IEEE 1394: A Ubiquitous Bus

A link is an unreliable FIFO channel. As we mentioned earlier, it is an abstraction of a point-topoint wire or of a simple broadcast LAN. It is unreliable because noise or other physical problems can corrupt messages. There are many kinds of physical links, with cost and performance that vary based on length, number of drops, and bandwidth. Here are some current examples. Bandwidth is in bytes/second2, and the “+” signs mean that software latency must be added. The nature of the messages reflects the origins of the link. Computer people prefer variable-size packets, which are good for bursty traffic. Communications people prefer bits or bytes, which are good for fixedbandwidth voice traffic and minimize the latency and buffering added by collecting voice samples into a message. A physical link can be unidirectional (‘simplex’) or bidirectional (‘duplex’). A duplex link may operate in both directions at the same time (‘full-duplex’), or in one direction at a time (‘hal...

• Type: Conference
• Year: 1995
• Where: COMPCON
• Authors: Gary Hoffman, Daniel Moore
• Keywords: COMPCON 1995, Computer Networks, Full-duplex Link, Half-duplex Link, Link