United States Patent  [ii] Patent Number: 5,319,641
Fridrich et al.  Date of Patent: Jun. 7,1994
5,029,209 7/1991 Strong, Jr. et al 380/25
5,038,346 8/1991 Courtois 370/85.6
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Chang, S. S. L. 1982, Fundamentals Handbook of Electrical and Computer Engineering vol. II Communication, Control, Devices, and Systems, John Wiley & Sons, N.Y. pp. 617-627.
Primary Examiner— Benedict V. Safourek
Assistant Examiner—Stuck Horn
Attorney, Agent, or Firm—Blakely, Sokoloff, Taylor &
An improved network for communication of message packets. The network of the present invention implements an improved collision avoidance, detection and backoff system for communication on a media between nodes. The apparatus calculates a time period P after detecting the media is idle using a formula F which is a function of a pseudo-random delay factor T. If the media remains idle during the time period P, the device may transmit a message. The apparatus further has the ability to assign messages as being either priority or non-priority messages. Priority messages may be transmitted during priority message slots preassigned to transmitting nodes. Non-priority message contend for the media during a period of time following the period set for transmission of priority messages.
48 Claims, 12 Drawing Sheets