I have a slower "high-speed" Internet connection of 1.5Mbps DSL. I have often wondered if I could get a second line into my house and do a process called link bonding to join the two lines together and increase my bandwidth. There are various routers out there for this, I think I see, but I am still quite new to this.

So how does this work?

I mean, let's say I'm on SSH and connect to some Linux server. Does it connect over both DSL lines during that kind of transaction, or only one?

Or let's say I'm browsing a shopping website with https -- does it join the two lines together for that or only dedicate one of the lines for that?

Or, does it only show improvements if I do activity like load a web page, where responses might come from both ISP lines at once?

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    @pnuts +1 on the edit. You cleared my thoughts up perfectly. – Volomike Jan 13 '13 at 19:21

The above answers seem to relate to load balancing rather than link bonding. Below is a clip (note an appliance is needed at both ends of the connection - will your ISP allow you that?):

SU533357 example:

So I think the answers to your specific questions are: Yes, Yes, No (in order).

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    Having dealt with bonded T1s, this is the most correct answer. Both ends of the physical layer must be connected to equipment that allows the bonding so that the exit traffic is under a single IP address and has a traffic speed of the sum of the number of bonded circuits. – Fiasco Labs Jan 13 '13 at 5:07
  • Thanks for the clarification. I wasn't sure of the terms. So, it appears that if I had an ISP that permitted link bonding, it would work. For now, it appears that I need to isolate family traffic on their own DSL line, and then get two other DSL lines. On the other two lines, I'd route connections to my office servers on one line, and everything else on the second line. – Volomike Jan 13 '13 at 5:45
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    Internet bonding can be done even if the last-mile ISP doesn't permit it. It can be done with tunneling techniques, and doesn't care which ISP the links are from. Here is some info (with a video) from my website: multapplied.net/why-multapplied/how-it-works For a home user, a simple load balancing router is probably a better solution. – Wim Kerkhoff Jan 19 '13 at 21:06

For the type of connection bonding you are talking about, your SSH session will use only 1 line. Depending on the dual-wan router, they will have different types of settings to utilize both links. Line 2 could be used only as a backup. Alternatively, some LAN clients could be assigned Line 1, while other Line 2. Or it could be as simple as round-robin - one request goes over line 1, the other over line 2 and they flip-flop like that. Yet again, least utilized line could have a priority.

When it comes to file transfers, a single stream will utilize only 1 connection. If you want to speed up your downloads, you'd need use some download manager or similar tool that can have multiple files or parts of a file downloading at once.

When it comes to HTTPS.. I'm not sure..I suspect it might be problematic if you establish an HTTPS session with one connection and suddenly request comes in over another connection. I imagine routers won't do connection load-balancing for things that require persistent sessions.


Because of how TCP/IP work, it is very likely that each "line" would have it's own IP address. Most systems that require a direct connection (i.e. SSH) would only bound to one of those lines. In the case of Bit Torrent or Web Pages, there should be ways to have multiple connections, and I feel those would be where you would benefit from this.

Not all websites are made the same though, but I also believe that with HTTPS, most, if not all, sites would require you to contact them from ONE IP address during your transaction

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