ABSTRACT
In IEEE 1394, two levels of service are available: “asynchronous” packets are sent on a best effort basis while “isochronous” packets are guaranteed to be delivered with bounded latency. The isochronous packets are labeled with 6-bit “channel” numbers. First, the node must acquire the necessary bandwidth and a channel from the Bandwidth Available and Channels Available registers at the IRM by means of asynchronous traffic. Asynchronous transfers use 64-bit fixed addressing, where the upper 16 bits of each address represent the node ID. The higher orders 10 bits specify a bus ID and lower order 6 bits specify a physical ID. The node ID is subject to reassignment each time bus reset (Chandramohan et al. 2002). During bus configuration, a treelike topology is built; each node is assigned a physical node number and also sends self-ID packet(s) that is used by the management layer. A bus manager shall have the capability to monitor self-ID packets. It may set its own force root variable to TRUE and initiate a bus reset in order to become the IRM at the same time, which benefits information sharing.
