Contention-Aware Performance Analysis of Mobility-Assisted Routing Schemes for Delay Tolerant Networks

Delay and disruptive tolerant networks (sometimes also referred to as intermittently connected mobile networks) are networks where most of the time, there does not exist a complete end-to-end path from the source to the destination. Traditional mobile ad hoc routing protocols will fail for these networks because they require the existence of complete end-to-end paths to be able to deliver any data. To overcome this issue, mobility-assisted routing schemes have been proposed that often make a mobile node store and carry a message around, until an appropriate communication opportunity arises. Download Simulator

Most of the mobility-assisted routing schemes for DTNs are based on flooding. We observed that flooding generates a lot of contention in the network, even if it is sparse. And using an analysis which ignores contention to design these schemes leads to erroneous design decisions. We propose a general methodology to derive expressions for expected delay for different mobility-assisted routing schemes with contention. We solve this problem in the following two steps.

1. Study the fundamental mobility properties required to analyze these routing schemes: We identify and derive closed form expressions for the three fundamental mobility properties requires to analyze mobility-assisted routing. The three properties are: (i) The meeting time, (ii) the inter-meeting time, and (iii) the contact duration.
2. Propose a general framework to analyze mobility-assisted routing schemes with contention in the network: We propose a general framework to model contention in DTNs which can be used with any mobility and channel model, and can be used to derive expected delay expressions for any mobility-assisted routing scheme.

1. Apoorva Jindal and Konstantinos Psounis: Contention-Aware Performance Analysis of Mobility-Assisted Routing , to appear in IEEE Transactions on Mobile Computing, January 2009. (CENG-2007-9)
2. Thrasyvoulos Spyropoulos, Apoorva Jindal, and Konstantinos Psounis: An Analytical Study of Fundamental Mobility Properties for Encounter-based Protocols , International Journal of Autonomous and Adaptive Communications Systems, March 2008.