EP0022170A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of attaining communication of data packets on a local shared bus network and local shared bus network
Assignee: International Business Machines Corp
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Filing: 1980-05-29
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Granted: —
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Expires: 2000-05-29
Abstract
Abstract Asynchronous, collision-free communication of data packets is provided on a local shared bus network interconnecting a plurality of N ordered transceiving ports (1,2,3....,J,...N). The bus network includes a data bus (20) having a propagation delay time T and a control line (26) having a propagation delay from port J to port N of R(J), each port J including means (40) for ascertaining the presence of a data packet on said data bus at said port J, and being adapted to send and receive on said data bus variable length data packets. Each port J upon having a packet available for transmission executes the steps of placing a signal S(J) on said control line (26) to communicate to ports J + 1, J +2,...,N an intention to transmit a packet, delaying transmission for the time interval R(J) + T, ascertaining that no signal indicating an intention to transmit is being received at port J from any of ports 1,2,...,J- 1 , and that said data bus (20) at port J is unoccupied, transmitting the packet and terminating signal S(J). Prior to placing the signal S(J) on the control line (26), the port J ascertains that the data bus (20) is unoccupied for a time period 2T.
Inventors
- 👤 Kapali Palaniyandi Eswaran
- 👤 Vincent Carl Hamacher
- 👤 Gerald Stuart Shedler
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 03:03
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/40; H04L12/407; H04L12/413; G; G06; G06F; G06F13/00; G06F13/14; G06F13/36; G06F13/368; G06F13/376; H04L12/40006
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
178 words
A method for attaining asynchronous, collision-free communication of data packets on a local shared bus network interconnecting a plurality of N ordered transceiving ports (1,2,3,...,J,...N), the bus network including a data bus (20) having a propagation delay time T and a control line (26) having a propagation delay from port J to port N of R(J), each port J including means (40) for ascertaining the presence of a data packet on said data bus at said port J, and being adapted to send and receive on said data bus (20) variable length data packets characterised in that each port J upon having a packet available for transmission executes the steps of placing a signal S(J) on said control line (20) to communicate to ports J+l, J +2,...,N an intention to transmit a packet, delaying transmission for the time interval R(J)+T, ascertaining that no signal indicating an intention to transmit is being received at port J from any of ports 1,2,...,J-1, and that said data bus (20) at port J is unoccupied, transmitting the packet and terminating signal S(J).
Claim 2
Independent Claim
178 words
A method for attaining asynchronous, collision-free communication of data packets on a local shared bus network interconnecting a plurality of N ordered transceiving ports (1,2,3,...,J,...N), the bus network including a data bus (20) having a propagation delay time T and a control line (26) having a propagation delay from port J to port N of R(J), each port J including means (40) for ascertaining the presence of a data packet on said data bus at said port J, and being adapted to send and receive on said data bus (20) variable length data packets characterised in that each port J upon having a packet available for transmission executes the steps of placing a signal S(J) on said control line (20) to communicate to ports J+l, J +2,...,N an intention to transmit a packet, delaying transmission for the time interval R(J)+T, ascertaining that no signal indicating an intention to transmit is being received at port J from any of ports 1,2,...,J-1, and that said data bus (20) at port J is unoccupied, transmitting the packet and terminating signal S(J).
Claim 3
Dependent Claim
37 words
A method according to claim 1, further including the step of, prior to placing the signal S(J) on said control line, ascertaining that the data bus at the port J is unoccupied for a time period 2T.
Claim 4
Dependent Claim
237 words
A local shared bus network for attaining asynchronous collision-free communication of data packets, characterised in that the network includes a data bus (20) having a propagation delay time T, a plurality of N transceiving ports (1,2,3,...,J,...N), a control line (26) having a propagation delay from port J to port N of R(J), each port J comprising send means (28, S(J)) for selectively signalling to ports J+l, J+2,...,N, on said control line an intention to transmit a data packet on said data bus, receive means, B(J), for detecting the absence of a data packet on said data bus at said port J, receive means, P(J), for detecting the absence at port J of a signal on said control line from any of the ports 1,2,...,J-1, transmit control means (42) for detecting the availability of a packet for transmitting by said port J on said data bus and providing availability signal a(J), means (32) responsive to availability signal a(J) for conditioning said send means S(J), timing means for timing a period R(J)+T after the conditioning of said send means and means responsive to said timing means, said receive means, B(J) and said receive means, P(J), for transmitting said packet on said data bus and for reconditioning said send means when said bus has been observed unoccupied at B (J) and said receive means P(J) detects the absence of a signal on said control line at a time after R(J)+T.
Claim 5
Dependent Claim
237 words
A local shared bus network for attaining asynchronous collision-free communication of data packets, characterised in that the network includes a data bus (20) having a propagation delay time T, a plurality of N transceiving ports (1,2,3,...,J,...N), a control line (26) having a propagation delay from port J to port N of R(J), each port J comprising send means (28, S(J)) for selectively signalling to ports J+l, J+2,...,N, on said control line an intention to transmit a data packet on said data bus, receive means, B(J), for detecting the absence of a data packet on said data bus at said port J, receive means, P(J), for detecting the absence at port J of a signal on said control line from any of the ports 1,2,...,J-1, transmit control means (42) for detecting the availability of a packet for transmitting by said port J on said data bus and providing availability signal a(J), means (32) responsive to availability signal a(J) for conditioning said send means S(J), timing means for timing a period R(J)+T after the conditioning of said send means and means responsive to said timing means, said receive means, B(J) and said receive means, P(J), for transmitting said packet on said data bus and for reconditioning said send means when said bus has been observed unoccupied at B (J) and said receive means P(J) detects the absence of a signal on said control line at a time after R(J)+T.
Claim 6
Dependent Claim
16 words
A network according to claim 1, in which said send means includes a flip flop circuit.
Claim 7
Dependent Claim
33 words
A network according to claim 3 or 4, including another timing means responsive to availability signal a(J) for ascertaining that said data bus is unoccupied at port J for a time period 2T.
References Cited (Backward Citations)
No citation records indexed.
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