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Suppose I have 2 ISP(Broadband) with 2 routers(DSL). Now I have 1 switch of say 4 ports.

So can I connect to both the ISP using 1 PC to get my speed up.

  • ISP A gives me a speed of 2Mbps
  • And ISP B gives me a speed of 1Mbps

Now I have only 1 PC and also have a switch. Can I connect to both the ISP's at a single time to get a total speed of 3Mbps.

Or will it show me some error- I think it will say that default gateway can't be same. Don't know if it is possible or not.

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migrated from Dec 25 '09 at 17:52

This question came from our site for professional and enthusiast programmers.

The easiest way to configure this would be to use a Multi-WAN router such as the Linksys RV042.

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i have already suggested a dual WAN router in my answer, if you wish to second an recommendation you should upvote it instead of posting a similar answer, if you wish to contribute additional information you can leave a comment (when you have 2000 'karma points' you will be able edit existing answers). – Molly7244 Dec 25 '09 at 18:54
@Molly: I know the rules, I've been on SO since beta. =) your answer didn't have a link to such a router when I posted mine, and to be honest, I didn't read the quoted text to the end before posting my answer. then you updated your answer, and I read the full text, but decided to keep my answer anyway since I mentioned a different router. – Can Berk Güder Dec 26 '09 at 20:24

Technically: yes

In practice, it's an exotic and expensive configuration.

You can put more than one address on an interface or use more than one interface and be multihomed.

However, this is much more likely to be effective for a big server cluster in a data center.

Expensive routers capable of running routing protocols will be needed and then it still would not help you with a single given TCP connection.

If you try this as a single user of two retail ISPs, then you will have two different IP addresses, so incoming traffic will use the one you made the outbound connection on, and it's unlikely that any equipment you have can be configured with more than one gateway.

A large site with a /24 or shorter prefix and their own ASN can actually announce a single IP address over multiple networks, but that won't work without being further upstream than a retail ISP line.

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A simple switch / network hub will not suffice ...

So you have two independent legal Broadband accounts (can be two DSL two Cable or one of each.)

There are two terms that might be associated with using two independent Internet connections.

  1. Combining Bandwidth.

  2. Load Balancing two connections.

Let assume that you have two 3Mb/sec. connections each capable to download at 300KB/sec.

With Combined Bandwidth you should be able to download one file at 600KB/sec.

With Load Balancing one single file will not exceed download speed of 300KB/sec. However you can download 2 files at 300KB/sec. or 4 files at 150KB/sec. etc.

Unfortunately Combining Bandwidth can not be done without the ISP providing such a specific service.

Computers are Not mind readers. If the two connections are not synchronized at the source your computer would know how to combine it to a coherent page.

Any if and but about it is just Wishful thinking.

The price of such a service (if available) is usually much more expensive than upgrading your connection from the basic service to a faster business or corporate service.

If you do have two independent services you can achieve Load Balancing by using a Dual WAN Router.

This type of Cable/DSL Routers have two WAN connections for two Broadband Modems and they would mange the Internet traffic to the LAN to be used in the most efficient way.

The ZyXEL P-663H-51 is souch a router.

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