Apparatus and method for time multiplexing a resource among a plurality of ...

[54] APPARATUS AND METHOD FOR TIME MULTIPLEXING A RESOURCE AMONG A PLURALITY OF ENTITIES

[75] Inventors: Alexander G. Fraser, Bernardsville;

Charles R. Kalmanek, Hoboken, both of N.J.; Srinivasan Keshav, Berkeley, Calif.

[73] Assignee: AT&T Bell Laboratories, Murray Hill, N.J.

[21] Appl. No.: 484,153

[22] Filed: Feb. 23,1990

[51] Int. CI.5 H04J 3/17

[52] U.S. CI 370/61; 370/80

[58] Field of Search 370/60, 94.2, 85.6,

370/79, 80, 82, 84, 61, 60.1

[56] References Cited

U.S. PATENT DOCUMENTS

4,780,870 10/1988 McHarg et al 370/60

4,797,880 1/1989 Bussey, Jr. et al 370/60

4,897,874 1/1990 Lidinsky et al 370/60

4,942,574 7/1990 Zelle 370/85.6

5,023,780 6/1991 Brearley 370/94.2

5,050,161 9/1991 Golestani 370/85.6

OTHER PUBLICATIONS

Schwartz, Mischa, Telecommunications Networks, Addison-Wesley, 1987, pp. 670-674, 686-689. Zhang, Lixia, "A New Architecture for Packet Switching Network Protocols", Doctoral Thesis, MIT Laboratory for Computer Science, 1989, pp. 49-52. Morgan, S. P., "Queuing Disciplines and Passive Congestion Control in Byte-Stream Networks", Proc. IEEE Infocom '89, Apr. 1989, pp. 712-714. Fraser, Alexander G., "Towards a Universal Data Transport System"", IEEE Journal on Selected Areas in

Apparatus and methods for time multiplexing a resource among a plurality of entities at average rates and with deterministic delays between accesses to the resource by an entity. An entity accessing the resource receives a time slot on the resource; a fixed number of time slots constitute a frame. Each entity receives a fixed allocation of time slots in the frame. When an entity has work for the resource to do, it receives access to the resource for a number of slots in each frame equal to the lesser of the number of slots required to do the work and the number of slots in the allocation. A ratecontrolled server is disclosed which defines a frame and allocations therein, as well as a hierarchy of servers which combines rate-controlled traffic with best effort traffic. In the hierarchy, a rate-controlled server activates a round-robin server when the entities served by the rate-controlled server do not require all the slots in a frame. A hierarchy of rate-controlled servers is further disclosed which permits access to the resource at widely-differing average rates. In that hierarchy, a number of slots in the frame for a given member of the hierarchy are reserved for the next member down of the hierarchy and the next member down is active only during those slots. Further disclosed are nodes of ISDN networks employing ATM which incorporate the servers and hierarchies thereof.

41 Claims, 6 Drawing Sheets