Medium access control (MAC) protocol for single bus multimedia fair access local area network
First Claim
1. A method of providing data transmission utilizing a medium access control protocol with a fair cell-access scheme in a local area network having a unidirectional looped bus and a plurality of network stations coupled to the bus for asynchronous cell transmissions from one network station to other network stations, said method comprising the steps of:
- generating continuously time slots from a head-of-bus to the bus, each of the time slots including a busy bit, a reserved bit, and a slot reservation bit;
providing each of said plurality of network stations with cells to be transported in said time slots;
setting the busy bit and delivering a cell through a current time slot by one of said plurality of network stations if neither the busy bit nor the reserved bit is set;
setting the slot reservation bit to reserve a future time slot by said one of said plurality of network stations from the head-of-bus when the busy bit is set and the slot reservation bit is not set;
setting the reserved bit in the next slot generated by the head-of-bus to indicate a reserved time slot by the head-of-bus when a slot with its slot reservation bit set is received; and
delivering a cell through said reserved time slot by said one of said plurality of network stations that had recently set the slot reservation bit when the busy bit is not set and the reserved bit is set.
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Abstract
A method provides for data transmission utilizing medium access control protocol with a fair cell-access scheme in a local area network having a unidirectional looped bus and a plurality of network stations coupled to the bus for asynchronous cell transmissions from one network station to other network stations. A head-of-bus is used to generate continuously time slots to the bus. Each of the time slots includes a busy bit, a reserved bit, and a slot reservation bit. The medium access control protocol makes use of the busy bit, the reserved bit, and the slot reservation bit so as to provide fair bandwidth sharing by all of the network stations connected to the bus.
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Citations
14 Claims
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1. A method of providing data transmission utilizing a medium access control protocol with a fair cell-access scheme in a local area network having a unidirectional looped bus and a plurality of network stations coupled to the bus for asynchronous cell transmissions from one network station to other network stations, said method comprising the steps of:
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generating continuously time slots from a head-of-bus to the bus, each of the time slots including a busy bit, a reserved bit, and a slot reservation bit; providing each of said plurality of network stations with cells to be transported in said time slots; setting the busy bit and delivering a cell through a current time slot by one of said plurality of network stations if neither the busy bit nor the reserved bit is set; setting the slot reservation bit to reserve a future time slot by said one of said plurality of network stations from the head-of-bus when the busy bit is set and the slot reservation bit is not set; setting the reserved bit in the next slot generated by the head-of-bus to indicate a reserved time slot by the head-of-bus when a slot with its slot reservation bit set is received; and delivering a cell through said reserved time slot by said one of said plurality of network stations that had recently set the slot reservation bit when the busy bit is not set and the reserved bit is set. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for data transmission utilizing a medium access control protocol with a fair cell-access scheme in a local area network having a unidirectional looped bus and a plurality of network stations coupled to the bus for asynchronous cell transmissions from one network station to other network stations, said apparatus comprising:
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a head-of-bus for generating continuously time slots to the bus, each of the time slots including a busy bit, a reserved bit, and a slot reservation bit; each of said plurality of network stations being supplied with cells to be transported in said time slots; said one of said plurality of network stations setting the busy bit and delivering a cell through a current time slot if neither the busy bit nor the reserved bit is set; said one of said plurality of network stations setting the slot reservation bit in the current time slot to reserve a future time slot from the head-of-bus when the busy bit is set and the slot reservation bit is not set in the current time slot; said head-of-bus setting the reserved bit in the next slot generated by the head-of-bus when a slot with its slot reservation bit set is received; and said one of said plurality of network stations that had recently set the slot reservation bit delivering a cell through a current time slot when the busy bit is not set and the reserve bit is set in the current time slot. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification