Opportunistic DTN routing with window-aware adaptive replication

Abstract

This paper presents ORWAR, a resource-efficient protocol for opportunistic routing in delay-tolerant networks. Our approach exploits the context of mobile nodes (speed, direction of movement and radio range) to estimate the size of a contact window. This knowledge is exploited to make better forwarding decisions and to minimize the probability of partially transmitted messages. As well as optimizing the use of bandwidth during overloads it helps to reduce energy consumption since partially transmitted messages are useless and waste transmission power. Another feature of the algorithm is the use of a differentiation mechanism based on message utility. This allows allocating more resources for high utility messages. More precisely, messages are replicated in the order of highest utility first, and removed from the buffers in the reverse order. To illustrate the benefit of such a scheme the global accumulated utility is used as a system-wide performance metric. Simulations illustrate the benefit of our model and show that ORWAR provides lower overhead and higher delivery rate, as well as higher accumulated utility compared to a number of well-known algorithms (including Maxprop and SprayAndWait).

Adding Redundancy to Replication in Window-aware Delay-tolerant Routing

“…This paper is an extension of a preliminary work on ORWAR [8] presented earlier. The work has been extended in three directions: (1) Extensive simulation of all routing schemes in different scenarios allowing to determine a confidence interval, (2) Extension of the framework by adding fragmentation/redundancy which shows substantial gains in delivery ratios on top of the base protocol, (3) Improvement of the delivery ratio by pulling the dropped fragments when an infrastructure network can be used for the "last few".…”

Fair content dissemination in participatory DTNs

“…In RAPID [45], a utility-based approach, is introduced which can optimize delay-related metrics (e.g., average delay, missed deadline), by treating routing as a resource allocation problem; the uniqueness of the protocol lies in taking constraints of both bandwidth and storage into account, in order to determine how packets should be replicated in the system. ORWAR [46] is another approach that also reasons in terms of utility, but focusing on network-wide optimization, in order to minimise the probability of partially transmitted messages.…”

Routing Approaches in Delay Tolerant Networks: A Survey

“…Opportunistic Routing with Window Aware Replication (ORWAR) proposed by Sandulescu et al [49] also exploited the knowledge of the context. The contexts are speed, direction of movement and radio range.…”

“…In [55], these replicas were handed over to the first encountered nodes. But in [49] distribution was based on the evaluation of node's available window.…”