A Reliable and Efficient Encounter-Based Routing Framework for Delay/Disruption Tolerant Networks

Abstract

Abstract-This article addresses Delay/Disruption Tolerant Networking (DTN) routing under a highly dynamic scenario, envisioned for communication in Vehicular Sensor Networks (VSNs) suffering from intermittent connection. Here, we focus on the design of a high level routing framework, rather than the dedicated encounter prediction. Based on an analyzed utility metric to predict nodal encounter, our proposed routing framework considers the following three cases: 1) Messages are efficiently replicated to a better qualified candidate node, based on the analysed utility metric related to destination. 2) Messages are conditionally replicated if the node with a better utility metric has not been met. 3) Messages are probabilistically replicated if the information in relation to destination is unavailable in the worst case. With this framework in mind, we propose two routing schemes covering two major technique branches in literature, namely Encounter-Based Replication Routing (EBRR) and Encounter-Based Spraying Routing (EBSR). Results under the scenario applicable to VSNs show that, in addition to achieving high delivery ratio for reliability, our schemes are more efficient in terms of a lower overhead ratio. Our core investigation indicates that apart from what information to use for encounter prediction, how to deliver messages based on the given utility metric is also important.

A Geographic Multicopy Routing Scheme for DTNs With Heterogeneous Mobility

“…Considering the heterogeneous nodal mobility, replicating message copies [22] to a better qualified (L − 1) nodes has been investigated. To expedite delivery via topological utility metric, EBSR [9] further relays (without generating additional copies) a message copy with (C M = 1) copy ticket. Based on geographic utility metric and underlying map topology, GeoSpray [23] (via underlying map topology) calculates the Nearest Point (NP) to destination to guide message relay.…”

“…Note that GeoSpray limits the number of copies a message can be replicated. Besides, EBRR [9] and EBSR [9] are topological routing schemes proposed for VSNs comprising heterogeneous 7 Compared with data message, the ACK message is with quite small size that only contains nodal ID (like a "string"). Therefore, the bandwidth and buffer space consumed by ACK can be ignored.…”

“…The motivation behind this is to enable at least one of these message copies can be delivered successfully before expiration deadline. As already investigated in [9], limiting the number of message copies (relayed by the source and possibly other nodes receiving a 1 In sparse VANETs or VSNs, network nodes are normally connected in a sparse mode and also opportunistically encounter each other. As such, the network would experience frequent network disconnection in rural locations with sparsely populated roads, and also during non-busy hours such as late night.…”

Toward Efficient Electric-Vehicle Charging Using VANET-Based Information Dissemination

“…• Referring to previous analysis on opportunistic encounter [24], the time until EV encounters any one of M buses, is given by…”

Highly-Efficient Bulk Data Transfer for Structured Dissemination in Wireless Embedded Network Systems

“…These protocols employ three-way handshake and NACKs to ensure reliability [21,22,23], and divide code images into pages to enable pipelining. Deluge is the default dissemination protocol in TinyOS [24].…”