[aklug] Re: Bonding multiple network connections

On Wed, 20 Jan 2010, Scott A. Johnson wrote:

> Hello all -
>
> Looking for anyone with experience bonding network connections, or who
> has even researched the concept. Would love to discuss your
> experiences and insights. I have run a load-balancing setup for a
> while with two separate modems/connections via a layer 3 router
> appliance. This works for opening up multiple transfer sessions
> aggregating your bandwidth in a roundabout way, but I had a thought
> the other day that perhaps if I looked at renting a dedicated host in
> a datacenter somewhere, and establishing separate VPN connections over
> both links from my network to the rented server, by controlling the
> software at both ends perhaps I could truly bond the connection and be
> able to increase my bandwidth over a single TCP session.
>
> Back in the late 90's/early 2000's some specific ISPs offered to bond
> connections via "MLPPP", which again required specific
> software/hardware at both your end and the ISPs hence the limited
> rollout, but the support for MLPPP doesn't seem to be what I would
> call solid these days due to the lack of demand (from what I can
> tell). This is the path I'm currently exploring due to my previous
> thought that if I controlled the software at both ends of the VPN
> tunnel I might be able to actually achieve a bonded connection.
> Thought I see if any fellow LUG members had looked into this before
> (or actually done it) before I go about reinventing the wheel.

The core bonding support in Linux (via the bonding module) won't give you
more bandwidth for a single session. Even if you could do true 802.3ad
modes (which you can't with your setup) it doesn't work that way. Once a
session is opened it becomes associated with a specific physical interface
until that link goes down. Your only choice is whether you want that
association to be made on a L2, L2+L3, etc., basis. I do this kind of
bonding on a regular basis.

MLPPP, as I recall, only worked with multiple connections from a single
provider, and they had to support it on their end. Which meant that it
applied at L2, not L3, which is what you're proposing here. I've never
used it, so maybe I'm wrong. Hopefully someone else can chime in.

         --Arthur Corliss
           Live Free or Die
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Received on Wed Jan 20 13:58:59 2010