P2P document tree management in a real-time collaborative editing system

Abstract

This paper presents our work in combining peer-to-peer dynamic tree management with hierarchical Operational Transformation (OT) over document trees to achieve low computational and communication costs. We discuss our approach in storing the document tree in a peer-to-peer, distributed manner and maintaining convergence, causality preservation, and intention preservation (CCI) via a peer-to-peer caching system, Because changes are sent to other users within the system only as needed (and cached when possible), our approach minimizes communication costs among multiple readers and writers. Our algorithms balance the traffic and computational load among peers. They ensure that users always have the most current/correct copy of the section(s) of the document which they are viewing. Our approach outperforms existing OT techniques that broadcast messages and compute OT for each operation at all peers. This paper presents our algorithms and simulation results demonstrating the efficiencies and load balancing among peers within the system. © Springer-Verlag Berlin Heidelberg 2007.