Performance implications of fragmentation mechanisms on Vehicular Delay-Tolerant Networks

Vehicular Delay-Tolerant Network (VDTN) is a new disruptive network architecture where vehicles act as the communication infrastructure, furnishing low-cost asynchronous opportunistic communications, variable delays and bandwidth limitations defining a non-TCP/IP (Transmission Control Protocol/Internet Protocol) network. A VDTN assumes asynchronous, bundle-oriented communication, and a store-carry-and-forward routing paradigm. VDTNs should make the best use of the tight resources available in the network. In order to optimize the data exchanged among nodes at contact opportunities, increasing the bundle delivery and improving the overall network performance, fragmentation mechanisms are used. This paper presents several fragmentation techniques (proactive, source, reactive, and toilet paper) for VDTNs and evaluates their performance through a laboratory testbed. It was shown that both reactive fragmentation approaches (reactive and toilet paper) perform slightly better than proactive fragmentation approaches (proactive and source) and non-fragmentation approaches.