Can I combine two internet connections to get a faster connection?

Everyone wants a faster internet connection. I'm frequently asked if it's possible to combine two or more connections for speed. The answer is yes ... but.

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Can I merge two internet connections so that I have doubled bandwidth? I have a DSL connection as well as a separate EVDO connection. I want to know if it is possible to merge the internet connections so that the bandwidth speed would be added to each other, resulting in increased bandwidth.

Because this article was originally written a few years ago, the answer has actually changed from “mostly no” to “mostly yes, with a caveat”.

There’s hardware now available – not even all that expensive – that will allow you to connect two internet connections to your local area network.

But … there might be a catch.

Depending on what it is you’re hoping to accomplish, you may be disappointed.


What you’re looking for is often referred to as a “dual WAN” router. WAN is short for Wide Area Network (as opposed to your LAN or Local Area Network) and typically refers to the internet.

Dual WAN Router

Dual WAN Router

Two connections to the internet.

Two should be better than one, right?

Mostly, the answer is yes, although there’s one scenario where the answer is “not so much”.

Redundancy

One common use for dual-WAN routers is to provide redundancy. When two internet connections are used, particularly if they are from different providers, either one can go down and the other continues to work.

In other words, to the computers on the LAN-side of the router, the internet will just keep on working. Perhaps more slowly, but it’ll still be there.

In fact, some dual WAN routers can be configured to use only one of the two connections until there is a problem, and then “fail over” to begin using the other, backup connection until the primary is repaired. This may be useful if the cost of the second connection is based on data transferred, or if the second connection is significantly slower than the primary.

Load Leveling

Load leveling is a technique used by the router to distribute your internet traffic as equally as it can across both connections.

One perhaps over-simplified approach is to simply alternate connections between the two: each time a computer on your LAN requests a data connection to an internet resource that data connection is made using one of the two available internet connections. The next request uses the other. That way, by simply alternating back-and-forth which internet connection is used to fulfill connection requests, the load is distributed roughly equally across the two internet connections.

Typically, that means things happen faster.

For example, a web page that has two pictures on it might download one picture on one of the internet connections and the other picture on the other. That way, the two can be downloaded in parallel – twice as fast as if they both had to be downloaded using the same connection.

Unfortunately, load leveling cannot make all types of downloads faster.

Faster downloads? Maybe, maybe not

A logical connection from a computer to a server can happen on only one physical connection.

If your computer requests two pictures on a web page, that’s actually three logical connections: one for the web page itself and one for each picture. As we saw, a dual WAN router may elect to distribute those across either of the physical internet connections that it has.

But what if you’re downloading only one thing, one BIG thing.

That can only happen over one physical internet connection, and you’ll be limited in speed to that of the single connection.

Other internet activity may be shuffled off to the other internet connection, so your download may be faster than if you were using only a single connection, but it’ll never be faster than the speed of a single connection.

Spreading out the download for speed

It’s possible that some so-called “download accelerators” may use multiple connections to download a single file, which in turn may allow a dual WAN router to use both internet connections to speed it up.

But there’s another case where downloads can be significantly impacted by having multiple internet connections.

Bittorrent

By design, the bittorrent protocol uses multiple internet connections to download (and upload) files. A properly configured dual WAN router could significantly improve bittorrent performance by spreading the load over both
internet connections.

(This is an update to an article originally published January 10, 2007.)

There are 41 comments:

  1. Chris Buechler Reply

    There aren’t any extremely simple ways to do this, but pfSense (www.pfsense.org), a free open source firewall, does have multi-WAN capabilities so if you have an old PC and a few network cards, you can accomplish this entirely with free software. You can use policy-based routing, to say send HTTP out one connection, mail out another connection, P2P traffic to one connection, etc. and can also do load balancing.

    Not exactly a breeze for a novice to setup, but not insurmountable either.

