Total order in opportunistic networks

• Published in: Concurrency and computation
• Main Authors: Costea, Mihail, Ciobanu, Rado-Ioan, Marin, Radu-Corneliu, Dobre, Ciprian, Mavromoustakis, Constandinos X, Xhafa, Fatos, Mastorakis, George
• Format: Journal Article
• Language: English
• Published: Concurrency and computation 14.12.2016
• Subjects: Algorismes distribuïts; Algoritmos distribuidos; consistencia; consistency; consistència; delay tolerant; Distributed algorithms; opportunistic networks; orden total; ordre total; redes oportunistas; redes tolerantes al retardo; total order; xarxes oportunistes; xarxes tolerants al retard
• ISSN: 1532-0626
• DOI: 10.1002/cpe.4056

Opportunistic network applications are usually assumed to work only with unordered immutable messages, like photos, videos, or music files, while applications that depend on ordered or mutable messages, like chat or shared contents editing applications, are ignored. In this paper, we examine how total ordering can be achieved in an opportunistic network. By leveraging on existing dissemination and causal order algorithms, we propose a commutative replicated data type algorithm on the basis of Logoot for achieving total order without using tombstones in opportunistic networks where message delivery is not guaranteed by the routing layer. Our algorithm is designed to use the nature of the opportunistic network to reduce the metadata size compared to the original Logoot, and even to achieve in some cases higher hit rates compared to the dissemination algorithms when no order is enforced. Finally, we present the results of the experiments for the new algorithm by using an opportunistic network emulator, mobility traces, and Wikipedia pages.