How to combine internet connections?

December 12, 2005 12:21 PM

Is there a way to combine two broadband internet connections? For the time being, I have two ISPs, one cable and the other DSL. They both have their own modems. If possible, I'd like to use both at once and double my throughput.
posted by iconjack to computers & internet (15 comments total)

Not. Your two services use separate IP spaces with different router hops to the same desitinations. For example, when you browse to Google using your cable modem, the traffic traverses different equipment once it leaved your house than when you go to the same site using DSL. There's no way to recombine the different bits in a way that is transparent to your computer.
posted by pmbuko at 12:27 PM on December 12, 2005

oops: not possible.
posted by pmbuko at 12:27 PM on December 12, 2005

It could theoretically be done by assigning alternating requests to the two connections. This will get you a rough approximation of doubled throughput. However, things like FTP that only use a single connection won't see a benefit unless you use a program that downloads using multiple connections.
posted by kindall at 12:31 PM on December 12, 2005

Would be useful for usenet.
posted by meta87 at 12:32 PM on December 12, 2005

This article talks about how to do basically what kindall suggests above, albeit in Linux. It's pretty technical, though. Anything I could have said is said above or in this link.
posted by cacophony at 12:34 PM on December 12, 2005

I can think of some ways to do if you had a high-bandwidth server somewhere else on the internet that you'd connect to through your two connections, but otherwise, no. The internet doesn't work that way.
posted by cillit bang at 12:36 PM on December 12, 2005

You can certainly load balance two connections. The cheapest way I can think of is to get a bsd box with three NIC cards. A little info to get you started here.
posted by skallas at 12:37 PM on December 12, 2005

This would make the most sense for something like torrents where there are many connections getting small amounts of the file.
posted by abcde at 12:52 PM on December 12, 2005

It's possible. It's called Multihoming. Hooking your computer up to two separate connections would require two network cards, or Ethernet to one and Wifi to the other, but it could be done. OS X supports multihoming out of the box. I'd be astonished if Linux did not also. Can't speak for Windows.
posted by adamrice at 12:54 PM on December 12, 2005

adamrice, what OS X supports out of the box is called Ethernet Link Aggregation (ELA), which is not multihoming. Both links must be on the same network connected to the same switch, and that switch must support ELA (802.3ad). It's meant to increase the LAN bandwidth available to the computer, but had no real effect on WAN/internet traffic.
posted by pmbuko at 1:10 PM on December 12, 2005

load balance

load balancing would be for serving requests. what i think is being asked about is connection teaming.

diagrams referring to another vendor make it more clear just how much hardware is involved.
posted by 3.2.3 at 1:40 PM on December 12, 2005

Hmm, pmbuko, what's all this about then>?

Apparently I was wrong about needing two physical interfaces for this to work, though.
posted by adamrice at 2:04 PM on December 12, 2005

Yes, this can be done. No, it's not that easy. cacophony linked to a decent article.

Or, you could see if the isps will do BGP for you.

OR, check out this FAQ on the subject.
posted by drstein at 2:30 PM on December 12, 2005

We use this dual homed router at work. It load balances our DSL and cable services. We mainly want it to keep the internet connection going if one service goes offline. It probably works better for a group of users to be split between the two services, instead of one person trying for faster speeds. About $160.00
posted by jjj606 at 3:01 PM on December 12, 2005

what's all this about then?

That article says nothing about using two networks simultaneously. Yes, you can configure a single interface to use more than one network, but you cannot tell it to use more than one network simultanously.
posted by pmbuko at 8:09 AM on December 13, 2005