  2. K T Yeo Reply

    If u hv an old junk Pentium 2 computer, U can put in a free linux OS and configure it for Dual WAN, Dual NIC, QOS service. visit http://www.brazilfw.com.br. Donate if u find it useful. Free Load Balancer and loads more feture for hobbyist.

  3. Chris Reply

    A bit off topic I know, but I noticed you said “My DSL is limited to 768k down and 128k up. Nowadays that’s slow..” I live in Australia, and while speeds greater then that are avaliable in my area, your connection is considered very good. My connection of 512K/128K is considered unecessarly fast, especially when a lot of people are using dial up (56K). Here most people pray for speeds greater then the 128K broadband average. Why arn’t people satisfied with connections 10 times faster then what was avaliable 5 years ago? What has tecnology done to civilisation? A bit over the top I know, but I think you know what I’m getting at.

    When will people be satisified with what they have.

  4. Jonwolf Reply

    If you had 2 connection, can you assign each each software or program for each of the connection? for example, firefox browser using connection 1 and IE using connection 2, instead of combining the two.

  5. Leo Notenboom Reply

    Chris: I can answer that last one: never! :-)

    Seriously, though, I think we all (or at least ‘us geeks’) expand our usage to exceed our capacity, no matter what we have. And the same is true of available content and applications.

    5 years ago things like youtube and google video didn’t exist. iTunes wasn’t in the picture. And I wasn’t trying to remote-manage my wife’s business across the net. Now speeds are making such things possible. I can do all of that today with my 768/128, it’s true. But I’d do them faster, and start doing some new things, with a faster connection.

  6. Leo Notenboom Reply

    IE on one, Firefox on the other: no, no way that I can think of. If there is, it’s most certainly not easy.

  7. Thor Johnson Reply

    Well… it can be done and others have mentioned the load-balancing firewall. The missing bit is being able to adjust the routing tables on the “far side” of the connection… it is possible (and is provided for), but most ISP’s won’t let you mess with them because if you make a mistake, you can wind up with things like “all internet traffic bound for Italy goes through my house” (urg!), so most ISP’s won’t let you mess with the routing tables.

    You might be able to explain what you want and get them to put the rules in though…

  8. Another Chris Reply

    I’d just like to point out that not everyone in Australia considers 512/128 adequate. I’m currently on a 1500/256 and a bit annoyed that I can’t get 12000/1000 because my phone line does not run direct to an exchange – it’s on a subexchange. The 1500 down is fine, it’s the 256up that’s too slow.

  9. Umut KIRGOZ Reply

    Cannot it be success with a software, I have been asking as a newbie in network field…

  10. Harri Gee Reply

    I just looked on-line and it seems that there are now load balancing routers that appear affordable

  11. Daryl Reply

    I was thinking of buying two services DSL which offers me 1.5 up and 1.5 down and Cable which offers me 8 MB down and 785k up. Could I use a load blancer and make all my up traffc go up the DSL and down traffic to go though the cable?

  12. chr|z m'sia Reply

    Well 1st, i ahve a router isnt there a port just like the phone lines connector (yes the one witha box shape)come with not 1 but 2 ports for line and then pass trough to 1 line as thats the purpose of the connector? if u get me!
    or why cant i just remove the cover of the connector attach another line (screw the colour cables together and fix it back making it werk as one. its not bout power but data right? am i nuts? would i blew up something? nid this for my company..hit me back somebody!
    Am i missing something?

  13. Shaun McDonald Reply

    I’m living in Edinburgh, Scotland. I’m currently moving from 2048/256 cable internet to potentially 24Mb down/1.3Mb up through ADSL2+. Here it is getting to the stage that dial up is more expensive than broadband, and having dialup is frowned upon due to the high availability of broadband. I know someone, who’s parents are so old fashioned, they won’t upgrade from Dial up, even so broadband is cheaper.

    In my transition of providers, I’ve considered having a dual internet connection for a month, just for the novelty.

