An efficient synchronization method for dual bus networks

The problem of the loss of synchronization in high-speed dual-bus MANs or LANs (metropolitan or local area networks) is considered, and an efficient method to recover alignment is proposed. The proposed mechanism provides for use of a particular bit pattern, called a synchronization pattern, which is inserted into the network through an empty slot. This pattern implicity defines a variable length-frame and is issued just when an AU (access unit) loses alignment. This method allows the two end AUs on the buses to recognize the presence of misaligned stations in the networks and thus to emit the bit pattern as soon as recovery action is made necessary. This method is assessed in comparison with other synchronization mechanisms proposed in the literature in terms of realignment delay and overhead. It is shown that the proposed method is faster than other methods for networks with overall lengths up to 50 km, and, therefore, it turns out to be especially suitable for high-speed LANs and MANs