Buffer management in delay tolerant networks

Abstract

The highly successful architecture and protocols of today's Internet may operate poorly in environments characterized by very long delay paths and frequent network partitions. The need to establish communication to run applications in such extreme environments has never been more required. With the massive evolution in wireless devices, many new networks have emerged. Delay-Tolerant Network (DTN) is a new network that models systems that are characterized by intermittent connectivity and frequent partitioning. In order to cope with these long disconnections, messages must be stored for long periods of time. This means that inter­ mediate nodes require sufficient buffer space to store all the messages that are waiting for future communication opportunities and the routing strategies need to consider the available buffer space when making decisions. Thus, an effective buffer management is required to manage the transmitting and dropping messages in the network. This thesis presents various mechanisms of buffer management. In first contribution, POMDP framework is used to find an efficient strategy that node can follow when its buffer is full in order to store a new message. In the second one, a mechanism of congestion control in PRoPHET protocol is proposed to eliminate insignificant messages so as to improve the network performance. Finally, in the third contribution, Stackelberg game is used to incite caching in DTNs in the case of selfish nodes. The main objectives of buffer management are (a) to delete the redundant information in the system, (b) to formulate a reasonable queue strategy, and (c) to control congestion. Simulation results are presented for each contribution, showing the difference between the proposed mechanisms and those already found in literature.