[Nrg-l] NRG Presentation: 10/06/2005

Vijay Erramilli evijay at cs.bu.edu
Mon Oct 3 12:16:47 EDT 2005

Hi All,

After much arm-wringing, Vijay has agreed to give a presentation titled 

"Pocket Switched Networks: Is there a packet in your pocket, or are you 
just pleased to see me?"

The presentation is based on the paper:

Pocket Switched Networks: Real-world mobility and its consequences for 
opportunistic Forwarding

Augustin Chaintreau,Pan Hui, Jon Crowcroft, Christophe Diot, Richard Gass 
and James Scott 
Intel Research Cambridge
University of Cambridge

Where: The Grad Lounge
When: 11 am, Thursday 6th October, 2005

And no, the title of the presentation is not Vijay's but is attributed to 
Christophe Diot.


Opportunistic networks make use of human mobility and local forwarding in order to distribute data. 
Information can be stored and passed, taking advantage of the device mobility, or forwarded over a 
wireless link when an appropriate contact is met. Such networks fall into the fields of mobile ad-hoc 
networking and delay-tolerant networking. In order to evaluate forwarding algorithms for these networks, 
accurate data is needed on the intermittency of connections. In this paper, the inter-contact time between 
two transmission opportunities is observed empirically using four distinct sets of data, two having been 
specifically collected for this work, and two provided by other research groups. We discover that the 
distribution of inter-contact time follows an approximate power law over a large time range in all data sets. 
This observation is at odds with the exponential decay expected by many currently used mobility models. We 
demonstrate that opportunistic transmission schemes designed around these current models have poor performance under 
approximate power-law conditions, but could be significantly improved by using limited redundant transmissions. 


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