case, routing would be static and determined by the
> underlying GRE tunnels. The bonding would see the two tunnel interfaces and
> round-robin between them.
> I cannot bond the two Ethernets together because they don't go to the same
> place - they are over two different ISPs. The only thing I have that ends up

Ah, OK.

> at the same place is the GRE tunnel. Basically what I need to do is 802.3ab
> at the IP layer instead of the MAC layer. If I did have two connections to
> the same ISP, and their router supported 802.3ab, I could theoretically set
> up, with their cooperation, MAC-layer bonding between my router and theirs,
> and everything would be happy. Unfortunately that is not the case, yet...

I see.  Perhaps some combination of routing based on packet marking
(IP_ROUTE_FWMARK) and maybe a userspace daemon (IP_ROUTE_NF_QUEUE) to
do the marking... ?  I don't think I could code such a thing, assuming
it's even possible.

Anyway, if you figure something out, I'd be interested to see it.


> ----- Original Message ----- 
> From: "Mark M. Hoffman" <>
> To: <>
> Sent: Monday, September 13, 2004 6:25 PM
> Subject: Re: [PLUG] Bonding GRE tunnels
> > Hi Eric:
> >
> > * Eric Hidle <> [2004-09-13 17:53:04 -0400]:
> > > Ok, so everyone knows you can bond two Ethernet interfaces if you want
> extra
> > > bandwidth... here's the bugger - does anyone think it would be possible
> to
> > > bond two GRE tunnels between two locations. I have two places each with
> two
> > > DSL connections and it would be great to be able to bond the GRE tunnels
> > > between them for aggregated bandwidth...
> > >
> > > Any ideas?
> >
> > Heh, I was just reading the Linux Advanced Routing HOWTO (1) the other
> day.  Since
> > the load-balancing stuff works at the device/interface level, why not do
> it the other
> > way around: bond the two together and then tunnel over that?
> >
> > (1) Just in case you haven't seen it:

Mark M. Hoffman

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