Recovery support for Internet-based real-time collaborative editing systems

For reliability purpose, recovery support must be employed in the Internet-based real-time collaborative editing systems. This paper describes a recovery scheme in which each site maintains a local document state (LDS) that is generated periodically. Thus, if a failure occurs in the Internet links or at the site, the site can rejoin the collaborative editing system by loading the LDS instead of obtaining the state from the remote sites. This is a much faster process than the traditional approach of recovery by regaining the system´s document state from other peer sites. Consistency between the local state and remote state during the recovery procedure is maintained in the recovery algorithm for which the proof is provided. The performance of our recovery scheme is assessed by generating the elapsed time between a failed site joining and leaving the systems