Method and apparatus for time synchronization of bus type local area

Abstract

The time of a second network is synchronized to a first network, each network having an independent timing subsystem, includes the following steps. The first network sends a first message to the second network, the first message being uniquely identified as a sync message. A first relative time is obtained within the first network of when the first message is transmitted. When the first network recognizes that the first message was sent, a second relative time is obtained to send a second message to the second network containing a real time of the first network that the first message was sent. The second network obtains a third relative time within the second network of when the first message is received. The real time of the first network contained in the second message is associated to the third relative time of the second network, thereby synchronizing the time of the second network to the time of the first network. Any skew of time associated with transmission protocols of the first and second network is thereby eliminated.