This document details how to combine two or more ADSL Internet connections using two
Alcatel USB Speedtouch ADSL modems on one computer running the Linux operating system and using the multilink PPP protocol. As of the beginning of December 2003 this became possible in the UK thanks to ISP Nildram launching a bonded ADSL service. This service uses multilink PPP to combine two or more Nildram ADSL connections to increase bandwidth with very little overhead. Using the Nildram's bonded service and the software as detailed below I have been running a busy web server (this site) at home since the beginning of Jan 2004 on two ADSL lines with a combined upload speed of around 500Kbs. In Feb 2004 I also setup two Nildram bonded ADSL connections where I work as a network admin.
Nildram only officially support this kind of service by the customer using their recommended Cisco routers which cost over £1000. However, I have been able to take advantage of this service using a PC and two Alcatel Speedtouch USB modems. Linux and all the software used in this guide is freely available on the Internet.
http://www.freestuffjunction.co.uk/bondedadsl.shtml