28 Jul 09 Multithreaded TCP Proxy Tunnel

Sometime back I posted a guide in the HOWTO section on load balancing across multiple ISP connections. This is great in certain instances but certainly doesn’t replace line bonding.

With torrent traffic for example, it works great. The various peer connections should be established equally over the various ISPs and you really can utilize the bandwidth of multiple uplinks. A single connection however can only ever be established over one ISP, and this is the biggest limitation for the following reasons:

1) A single HTTP, POP3, SMTP, FTP, etc connection for example will only be established over one ISP whilst the other remains idle.
2) Incoming connections can only come in over one ISP depending on the IP accessed.

I’m sure there are further situations that might suffer limitations due to the setup.

The best way around this that i could think of was creating a multithreaded tcp proxy. The software consists of a proxy client and proxy server. I would run the proxy client on the local end, and the server on some remote machine. The client and the server will create a number of TCP connections between them which should hopefully be split across the ISPs equally, and reassembled by the proxy server at the other end.

The limitations of this though are that the entire session will be limited to the speed of the slowest link, and any of the links failing will cause the tunnel to become corrupted and fail.

C code and an update to come shortly.

Tags: isps, multiple uplinks, Multithreaded TCP Proxy Tunnel, split access

14 Sep 08 Extending tc and iproute2. Linux routing split access multiple uplinks multiple isps iptables masquerading

It’s been a while since I last posted here, so I thought I’d post a followup article to http://www.adamsinfo.com/bandwith-limiting-with-linux-tc-and-iproute2/ which focused on bandwidth limiting in a datacenter environment using tc and iproute2.

I’ve taken the same script but tweaked IPs and bandwith values into my office. Previously I was on a 24mbit down 2.5mbit up DSL connection courtesy of www.bethere.co.uk The office is only about 800m from the closest exchange which is quite nice – I generally find I get 18+mbit down and 1.5+mbit up. Not only great bandwidth, but latency is also very small and responsiveness is great, especially as a regular [constant] SSH use. Recently, despite having no business justification whatsoever, I ordered the same again for the same office. This one clocks in at about 19mbit up and 1.7mbit down – even better! Some ISPs support line bonding – I dont believe that many in the UK do, and seeing as at the time of writing, bethere were the only ISP to support anywhere close to 24mbit, I wasn’t going to try and find another.
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Tags: Extending tc and iproute2, faster torrent, iproute2, iptables, Linux routing, masquerading, multiple isps, multiple uplinks, Routerboard load balancing, split access, tc, torrent