It was not originally clear that Greg controlled both ends of the FTP connection. If that were the case, then you could use each dsl modem connection separately, and use some sort of VPN or tunneling software to create two separate (virtual) "trunks" between the two servers. Then bond those trunks together like regular interfaces. OpenVPN would be a good cross platform candidate for VPN. Whichever bonding mode you choose, you should make sure it can handle link failure "gracefully".
On Fri, May 9, 2008 at 10:15 AM, Ed Allen era@jimani.com wrote:
FTP being based on UDP is connectionless so no worries about TCP connections being trashed by confusion over IP addresses.
Cough Cough http://www.faqs.org/rfcs/rfc959.html Cough...
The BONDING section of the article pointed to, by Johnathan Hutchins I think, specifically mentions that it works with DSL.
UDP is inherently unreliable so the receiving software must deal with packets arriving from multiple routers, intermediate hosts, with differing amounts of delay so FTP software reassembles out of order packets coming from different addresses constantly.
A TCP stack does that too. http://www.faqs.org/rfcs/rfc793.html (Page 4, Section: Reliability)
So bonding should help, but I would like to ask if these pages could be generated as "one page" files so that individual pages could be mirrored to a high speed connected server while the next one is being assembled ? That way you can combine all the pages if needed for the final push at deadline across the high speed link and spread the use of your limited upload speed out over time when it would otherwise go unused.
-- Ed Allen