3 research outputs found

    Spray Router with Node Location Dependent Remaining-TTL Message Scheduling in DTNs

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    Delay and disruption tolerant networks (DTNs) adopt the store-carry-and-forward paradigm. Each node stores messages in a buffer storage and waits for either an appropriate forwarding opportunity or the message\u27s expiration time, i.e., its time-to-live (TTL). There are two key issues that influence the performance of DTN routing: the forwarding policy that determines whether a message should be forwarded to an encountered node, and the buffer management policy that determines which message should be sent from the queue (i.e., message scheduling) and which message should be dropped when the buffer storage is full. This paper proposes a DTN routing protocol, called spray-and hop-distance-based with remaining-TTL consideration (SNHD-TTL) which integrates three features: (1) binary spray; (2) hop-distance-based forwarding; and (3) node location dependent remaining-TTL message scheduling. The aim is to better deliver messages which are highly congested especially in the “island scenario.” We evaluate it by simulation-based comparison with other popular protocols, namely Epidemic as a baseline and PRoPHETv2 that performs well according to our previous study. Our simulation results show that SNHD-TTL is able to outperform other routing protocols, significantly reduce overhead, and at the same time, increase the total size of delivered messages.Special Issue of Applications and the Internet in Conjunction with Main Topics of COMPSAC 201

    Towards Practical Store-Carry-Forward Networking: Examples and Issues

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    In the evolution of wireless networks such as wireless sensor networks, mobile ad-hoc networks, and delay/disruption tolerant networks, the Store-Carry-Forward (SCF) message relaying paradigm has been commonly featured and studied with much attention. SCF networking is essential for offsetting the deficiencies of intermittent and range limited communication environments because it allows moving wireless communication nodes to act as “mobile relay nodes”. Such relay nodes can store/carry/process messages, wait for a better opportunity for transmission, and finally forward the messages to other nodes. This paper starts with a short overview of SCF routing and then examines two SCF networking scenarios. The first one deals with large content delivery across multiple islands using existing infrastructural transportation networks (e.g., cars and ferries) in which mobility is uncontrollable from an SCF viewpoint. Simulations show how a simple coding technique can improve flooding-based SCF. The other scenario looks at a prototype system of unmanned aerial vehicle (UAV) for high-quality video surveillance from the sky in which mobility is partially controllable from an SCF viewpoint. Three requisite techniques in this scenario are highlighted - fast link setup, millimeter wave communications, and use of multiple links. Through these examples, we discuss the benefits and issues of the practical use of SCF networking-based systems

    Nullspace-based stopping conditions for network-coded transmissions in DTNs

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