When dialup was common, I heard about people connecting two phone lines so it was faster. Could I do that with broadband, the router delivers 12mbps, but I get about 2.5, and I have a extra cable.

The problem is not due to your cable. I guess that your NIC is a 100Mbps one, so a single cable is able of sustaining 100mbps. The problem is the cable between your modem and your Internet provider. This distance is probably several kilometers, which imbeds a slow connexion. As the link until your home is slow, no use to have a faster link inside your home, the problem is outside.

the speeds that the ISP tells you are always theoretical and never seem to be exact. I have DSL 1.5mb and it never gets that fast. There are many different factors that reduce your speed.

I think what tody is trying say is whether he can use 2 cable and achieve 2.5 x 2 = 5mbps.

Well, theoretically you can. I've seen that option for dial-up during the days of win98se. As for cable, it's more or less like load balancing on server system. So, our ordinary OS might not support load balancing, which is a pricy option.

The other issue is like what yordan and jimmy89 mentioned, the speed of the external line. Even if you manage to use load balancing, the bottle neck is still the speed of the line outside your house. Unless they pull another cable all the way from the ISP to your house, else you still get 2.5 x 2 = 2.5

One last thing. With 2 cable connected simultaneously, you need 2 account on your ISP side. I don't many would fork out double of the monthly rental to do that, unless it's for business.

Even if you have a 12mbps connection, this doesn't mean you actualy get 12mbps. First of all, there are a lot of factors that determine the maximum bandwith you get and the most important one is the distance between your house and the closest street cabinet, the further away, the slower the connection gets. If you are too far away to actualy get 12mbps then I'd suggest you to go to your ISP and get a cheaper connection .

Combining two lines is possible, but then you'll have to get yourself a second connection to your ISP and a router that supports load balancing. Running two cables from your router to your computer is useless, the router can only deliver 12mbps so connecting it with a 200mbps line to your computer is serious overkill.

I found multihoming on Wikipedia, it appears to be fairly pointless between dialup and ipv6. Thanks, time to damn the copper in the streets.

I presume you are talking about multiplexing two separate lines from two ISPs.
in that case you either need Hardware that supports load balancing (I think Dlink has a router that does that)
or use two Lan interfaces and find some software that will do the load balancing.

I've always enjoyed the idea of doing this. While it seemed pretty straight forward for dialup modems (I head two phone lines + two isp accounts (or one that you can log into twice heh) + two modems in one computer = 56k*2 speeds) as mentioned it'd be more complex for broadband plus the prices get pretty crazy pretty fast when you start introducing multiple broadband accounts, cards, and special routers into the mix. It's cool in theory but the execution has always, even with dialup, seemed like it may not be worth the effort.

That's odd, I never knew that :S

It might work for DSL connections but it will definitely not work with Cable connections because your house only have 1 cable running through the house from the master cable which is threaded into many other houses in your neighbourhood. Even if you thread an extra cable, that's like cutting another piece of an already very partitioned connection. Thus, the extra effort wouldn't really be worth it since you're still sharing the connection anyways.

xboxrulz