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The computer bus path identifying the destination or location of a bus transaction. An initiator supplies an address; decoding selects the intended target. Address width describes the available address encodings, whereas data bus width describes how many bits can be carried at once.^[ref]

Selecting among initiators requesting a shared resource. An arbiter grants permission before an initiator starts its bus transaction. Fixed priority can indefinitely postpone a lower-priority requester under continuing higher-priority demand. Rotating priority can provide starvation freedom when every owner releases the resource after bounded work. Neither policy alone determines bus throughput: waiting, setup and target readiness also matter.^[ref]

One clock period in a synchronous computer bus. A bus transaction can occupy several bus cycles. An asynchronous computer bus instead coordinates progress through acknowledgments, so a clock-based count requires an additional timing model.^[ref]

The permission to use a particular computer bus resource during a specified phase. A pending grant need not authorize immediate use. Arm's AMBA Specification, revision 2.0 (section 3.11.3, figures 3-15–3-17) makes address-path handover depend on completion, and delays data bus ownership relative to address bus ownership. Consequently, a single whole-bus transaction owner is a useful simple model, but does not describe every overlapping implementation.

One requested operation and its completion, potentially including several payload transfers. A bus transaction identifies a target, specifies an operation and exchanges data or status. A CPU or DMA engine can initiate one; a target responds. The terms “master” and “slave” in older hardware documents refer to these initiator and target roles.^[ref]

An extension while a bus transaction awaits readiness. A bus wait state spends time without completing the next payload transfer. In a blocking design it also postpones another initiator's access; completion and bus ownership changes must follow the protocol.^[ref]

The computer bus paths specifying operations and coordinating progress, including requests and acknowledgments. Some control travels from initiator to target and some returns. In the diagram, bus arbitration requests and grants are shown separately from transfer control to distinguish choosing an initiator from executing its bus transaction.^[ref]

A computer bus whose communication resources serve multiple attached components. A common physical path reduces wiring, but competing bus transactions must share its capacity. Address bus, data bus and control bus name logical roles; they need not be three permanently separate bundles of wires. Some designs reuse lines for addresses and data in different phases.^[ref]