Frame synchronized ring system and method

[54] FRAME SYNCHRONIZED RING SYSTEM AND METHOD

[75] Inventors: K. Pertti T. Raatikainen, Vantaa; Juha E. Zidbeck, Espoo; Olli Martikainen,

Helsinki, all of Finland

[73] Assignee: Valtion Teknillinen Tutkimuskeskus,

Helsinki, Finland

[21] Appl. No.: 839,610

[22] Filed: Apr. 15, 1997

Related U.S. Application Data

[63] Continuation of Ser. No. 422,233, Apr. 14,1995, abandoned.

[51] Int. C I. H04L 12/43

[52] U.S. CI 370/410; 370/439; 370/460;

370/462

[58] Field of Search 370/400, 410-412,

370/438, 439-440, 443, 445, 447, 458, 459, 460^161, 462-522

[56] References Cited

U.S. PATENT DOCUMENTS

M. Zafirovic-Vukotic, I. G. Niemegeers, Performance Modeling of the Orwell Basic Access Mechanism, Computer Communications Rev. 17, Special Issue, pp. 35-48, 1987.

J. Harju, P. Raatikainen, T. Reinikka, J. Zidbeck, Analysis of a Link Layer Protocol for a High Speed Data Bus, Proceedings of the 18th Conference on Local Computer Networks, IEEE Computer Society Press, pp. 432-439, 1993.

Motorola University Prss, The Basics Book of OSI and Network Management, Sep., 1992.

VTT Technical Research Centre of Finland, Frame Synchronized Ring. 12.

Primary Examiner—Min Jung

Attorney, Agent, or Firm—Merchant, Gould, Smith, Edell, Welter & Schmidt, PA.

A device-implemented method of data communications in a communications network is provided. A particular node which has data information to send is granted a turn when an incoming request signal is in an "off" state. An empty frame is captured and a frame of data information is sent in a downstream direction on the communication network when the particular node is granted a turn. An outgoing request signal is set in an "off' state when the empty frame is captured. The outgoing request signal is set in an "on" state when the empty frame is not captured and a turn has been granted. The outgoing request signal is set in an "on" state when the incoming request signal is in an "on" state and an incoming frame is not empty. The outgoing request signal preferably is sent in an upstream direction on the communication network where the upstream direction is different from the downstream direction on the communication network. A data communication network node and a communication network, which operate in accordance with the above-described method, also are provided.

29 Claims, 11 Drawing Sheets