Some Preliminary Terminology

• Processor Node. See Figure 1-1 on page 11. A group of one or more processors and their associated main memory. It is interfaced to the IBA fabric via one or more HCAs (Host Channel Adapter), each of which implements one or more IBA ports.

  Figure 1-1. Host Channel Adapter

  

• Port. A bi-directional interface that connects an IBA device to an IBA link.

• Link. The bi-directional, high-speed connection between two ports on two IBA devices. At a minimum, it is implemented using one high-speed serial transmission line in each direction capable of transmitting at 2.5Gb/s, yielding 250MB/s throughput (note that each 8-bit character is converted to a 10-bit character before transmission). Optionally, a link may be implemented with four or twelve transmission lines in each direction, yielding 1GB/s or 3GB/s throughput, respectively.

• IOU and IOC. Refer to Figure 1-2 on page 11. An IO Unit (IOU) is comprised of:

  - The TCA (Target Channel Adapter) that interfaces it to the IBA fabric.

  - One or more IO Controllers (IOCs) providing the interface to various IO devices. An example of an IOC would be a mass storage array.

  Figure 1-2. Target Channel Adapter

  

• CA. The term Channel Adapter is abbreviated as CA throughout the remainder of this book.