DISTRIBUTED SOURCE-DESTINATION SYNCHRONIZATION USING INBAND CLOCK DISTRIBUTION

This paper presents a new distributed methodology for source-destinati on synchronization for interactive teleconferencing, The method is bas ed on a reference clock, which is synthesized, from a distributed glob al clock, The global clock is generated by periodically exchanging inb and synchronization signals with neighboring nodes. The timing jitter achieved with this method can be arbitrarily close to the jitter obtai ned by the centralized synchronous methods which usually use an out-of -band, hard-wired reference clock. The global clock synchronization al gorithm, used in this work, guarantees frequency locking of all the ne twork nodes to the slowest clock in the system, As a result, the slowe st clock can be used as an implicit reference clock for source-destina tion synchronization protocols, such as synchronous frequency encoding technique (SFET) and synchronous residual time stamp (SRTS). This inb and synchronization method does not require the explicit knowledge of which clock is actually the slowest in the system. Therefore, if the s lowest clock fails, then another clock on a different node will be the slowest, and the nodes will use it as a reference clock for the sourc e-destination synchronization protocol, The existing out-of-band refer ence clock techniques do not have this strong fault tolerant property.