My PC is connected to the Internet via ADSL. I have a 3G USB dongle, so if I connect both, will the Internet speed be the sum of both the speeds?

If the answer is "no":

  1. Is it possible via alternative methods?

  2. How do I know which connection my software is using? Can I control (by example) if my Firefox will use 3G and FreeDownloadManager will use ADSL?


This is possible through link aggregation or bandwidth bonding, but it's very difficult to achieve with low-end hardware, and also probably expensive.

The DD-WRT router firmware has some support for bonding here:


You would need to buy something like a CradlePoint device to convert your 3G dongle to ethernet, so it could connect to the router as one of the bandwidth sources, and have a DD-WRT compatible router.

Here's a way to do it on a PC with certain Intel network cards, but again, not easy and probably not inexpensive: http://www.intel.com/support/network/sb/cs-009747.htm

UPDATE : Here's a router than can do this out of the box. You'll probably still need a CradlePoint (not cheap) to convert the 3G to ethernet.


  • Did you test that ? Bonding works at layer 2. It is useless unless you control a single router at the end of both links, which isn't the case here. – b0fh Oct 13 '11 at 14:29
  • This router appears to be able to do the job OP is asking for. What do you think? edimax.com/en/… They have models that support up to 8 connections which can be any combination of DSL, Cable Modem, or whatever. – bwall Oct 13 '11 at 14:46
  • Yes but that's no link aggregation, that's SNAT connection balancing; it cannot aggregate speeds for a single TCP connection (for this you still need your own AS or a single remote tunnel endpoint). So that may speed up, say, bittorrent, but not ftp. – b0fh Oct 17 '11 at 11:30
  • You're right, but the OP didn't ask about link aggregation specifically, and his example was about multiple apps using bandwidth at the same time, which fits the connection balancing solution well. – bwall Oct 17 '11 at 16:26

No. Unless you are an Autonomous System with your own address range, you cannot aggregate two lines to double the speed of a single host with a single address.

However, you can have two addresses with two separate lines (that will happen by default). The two interfaces will be exposed as different hosts, so (for instance) each tcp connection will have to use either one or the other. But depending on your operating system, you may be able to set up some rules to make some connections go trough adsl and others trough 3g. You can typically control this by changing the "bind address" of programs that use networking. The way to do it is program-specific.

It is probably more trouble than it is worth, however.

Another possibility, if you control some server outside on a fast connection, would be to put yourself on a VPN, make two separate connections to the vpn hub, and load-balance the routes between the two. Again this is not for the faint of the heart.


Dray Tek has routers affordable for SOHO usage which can do load balancing. See http://www.draytek.com/user/PdInfoDetail.php?Id=35

  • This model is $200+, which is the same price as the CradlePoint device mentioned above. dsl-warehouse.com/… – bwall Oct 13 '11 at 15:03
  • According to the docs the Cradle Point has now WAN input. This means you still have to by another device and put DD-WRT on it and hope you get everything working. The Dry Tek device gives you everything preconfigured in one device. – BetaRide Oct 14 '11 at 6:19

What you are really looking for is for something that implements MPTCP -- Also known as MultiPath TCP.

It seems that there are few routers on the market that do support it at this moment but the situation will change quite fast in the next 12-24 months because the big players already adopted it: Apple (iOS and MacOS), Citrix (NetScaler), F5.

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