Synchronizing a central timing unit to an external link via a switching network

摘要

Local timing units (in 116,136) are synchronized to a central timing unit (in 101) to determine the difference in timing between external links (e.g.103) and the local timing units so as to synchronize the centralized timing unit to the external links. This difference in timing is then transmitted to the central timing unit, which utilizes this information to adjust the timing of the central timing unit. The adjustment to the central timing unit brings it into synchronization with the selected external link. The local timing units are synchronized to the central timing unit via multiple timing paths set up through switching units (120-129) within the network. Each switching unit switches one bit of data for each group of data being received on each of the external links. In addition, information received by each of the external links designating the accuracy of the external link is transmitted to the central timing unit so that the central timing unit can select the external link having the highest accuracy. <IMAGE>