misled by opportunistic routing…

Posted by Jon Crowcroft

so one of the motivations that led me to think about all the Haggle stuff was the Milgram work. THis seemed to imply, as do pandemics, that a series of chance encounters could, over lots of iterations, provide end-to-end communications reliably.

10 years and 100 papers and algorithms later, it isn't looking so rosy - basically, pretty much every clever scheme has a delivery probability that is quite dismal, even if you set the lifetime of packets/bundles to be many days!

of course, we claim there are other reasons to build such a system (we always did - including reality mining style apps and serendipity)...

but the real problem is misunderstanding the result that Milgram got in his six-degrees work, which made use of the postal network - this isn't an opportunistic network - it is an unbelievably reliable aggregator and schedules delivery between pretty much anywhere on the planet mostly on a near daily basis. ANd the cunning people in the postal service historically provide us with a hint on how to apply this in opportunistic networking..

Indeed, if you go back to the distant past - read about Darwin's voyages on the Beagle (or, perhaps more fun, go see the movie Master and Commander) you'll see that any and all ships going around the world were tasked with the duty of delivering and picking up the post. Without deploying a specific scheduled post boat, instead, all boats going the right way were enlisted as the delivery channel.

Thus, instead of contacts between known friends/acquaintances being required in a successful chain, the weak ties are linked across distances by an early internet - but the early internet was, itself, spatially opportunistic (but "packets" were routed over it in aggregate sacks-worth to the right destination sets).

SO we need to build this (actually, back in Intel research cambridge days, I did propose putting a bluetooth device into the lining of all envelopes and postal bags as I guessed that people walking past the post room in each lab would "drop" and "pickup" their post via the bag, and that would achieve this miraculous shortcut that we've been looking for (without admitting defeat and going back to using the interweb:( )

So we need to data-mine people's use of google maps (i.e. equivalent of lifting their Satnav planned routes) and then use those people who've looked up a place (and maybe mentioned it in a tweet or other social media) to act as ferries (as per georgia tech term) Or mules, or, errr, unwitting act as the glue to get us back to the reliable delivery (sure, it still will involve physical travel rather than light-speed photonic networking, but it might get similar delivery properties as the Big-I Internet)

Time to build a simulation and try it based on some trace data....

Building pony express trade routes to strengthen weak ties, and regain the six degrees of separation!!


Tracking shared YouTube links might help improve video delivery performance

Posted by Salvatore Scellato

Even though sharing YouTube links with our friends on Twitter and Facebook might seem a simple and quick action with no consequences, when millions of users are doing so every day it is something much more important. In fact, it becomes possible to track how interest for content items is spreading across social networks to improve performance of the content delivery networks serving those items. This is the problem we have addressed in a recent paper which will appear at the upcoming WWW 2011 conference.