Impact of content storage and retrieval mechanisms on the performance of vehicular delay-tolerant networks

“Copyright © [2010] IEEE. Reprinted from 18th International Conference on Software, Telecommunications and Computer Networks (SoftCOM 2010). ISBN: 978-1-4244-8663-2 . This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”Vehicular Delay-Tolerant Networking (VDTN) is a new disruptive network architecture based on the concept of delay tolerant networks (DTNs). VDTNs handle non-real time applications using vehicles to carry messages on their buffers, relaying them only when a proper contact opportunity occurs. Therefore, the network performance is directly affected by the storage capacity and message retrieving of intermediate nodes. This paper proposes a suitable content storage and retrieval (CSR) mechanism for VDTN networks. This CSR solution adds additional information on control labels of the setup message associated to the corresponding data bundle (aggregated traffic) that defines and applies caching and forwarding restrictions on network traffic (data bundles). Furthermore, this work presents a performance analysis and evaluation of CSR mechanisms over a VDTN application scenario, using a VDTN testbed. This work presents the comparison of the network behavior and performance using two DTN routing protocols, Epidemic and Spray and Wait, with and without CSR mechanisms. The results show that CSR mechanisms improve the performance of VDTN networks significantly.Part of this work has been supported by the Instituto de Telecomunicações, Next Generation Networks and Applications Group (NetGNA), Portugal in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence from the Seventh Framework Programme of EU, in the framework of the Specific Joint Research Project VDTN

Storage Usage of Custody Transfer in Delay Tolerant Networks with Intermittent Connectivity

Delay Tolerant Networks (DTNs) operate in a environment characterized by intermittently connected links and long, variable latency. End-to-end reliability schemes, such as TCP, perform poorly, or not at all, in this environment. Source node storage becomes a constrained resource when intermittent links have long downtimes or latency to receive acknowledgement from the destination is long. To alleviate this constraint, custody transfer is a proposed DTN reliability scheme using hop-by-hop reliability to enhance end-to-end reliability. A simulation study of storage usage is presented in this paper comparing endto-end reliability and custody transfer with three different intermittent link connectivity schedules. The results presented show significantly lower storage usage when custody transfer is used as opposed to end-to-end reliability in intermittently connected networks for all schedules considered