Hardware Hierarchy

Any ONI-compliant system is comprised of at least three hierarchical hardware elements:

• Controller

  • Hub

    • Device

These hardware elements are managed by a single host computer where they are governed by an Acquisition Context. The complete connectivity of the hardware hierarchy is shown below.

Host Computer [Uses API and Driver Translator to communicate with Controller]
|...||
|   || Host Interconnect 0
|   ||
|   |+-- Controller 0 [Governed by a Context & generates a Device Table]
|   |    |
|   |    | Port Interconnect 0
|   |    |
|   |    +-- Hub 0
|   |    |   |
|   |    |   +-- Device 0.0.0 (Host.Hub.Device)
|   |    |   +-- Device 0.0.1
|   |    |   +-- ..
|   |    |   +-- Device 0.0.N
|   |    |
|   |    +-- Hub 1
|   |    ·
|   |    ·
|   |    ·
|   |    +-- Hub M
|   |
|   | Host Interconnect 1
|   |
|   + Controller 1
·
·
·
|
| Host Interconnect P
|
+--- Controller P

An ONI-compliant hardware system must have at least a one controller, hub, and device. Hubs can be independent hardware elements that communicate with the controller, or can share the same hardware. For instance, an FPGA can run the controller logic, contain a hub with local devices, and connect to external hubs through a digital link. Device groups operating in different clock domains, even if they lie in the same physical hardware, must form independent hubs.