  14. kosmin Reply

    Hi, here in Romania, the GSM provider Orange-Ro, has o good offer of internet on mobile phone. I test the 3G conection and is very good speed in contrast with GPRS. What I whant to know if can I make a bridge conection betwen two mobile phones both with 3G conection ? Or something to work together ?

    And then can I use multiple internet conection in the same time with more the two mobile phones conected to the same PC ?
    Best Regards
    Kosmin D.

  15. Ghost Rida Reply

    Hi there. I have 2 usb huawei modems and two internet accounts. Can I use both at the same time on the same pc.Can i use 1 or one download and the other for another download, what i mean is that can i download two files at the same speed.

  16. Mubi Reply

    Hello,
    if i am correct u want to merge the two dsl modems into 1 then there is a solution available now.
    The great WOWWEB PRO software i am using it on windows xp as a service …

    some features of it includes..

    WOOWEB-PRO is a router and firewall software providing a solution at the corporate level for outgoing and incoming Internet access – See WOOWEB V2 for home use. It runs in any PC on Windows 2000/XP/Vista and supports the most popular Internet connection types such as routers, cable modems, ADSL modems (PPPoE, USB PPPoA), analog or ISDN modems.

    When installed on the computer that drives the modem(s), it behaves as a multiple-port router and enables all networked computers to access the Internet simultaneously, whatever their type and operating system.

    The WOOWEB-PRO firewall provides a strong protection against Internet attacks. It can be configured and it gives information details about the intrusion attempts. There is no need for an extra networked firewall.

    WOOWEB-PRO accepts incoming connections. However, the access to your servers is tightly controlled by the rules you set up. These rules permit to forward the remote Internet users to the right servers, only to the right applications, at no risk for other computers. In addition, all accesses are recorded in log files.

    WOOWEB-PRO V4 can manage up to 16 Internet connections in dedicated, balancing, or fail over mode. The global bandwidth can be distributed evenly to all users, or shared out according to configurable per-user rules, guaranteeing a minimum or a maximum percentage of the global throughput.

  17. Adam Reply

    yes you can
    i have resently but a device calld MAHA Integrator and it dos the job
    i connected 4 internet lines to it and after that have don a speed test on my combined lines and it shoes 4 times as moch as a single line in both upload and download
    if anyone needs one you can call and get one from them
    the phone number i have behind the device is (888) 462-0476 and 001 (916) 335-1063
    thay both say customer service but i think you shuld be able to get a sales departments number from ther to

  18. GM Reply

    well i red all the comments very usefull, one more thing can we use one connection as download and the other one as upload , if its bossible let me know

  19. Srevo Reply

    There are a few devices out there. The best I have found (using now) is an Xtreme Router from http://www.workman-engineering.com. router cost around $700 but will not only combine wired connections it does Wireless too! Works great I log into like a normal router with an IP and it is very easy to use.

  20. AJ Reply

    I just setup one – purchased vpn linksys router RV042 – ordered two dsl lines from AT&T and setup the whole thing in under 30 minutes, Check out the router, made by cisco and marketed under linksys piad $150.00 US Dollars. Easy.

  21. ifrit723 Reply

    u call that internet speed slow.. i have a 78k down SPEED!!! ITS HORRIBLE…. and my sister keeps hogging it making my speed like dial up

  22. Dan the man Reply

    Ive just recently purchased a ethernet card for $4.00 my dell desktop it allready had 1 but want to see what the difference would be and i love it it seams to run 75% faster than it was but whatever it was having 2 Ethernet ports connected to my router it handle streaming videos better and multitasking online like yahoo messenger used to give me hell when surfing the web now no problem im downloading at 3.0 m bps no more buffer online movies but it requires a hub im not a technician its better than before idk if this will work for people with lower speeds of internet dsl

  23. Nikita Mundada Reply

    Hi,
    I am a final year Computer Engineering student and I want to know that can we download multiple parts of the same file from say a website by two different connections
    if that website is aware that more than a single connection is in use
    at the client end???
    Please reply soon

  24. yes you can Reply

    There is a simple program that does this.Its was running in windows xp , i dont have it anymore and i guess me and you have to search many forums to find it :) , it could pair two lan or a lan and a virtual usb lan , a wifi with a lan … keep on looking it.

