View Full Version : [all variants] Aggregate multiple ISPs

August 12th, 2009, 03:20 PM

I want to aggregate (not load-balance) multiples (in my case 3) xDSL lines (all differents ISPs) on my linux router.

PC Linux Router (in our office) with 4 NICs cards :
- eth0 (LAN : connected to a simple switch
- eth1 connected to ISP1 (15 Mbps)
- eth2 connected to ISP2 (15 Mbps)
- eth3 connected to ISP3 (30 Mbps)

eth1, eth2 and eth3 have their own IP & Gateway; all different.

I know that I can load-balance using iproute or iptables, but this is not what I'm looking for.
I also know that I can use MLPPP, but the ISPs need to support it, so it's not a solution for me.

What I'm looking for is aggregate the links of our 3 ISPs (15+15+30= 60 Mbps !!) through a server in a datacenter (with a big Internet pipe : >100 Mbps). The way to achieve this would be to :

Make 3 VPN connections (1 for each ISP) from our Linux router to our Datacenter' Server
Bond these 3 VPN connection using "Linux Ethernet Bonding" (ifenslave package), resulting in a new bond0 interface
Configure our linux router to use bond0 to access Internet (create a new route ?)
On the Datacenter's server, configure iptables (MASQUERADING ?) in order to route all traffic coming from the VPNs connections to Internet

The theory seems to be good, but I don't have enough Linux expertise to achieve this, does anyone have already set-up something like this ?
Any idea/tutorial would be appreciated.

Right now, I'm stuck with vtun (http://vtun.sourceforge.net/) and creating a VPN for each iface. I can create 3 VPN easily (tap0, tap1, tap2), but I can't figure out how to force tap0 to use eth0, tap1 to use eth1, and tap2 to use eth2. Because, all 3 tunnels passes through the default route on eth1 (ISP1), instead of allocating 1 tunnel to 1 iface (ISP).

References :

ADSL Bonding – Howto and Review (http://www.automatedhome.co.uk/Internet/ADSL-Bonding-How-To-and-Review.html)
Multiple Connections to the Internet (http://linux-ip.net/html/adv-multi-internet.html)
Routing for multiple uplinks/providers (http://lartc.org/howto/lartc.rpdb.multiple-links.html)
Somebody with a similar problem on a mailing-list, but no answer (http://unix.derkeiler.com/Newsgroups/comp.unix.bsd.freebsd.misc/2005-12/msg00619.html)

September 12th, 2009, 01:21 PM

I've spent upwards of 10 hours trying to get an answer to this exact problem. Apparently people on the internet think aggregation = LOAD BALANCE LOLOLOL.

Somebody help.

September 12th, 2009, 03:27 PM

I've spent upwards of 10 hours trying to get an answer to this exact problem. Apparently people on the internet think aggregation = LOAD BALANCE LOLOLOL.

Somebody help.
No, people think what you're trying to do is COMPLICATED, sounds brilliant but poor Ubuntu users wouldn't necessarily know (I speak for myself of course only). Have you tried other networking forums?

Sorry for not much help but let us know how you're getting on, sounds interesting. Lucky is the person that has a 60Mbps (eventually) internet connection.

September 16th, 2009, 10:52 AM
Hi Ellixis, Having had a quick look at this, the biggest problem i can see is IP space from different ISP's. Aggregating those 3 VPNs into some bond0 interface will necessitate the use of a public address from one of your ISP's - of which access into that one ISP cloud is then rate limited - I assume they are all different providers?

November 10th, 2009, 11:24 AM
have you found a solution ?
i wanna do the same here :)

December 7th, 2009, 02:32 PM
It's easy enough to have multiple default routes, one needs to use iproute2 to set up multiple routing tables. The linux advanced routing howto documents it reasonably, but can be tricky if you don't have a good understanding of TCP/IP.

I can assist further on a paid basis if you want to head down that path (email me or reply here)


December 19th, 2009, 03:49 AM
Once more, I come back do drop off a quick update - and brevity increases with each response ;-0.

German Thread mentioning a howto which prescribes in detail a 2.6 vtun bonding solution (he uses 6 dsl lines) :


Actual step-by-step tutorial in German :


Google Translated to US English :


Enjoy. As requested earlier - please post feedback after having a pop (I will so the same when I have time).

February 20th, 2010, 09:05 PM
Howdy all,
I've been looking into this and similar problems for a while. To be clear I want to restate what the "this" is:

1) Multiple low cost ISPs providing access to a single facility
2) The ISPs come with their own network address space and don't interoperate directly.
3) None of the ISPs will support BGP.
4) I want to aggregate all of the bandwidth
5) I want to perform transparent failover when possible if any of the ISPs stop routing for some reason.

Here's what I found:
The best open source treatment of the problem I had seen was actually done with freeBSD 4.x. Nothing says you couldn't use similar software on Ubuntu to duplicate the results. Take a look:


This was the most comprehensive solution for the open source community I could find. I did find a lot of "Hey check out my hack!" stuff that was half fast treatment of this very complex problem.

I also found several hardware, proprietary, solutions for dealing with this problem. This is useful for a couple of reasons:
1) It tells me there's a market for this
2) It gives me an understanding of how they are treating the problem so that parallel solutions can be sought in the linux world.
3) It lets me know the ceiling of money (read effort) involved in addressing the challange. (IE: if I was only willing to spend X $ I wouldn't have to spend Y hours). Anyway, take a look at these:

The most promising one is this: http://www.internetloadbalancers.com/
Click on network load balancing on the left.
Barracuda had a similar but seemingly less capable product.


Just my research so far- LS

Tags: bandwidth aggregation, multiple ISPs, linux, aggregate bandwidth, no BGP

May 3rd, 2010, 09:45 PM
There is a product that will BOND multiple ISP's and it dosn't require any co-opperation from the ISP's. It can do it with the same ISP or different ISP's.
:arrow: www.frdmnetworks.com (http://www.frdmnetworks.com) is the site. I spoke to a guy there called Jared and he was full of information and had a great knowledge of the ability to bond and how it compared to a load balancer. I had a great discussion with him about this.:popcorn:

I would sugest contacting them.

They are internationaly around the globe.:KS

May 18th, 2010, 02:53 PM
hey ppl. i just stumbled across your discussion.

i have achieved this with vtun bonded vpn's using the opensource appliance zeroshell.

i have detailed my approach in a howto here:

www.ieee754.org (http://www.ieee754.org)

naturally its point to point - but it address' the OP's needs if i have understood correctly.

i have over 10 links aggregated using this technique. for optimal performance all links need to exhibit similar latency and contention - otherwise, in my experience, a significant and adverse affect is imposed on performance.



May 3rd, 2011, 10:00 PM
Indeed it is possible to bond ISP connections without requiring any equipment on the ISP side \\:D/

The trick is to use a broadband bonding router. I heard of frdmnetworks.com, another one is mushroomnetworks.com - from their websites it sounds like they implement bonding at a higher layer than Phy or Mac and therefore no need for the ISP =D>