A Message Repository for Delay-tolerant Networks
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Elektroniikan, tietoliikenteen ja automaation tiedekunta |
Master's thesis
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Authors
Date
2010
Department
Major/Subject
Tietoverkkotekniikka
Mcode
S-38
Degree programme
Language
en
Pages
[7] + 71
Series
Abstract
Internet technology, as well as other networking technologies, is running based on some assumptions, such as the existence of an end-to-end path between source and destination, low data loss rate, utilizing a packet-switching mechanism in communication and end devices supporting the TCP/IP protocol suite. However, these assumptions may not hold in the emerging challenged networks such as mobile ad-hoc networks. Thus, new solutions are needed to address the arising problem in challenged environments. Delay-tolerant Networking (DTN) approach is one robust way to enable communication in the environments with high delay and frequent disruption. Due to the challenged environments, DTN nodes have limited contact opportunities to forward messages. Therefore, the message delivery ratio of DTN networks is always lower compared to that of the traditional Internet. With the intention of enhancing the network performance and increasing the message delivery ratio, we deploy a set of infrastructure nodes, which are called message repositories (MRs), into DTN networks. MRs are the normal DTN nodes with infrastructure connectivity and supporting specific message exchange mechanism. When a mobile user connects to a MR, they are able to retrieve messages which they are not hold from each other following a specific message exchange procedure. We evaluate the performance of the MR scheme by means of simulation. We expect to figure out in which cases, and by how much the MR increases the message delivery rate and shortens the message delivery delay in DTN networks. We unitize an urban scenario with multiple environmental variables for our simulation. The most important environmental variables include underlying DTN routing protocols, the number of MRs and MRCs, node buffer size, etc. Furthermore, we compare the performance of multiple message exchange mechanisms of MR scheme in our simulation.Description
Supervisor
Ott, JörgKeywords
Delay-tolerant Networking (DTN), Message Repositories (MRs), Message Repository Clients (MRCs), simulations, routing models, mobility models