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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”.
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 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.
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.)
35 comments on “Can I combine two internet connections to get a faster connection?”
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.
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.
NEVER because they are people…..
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.
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.
IE on one, Firefox on the other: no, no way that I can think of. If there is, it’s most certainly not easy.
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…
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.
I just looked on-line and it seems that there are now load balancing routers that appear affordable
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?
Well I found something affordable on this one:
Prices start at $69,-
I’m getting myself one of these :)
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
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.
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.
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
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?
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.
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?
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?
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.
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
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
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?
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!
Nah it will not work for single file download or playing games online, because you’ll need a single IP address for that.
Hi I have two 3G USB modems from the same carrier and I want to combine them and use them as one so that I double my speed….Is that possible?
That wouldn’t be possible.
Typically, no. You’d have to contact the carrier.
I have written a guide based on the help provided by your article.
It helps you merge your internet connections using both software and hardware based load balancing.
Hey Have you tried iNetFusion. Its a loadbalancer that is supposed to combine multiple internet connections. I have a link for you clusterlinks
I have tried iNetFusion and it did worked to expectations. It does loadbalancing and link aggregation.I can now combine all my available internet connections and download faster,browse quickely.
i love this software.
inetfusion works fine for combining multiple internets. from there website clusterlinks.com it says load balancing is done in inetfusion. tried it and works smoothly without any configurations
Seriously, ive looked for a long long time to find out how to do this for free. but windows 7 automatically combines networks. with 1 network 550kb/s 2 networks. 1.1MB/s so yes windows automatically does this. no need for fancy programs
I think you guys confused this article. The article is asking if two ISP speed can be merge as one like 50+50 then 100 as source. You guys are all saying about redundancy and failover, I didn’t find the answer :(.