727 research outputs found
Robust streaming in delay tolerant networks
Delay Tolerant Networks (DTN) do not provide any end to end connectivity guarantee. Thus, transporting data over such networks is a tough challenge as most of Internet applications assume a form of persistent end to end connection. While research in DTN has mainly addressed the problem of routing in various mobility contexts with the aim to improve bundle delay delivery and data delivery ratio, little attention has been paid to applications. This paper investigates the support of streaming-like applications over DTN. We identify how DTN characteristics impact on the overall performances of these applications and present Tetrys, a transport layer mechanism, which enables robust streaming over DTN. Tetrys is based on an
on the fly coding mechanism able to ensure full reliability without retransmission and fast in-order bundle delivery in comparison to classical erasure coding schemes. We evaluate our Tetrys prototype on real DTN connectivity traces captured from the Rollerblading tour in Paris. Simulations show that on average, Tetrys clearly outperforms all other reliability schemes in terms of bundles delivery service
Adding Network Coding Capabilities to the WSNet Simulator
This technical report presents the implementation of a Network Coding module
in WSNet - a Wireless Sensor Network simulator. This implementation provides a
generic programming interface to allow an easy specialization of different
coding strategies: random, source/destination-oriented, intra/inter-flow, etc
VECTORS: Video communication through opportunistic relays and scalable video coding
Crowd-sourced video distribution is frequently of interest in the local
vicinity. In this paper, we propose a novel design to transfer such content
over opportunistic networks with adaptive quality encoding to achieve
reasonable delay bounds. The video segments are transmitted between source and
destination in a delay tolerant manner using the Nearby Connections Android
library. This implementation can be applied to multiple domains, including farm
monitoring, wildlife, and environmental tracking, disaster response scenarios,
etc. In this work, we present the design of an opportunistic contact based
system, and we discuss basic results for the trial runs within our institute.Comment: 13 pages, 6 figures, and under 3000 words for submission to the
SoftwareX journa
Evaluating Mobility Pattern Space Routing for DTNs
Because a delay tolerant network (DTN) can often be partitioned, the problem
of routing is very challenging. However, routing benefits considerably if one
can take advantage of knowledge concerning node mobility. This paper addresses
this problem with a generic algorithm based on the use of a high-dimensional
Euclidean space, that we call MobySpace, constructed upon nodes' mobility
patterns. We provide here an analysis and the large scale evaluation of this
routing scheme in the context of ambient networking by replaying real mobility
traces. The specific MobySpace evaluated is based on the frequency of visit of
nodes for each possible location. We show that the MobySpace can achieve good
performance compared to that of the other algorithms we implemented, especially
when we perform routing on the nodes that have a high connection time. We
determine that the degree of homogeneity of mobility patterns of nodes has a
high impact on routing. And finally, we study the ability of nodes to learn
their own mobility patterns.Comment: IEEE INFOCOM 2006 preprin
The fans united will always be connected: building a practical DTN in a football stadium
Football stadia present a difficult environment for the deployment of digital services, due to their architectural design and the capacity problems from the numbers of fans. We present preliminary results from deploying an Android app building an ad hoc network amongst the attendees at matches at Brighton and Hove Albion's AMEX stadium, so as to share the available capacity and supply digital services to season
ticket holders. We describe the protocol, how we engaged our users in service design so that the app was attractive to use and the problems we encountered in using Android
Rethinking reliability for long-delay networks
Delay Tolerant Networking (DTN) is currently an open research area following the interest of space companies in the deployment of Internet protocols for the space Internet. Thus, these last years have seen an increase in the number of DTN protocol proposals such as Saratoga or LTP-T. However, the goal of these protocols are more to send much error-free data during a short contact time rather than operating to a strictly speaking reliable data transfer. Beside this, several research work have proposed efficient acknowledgment schemes based on the SNACK mechanism. However, these acknowledgement strategies are not compliant with the DTN protocol principle. In this paper, we propose a novel reliability mechanism with an implicit acknowledgment strategy that could be used either within these new DTN proposals or in the context of multicast transport protocols. This proposal is based on a new erasure coding concept specifically designed to operate efficient reliable transfer over bi-directional links
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