Multiple Redundancy Constants with Trickle

TL;DR

This paper develops an analytical model for the Trickle algorithm in wireless sensor networks, addressing multiple redundancy constants and node synchronization issues, and proposes a heuristic to improve message fairness among nodes.

Contribution

It introduces a new analytical model for Trickle with multiple redundancy constants and proposes a heuristic for fair message dissemination based on node neighbors.

Findings

Redundancy constants vary with node degree to improve fairness.

The heuristic reduces message transmission unfairness among nodes.

Model validation confirms effectiveness of the proposed approach.

Abstract

Wireless sensor network protocols very often use the Trickle algorithm to govern information dissemination. For example, the widely used IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) uses Trickle to emit control packets. We derive an analytical model of Trickle to take into account multiple redundancy constants and the common lack of synchronization among nodes. Moreover, we demonstrate message count unfairness when Trickle uses a unique global redundancy constant because nodes with less neighbors transmit more often. Consequently, we propose a heuristic algorithm that calculates a redundancy constant for each node as a function of its number of neighbors. Our calculated redundancy constants reduce unfairness among nodes by distributing more equally the number of transmitted messages in the network. Our analytical model is validated by emulations of constrained devices running the Contiki Operating System and its IPv6 networking stack. Furthermore, results very well corroborate the heuristic algorithm improvements.