Message fragmentation in opportunistic DTNs

Abstract

Delay-tolerant networking is used for communication in challenged environments such as MANETs, in which links are unstable and end-to-end paths between communicating nodes may not exist. Messages may be significantly larger than packets in IP networks. Large messages lead to longer transfer times rendering it more likely that a link breaks in the middle of a message transfer. This motivates investigating how to support partial message transfers through fragmentation. In this paper, we formulate fragmentation independent of routing algorithms, introduce several fragmentation strategies, and evaluate these by simulations to derive recommendations for using fragmentation in DTNs.

Best-effort authentication for opportunistic networks

“…Those improvements, are due to better utilization of contact opportunities, and mirror the results in [2]. In coarse-grained resource management, nodes group themselves into domains and give priority to other domain members.…”

“…Our investigations focus on the second method due to its general applicability and exhibited performance gains in [2]. In particular, we focus on a variant of reactive fragmentation where messages are fragmented at senderdefined boundaries.…”

“…The probability of successfully delivering a forged fragment depends on p and i, where i is the number of hops on the path to the destination. If we assume, for simplicity, that all intermediaries independently verify fragments with the same probability 2 1−p, then the probability of a successful attack is p i . Harvesting many signed Bloom filters can lead to an offline pre-image attack.…”

“…Research has shown that message fragmentation can improve delivery ratios in opportunistic networks through better utilization of available contact opportunities [2]. Fragmentation in the presence of resource hogs implies the need for publicly verifiable fragment authentication.…”

Contribution to the improvement of communication services in nanosatellite constellations using delay and disruption tolerant networking based architectures

“…Also, if the fragments of the proactive fragmentation are well adjusted to the contact opportunity, this may perform slightly better than reactive fragmentation. The effect of the fragmentation on the message delivery success have been studied on [29] showing that the fragmentation could increase overall connectivity but it is prerequisite to know a message size and contact duration distribution. Also in [30] several fragmentation algorithms have been studied for different land scenarios.…”