Combine two connections (Wifi or ethernet) for a single torrent download. Listen to streaming audio and download side by side. Routing through multiple uplinks.

Hi, So my friend was out on weekend, and I had two spare/live connections (256kbps) at my disposal. My objective was to download a single file(using torrents) at 512kbps.

Here’s what I finally achieved.

Updated – Azureus supports multiple interfaces. Check out the end of post.

1. Both cards @ 256Kbps

and Azureus dowloading at 512Kbps

Convinced ??

OK, so one of my connections is through ethernet(wired) and other one is through wifi.

All of below is tested on Ubuntu but theoretically should be doable on Windows as well.

Separate Connections using VirtualBox – Host on wireless, virtual machine on wired network

Its no big deal using those two connections on same PC achievable through virtualization. I use VirtualBox to virtualize Windows XP on Ubuntu. You will have to use “host networking” to achieve this. Let me give a brief summary of how I do this.

Install bridge-tools, sudo apt-get install bridge-utils uml-utilities

Here’s how I create a virtual bridge and add eth0 in promiscuous mode to it.

sudo tunctl -t tap0 -u kx
sudo chmod 666 /dev/net/tun
sudo ifconfig eth0 0.0.0.0 promisc
sudo ifconfig tap0 0.0.0.0 promisc
sudo brctl addbr br0
sudo brctl addif br0 eth0
sudo brctl addif br0 tap0
sudo dhclient br0

Now create a new network adapter, attached to host interface and chose interface name tap0. If you have DHCP running on router both host machine and virtual machine will get DHCP address from router or you can configure static IPs.

Restore network as:

sudo ifconfig tap0 -promisc
sudo ifconfig br0 down
sudo brctl delif br0 eth0
sudo brctl delif br0 tap0
sudo brctl delbr br0
sudo tunctl -d tap0
sudo ifconfig eth0 -promisc
sudo dhclient eth0
sudo ifconfig eth0 down
sudo ifconfig eth0 up

Its OK, we can download one file in Virtual Machine and another on host machine @ 256Kbps each. But this is not what we want. We want to download *that single movie* in half the time at 512K

Combining connections on Single Host

Make sure you have removed any bridges or virtual devices from previous section. Just reboot to be sure.

Start configuration: Just make sure both interfaces are up and have IPs. I use WICD to manage my networks on Ubuntu. So quicky “ifconfig” and see if you have 2 IPs. If not, up that interface, “ifconfig eth0 up” and probably get an ip, “sudo dhclient eth0”. I’ll leave this to you guys assuming you’ll be able to do it.

Ok now, Print your initial routing table, “route -e”

Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 eth1
10.1.1.0 * 255.255.255.0 U 0 0 0 eth0
default 192.168.1.1 0.0.0.0 UG 0 0 0 eth1
default 10.1.1.1 0.0.0.0 UG 0 0 0 eth0

Now I don’t want 2 default routes so I delete one.

sudo route del default gw 192.168.1.1 eth1

Now all of my traffic goest through 10.1.1.1 which is my wired network. So, grab a torrent client and load that movie. Set max connections per torrent to a figure like 300. Let it download for a few minutes. When it has connected to lets say 50 peers. Browse to peers tab. And just note the relative categories of IPs of peers.

For e.g. In my case almost half were from range 50.X.X.X to 100.X.X.X and rest were from other space. Now all of these connections are going through default gateway from our routing table. All we want to do is add some alternate route for this address space.

Okie Dokie. Stop the download. Here’s the script file I created for the same purpose.

if [ $# -lt 4 ]
then
echo "Error - Range and interface missing $#"
echo "Syntax : $0 start_range stop_range gateway_address interface"
echo "E.g. ./add_range 50 55 192.168.1.1 eth1"
exit 1
fi
for (( i = $1 ; i <= $2; i++ ))
do
sudo route add -net $i.0.0.0 netmask 255.0.0.0 gw $3 $4
done

Copy the above code and save it in a .sh file. For e.g. I run it as

./add_range 50 100 192.168.1.1 eth1

That’s it. Run start the torrent again. Al peers in IP range 50.X.X.X to 100.X.X.X would go through wireless interface and all others through default gateway i.e. wired interface.

Just make sure that the default gateway corresponds to interface. For e.g. in my case 192.168.1.1 -> eth1 and 10.1.1.1 -> eth0

Similarly you can delete some ip ranges.

if [ $# -lt 4 ]
then
echo "Error - Range and interface missing $#"
echo "Syntax : $0 start_range stop_range gateway_address interface"
echo "E.g. ./delete_range 50 55 192.168.1.1 eth1"
exit 1
fi
for (( i = $1 ; i <= $2; i++ ))
do
sudo route del -net $i.0.0.0 netmask 255.0.0.0 gw $3 $4
done

You can keep on dynamically adding routes to balance no of connections over two interfaces. You are in control

Streaming music and Downloads

For e.g. while listening to lastFM, normally I find my music streamed from 87.X.X.X, So I added this dedicatedly to wired interface and make my wireless interface, the default gateway. So now I can browse, download stuff without breaking my music.

It shouldn’t be too hard to dynamically add these routes based on total number of connections across each interface. All that script would do is add entire ip range (lets say 50.X.X.X to 190.X.X.X) to gateways alternately based on total number of connections across each interface.

Here is a nice article which lets you manage multiple links in a more standard way and lets you do load balancing as well.

Azureus supports multiple links. 

As commented by surgio in comments, azureus does support dynamic routing across multiple interfaces as indicated in his screenshots. Please have a look at his screenshots in the comments section for the same. Here’s the setting if someone is interested.

Have a nice time downloading.

Again, in case any doubts ask questions.