Semantic and Locality Aware Consistency for Mobile Cooperative Editing

Abstract

This paper presents CoopSLA (Cooperative Semantic Locality Awareness), a consistency model for cooperative editing applications running in resource-constrained mobile devices. In CoopSLA, updates to different parts of the document have different priorities, depending on the relative interest of the user in the region where the update is performed; updates that are considered relevant to the user are propagated frequently, while less important ones are postponed. As a result, the system makes a more intelligent usage of the network resources, since 1) fewer accesses to the network are issued, 2) bandwidth savings are obtained by merging the delayed updates, and 3) reduced bandwidth available is used more efficiently by propagating more relevant updates sooner. These properties are of vital importance in the mobile environments we are addressing, in which devices have limited bandwidth and battery power. We have implemented a collaborative version of Tex editor TexMaker using the CoopSLA approach. We present evaluation results that support our claim that CoopSLA is very effective in reducing the overhead of replica synchronization without imposing limitations to application models.