Method of and apparatus for implementing and sending an asynchronous control mechanism packet used to control bridge devices within a network of IEEE Std 1394 serial buses

摘要

An asynchronous control mechanism packet is used to send control messages and information to one or more bridge devices within a network of buses of devices. The asynchronous control mechanism packet is addressed to a device on one of the buses and is intercepted by one or more appropriate bridge devices along the path to the destination device. The asynchronous control mechanism packet is targeted at a particular bridge device or used to send control messages and information to bridge devices along a particular communications route between two devices. The asynchronous control mechanism packet includes a designation specifying that it is an asynchronous control mechanism packet and should be treated accordingly. This designation is recognized by the appropriate bridge devices. Preferably, this designation is included within the extended transaction code field of the packet. In an alternate embodiment, the designation is included within a transaction code field of the packet. In a further alternate embodiment, the designation is included within an address offset value within the packet. Instructional information within the asynchronous control mechanism packet specifies to intercepting bridge devices the type of transaction and control tasks to be performed by the bridge device when the asynchronous control mechanism packet is received.