| 摘要 |
An asynchronous, fiber optic, ring network (10) includes a number of nodes where data enters and exits the network. Each of these nodes has its own clock (640) to provide timing needed by equipment at that node. So that synchronous data can be transmitted between predetermined nodes, a master node (100, 200) provides timing information which may be used at any node to synchronize its clock. Timing information comprises the propagation delay around the ring (ring latency) as measured by the master node. This measure of propagation delay is transmitted by the master node as an information packet (310) available at all nodes. Synchronization of any other node (110,300) with the master requires that the other node perform its own measurement of propagation delay, compare its measurement with that of the master node, and make adjustments to its own clock that tend to decrease the difference between these measurements. <IMAGE> |
