Causal and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e703" altimg="si3.svg"><mml:mi>Δ</mml:mi></mml:math>-causal broadcast in opportunistic networks

Causal broadcast is a fundamental communication abstraction for many distributed applications. Several implementations of this have been proposed over the last decades traditional networks, that is, networks assume existence continuous bi-directional end-to-end path between any pair nodes. Opportunistic constitute kind in which assumption cannot be made, though, so implementation causal such must addressed differently. This paper presents two algorithms based on barriers can ensure causally-ordered delivery messages an opportunistic network, considering both cases where propagate network without or with bounded lifetime. The latter case especially interesting run long time, population nodes changes continuously.