  25. Jawad Hussain Reply

    I didnt get the answer of the question rather completely i would say…
    my question if i use a simple Dlink switch and put two DSL cables in it and take the LAN wire to my pc…will anything bad happen or not?

    Either it won’t work at all, or you won’t get double the speed. If either of those scenarios qualifies as “bad”, then yes, something bad will happen.

    Leo
    17-Dec-2010

  26. Eddie Reply

    Is there any updated information for this question. It looks as though it was originally posted 3yrs ago.

  27. Ameer Reply

    Well, I’m establishing a network where they’re using 2 internet connections and a local server machine for the application that they need for office services.
    I’ve configured two of the connections and they are working fine, as a matter of fact i’m using three different IP addresses.
    why so i do this ?? If any of the connections is down another will take over and server will not stop responding.
    i just wanna say that you don’t need any kind of balancing device or something all you need is just a good mind.

  28. Julie Watts Reply

    I have purchased an Edimax 150Mbps wireless USB adapter to increase the strenght of my wifi connection but now my computer is showing two connections. One with Local and internet and the Edimax adapter with local only. Can I merge these two connections to get a better signal. If I do what are the consequences? Is it possible that I would lose my internet connection to become local only?

  29. Karan bhatia Reply

    Come on this is2011 now, I’m using windows 7 on a wifi laptop. There MUST be a way to combine two wifi connections, or at least 1 wifi and the other ether net, or 1 wifi and the other usb tethered mobile (using either a3G connection or a diff wifi than the one already connected on the laptop). Anyone?

  30. Dashrender Reply

    Karan,
    Sure there are ways to combine, just as this newlyl updated article mentions.
    But, if you are on ethernet already, even at 100 Megs, the chances are you can’t come close to that connection speed on your ISP connection, even if you have two ISP connections. If somehow you are, then you should upgrade your home network to gigabit networking and surely your home network will have more bandwidth inside your home than you are getting from your ISP.

  31. Michael Reply

    I have use two dual-wan routers.

    The first, somewhat old now, was a Netgear FVS336G and I would not recommend it. I always uses one net connection and only uses the second when it detects a failure. Also, how it detects a failure is very limited.

    The other one I have used is the bottom-of-line Peplink Balance which sells for about $300. Much better. It uses both WAN connections concurrently and offers five different load balancing schemes (higher end models offer 7 schemes). In addition, it is more flexible in its definition of a failure of a WAN connection. And, it supports wireless connections too, but I have not tried that feature. For details on their lineup see
    http://www.peplink.com/balance/tech-spec/

  32. Scott Reply

    How about using two Wi-Fi connections simultaneously on a laptop or desktop with one source from the integrated Wi-Fi card and the other from a USB attached device using the same or different IPs? Will they automatically combine to broaden the bandwidth or will one remain dormant? I seem to recall the task manager showing two simultaneous trackers in XP now I am using 7.

  33. Yogesh Roy Reply

    In simple terms it is as easy as switching on the two connections as long as you have the two connections on two separate adapters i.e. two separate nic cards or one Ethernet and one wireless or two different wireless. you only have to make sure that you dont get the same lan ip on both the intefaces but this is mostly taken care of by the OS.but you can’t control the connection to use for a particular task and it is the connection with a higher ip address that gets the preference for connection or you can use ForceBindIP

  34. Achal Saraiya Reply

    What about multipart upload, I use Amazon S3 for file uploading and sharing, I have two connections one wifi and other 3G USB Stick, is there any software/drivers that use alternate connection to send requests for windows as well as linux?

  35. Matthew Reply

    Hi, thanks so much for the article! It is still useful even many years after published. I use online streaming through Twitch.tv and this makes a huge difference on my ping when I play MMO games!

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