Using redundancy to cope with failures in a delay tolerant network

Abstract

We consider the problem of routing in a delay tolerant network (DTN) in the presence of path failures. Previous work on DTN routing has focused on using precisely known network dynamics, which does not account for message losses due to link failures, buffer overruns, path selection errors, unscheduled delays, or other problems. We show how to split, replicate, and erasure code message fragments over multiple delivery paths to optimize the probability of successful message delivery. We provide a formulation of this problem and solve it for two cases: a 0/1 (Bernoulli) path delivery model where messages are either fully lost or delivered, and a Gaussian path delivery model where only a fraction of a message may be delivered. Ideas from the modern portfolio theory literature are borrowed to solve the underlying optimization problem. Our approach is directly relevant to solving similar problems that arise in replica placement in distributed file systems and virtual node placement in DHTs. In three different simulated DTN scenarios covering a wide range of applications, we show the effectiveness of our approach in handling failures.

LOFT: A Latency-Oriented Fault Tolerant Transport Protocol for Wireless Sensor-Actuator Networks

“…The simulation settings are mainly drawn from [5], which are summarized in Table II. We consider a loss model in which packet loss occurs because of poor channel quality [13]. Every link is characterized by a failure probability, which is the probability that a packet is dropped during the transmission to the next hop.…”

“…Ganesan et al [12] described the use of multipath routing for energy-efficient recovery from node failures in wireless sensor networks, which presents and evaluates the classical node-disjoint multipath and the braided multipath designs. S. Jain et al [13] considered the problem of routing in a delay tolerant network in the presence of path failures. It improves the probability of successful packet delivery by applying a combination of erasure coding and data replication.…”

Erasure-coding based utility routing in multi-hop wireless networks

“…The network coding methods use replication (redundancy) and send identical copies of a message simultaneously over multiple paths to mitigate the effects of a single path failure [20]. Jain et al [21] and Wang et al [22] applied erasure coding to delay tolerant networks (DTNs). Cui et al [23] proposed a jointly opportunistic source coding and opportunistic routing (OSCOR) protocol for correlated data gathering in wireless sensor networks.…”

How Mobility Models Affect the Design of Network Coding Schemes for Disruption Tolerant Networks

“…Previous studies have proposed to use erasure coding to deal with network disruptions in DTNs [5], [6]. It has been shown that network coding [7] can improve the throughput in wireless communication.…”