EP0366866A2
Expired / Lapsed
EP
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A packet switch protocol and apparatus as for a parallel processing machine
Assignee: International Business Machines Corp
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Filing: 1989-07-08
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Granted: —
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Expires: 2009-07-08
Abstract
Abstract Packet switch protocol and circuitry for implementing it are disclosed. According to this protocol, a message transmitter of a first node in the network may send data through a data transmission link at a predetermined rate until it is signalled, via a control signal generated by a message receiver in a second node, to suspend its transmissions. The message transmitter may also be signalled to resume transmitting data. The message receiver includes a buffer memory in which messages are temporarily stored if their selected path is blocked as they pass through the network. When the amount of available space in the buffer is less than a preprogrammed threshold value, the message receiver generates the control signal to suspend message transmission. This threshold value leaves sufficient space in the buffer to store any data which may be in the pipeline between the transmitter and the receiver. When the amount of available space rises above this threshold, the message receiver indicates to the transmitter to resume transmission. A message spanning an interface during transmission may be suspended without losing spatial contiguousness. The message transmitter also transmits a signal which marks the last portion of a message. This signal is stored in the buffer with the message data and is used to delimit messages in the buffer, allowing multiple messages to be stored in one buffer without extra delimiting values.
Inventors
- 👤 William Cain Brantley, Jr.
- 👤 Wayne Stephen Groh
- 👤 Rory Dana Jackson
- 👤 Vern Alan Norton
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 05:24
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54; H04L12/56; H04L9/00; H04L9/40
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
115 words
A method of transferring data between a message transmitter in a first node of a data communications network and a message receiver in a second node of the network, comprising the steps of: A. sending message data from said message transmitter to said message receiver; B. storing said message data in a buffer of said message receiver; C. retrieving said stored message data from said buffer; and D. signalling said message transmitter to suspend the sending of message data and to resume the sending of message data when the amount of available storage locations in said buffer is respectively less than and greater than a threshold value, where said threshold value is greater than zero.
Claim 2
Independent Claim
115 words
A method of transferring data between a message transmitter in a first node of a data communications network and a message receiver in a second node of the network, comprising the steps of: A. sending message data from said message transmitter to said message receiver; B. storing said message data in a buffer of said message receiver; C. retrieving said stored message data from said buffer; and D. signalling said message transmitter to suspend the sending of message data and to resume the sending of message data when the amount of available storage locations in said buffer is respectively less than and greater than a threshold value, where said threshold value is greater than zero.
Claim 3
Dependent Claim
94 words
The method for transferring data set forth in Claim 1, wherein: the step C includes the step of applying the stored message data retrieved from said buffer to a further message transmitter contained in said second node; and the step D includes the steps of: generating a value representing the number of available storage locations in said buffer; comparing the generated value to said threshold value; emitting a control signal which is in a first state when said generated value is less than said threshold value and which is in a second state otherwise.
Claim 4
Dependent Claim
64 words
The method of transferring data set forth in Claim 2 wherein said threshold value is not less than a value representing a maximum amount of message data which may be transferred from the message transmitter to the message receiver in an amount of time substantially equal to twice the time required for a signal to be transmitted between the message transmitter and message receiver.
Claim 5
Dependent Claim
64 words
The method of transferring data set forth in Claim 3, further comprising the steps of: delaying said control signal by the amount of time substantially equal to twice the time required for a signal to be transmitted between the message transmitter and the message receiver to generate a further control signal; disabling said buffer from storing message portions responsive to said further control signal.
Claim 6
Dependent Claim
93 words
The method of transferring data set forth in claim 3 further comprising the steps of: sending, from said message transmitter to said message receiver, a message marker signal indicating when a predetermined message data portion is provided by said message transmitter; storing said message marker signal in parallel with said predetermined message data portion in said buffer; and retrieving said stored message marker signal in parallel with said predetermined message data portion from said buffer, wherein said stored message marker signal indicates when said predetermined message data portion is provided by said buffer.
Claim 7
Dependent Claim
24 words
The method of transferring data set forth in Claim 5 wherein said predetermined message data portion is the last message portion of a message.
Claim 8
Dependent Claim
154 words
A data communications network comprising: a first switch node including message transmission means for providing a sequence of message data portions and responsive to a control signal to selectively suspend and resume the providing of said sequence of message data portions; signal transmission means, coupled to said message transmission means of said first switch node, for conveying said sequence of message data portions; signal receiving means, coupled to said signal transmission means for receiving said sequence of message data portions, including: buffer means for storing said sequence of message data portions in respective data locations; control means, coupled to said buffer means for generating said control signal to condition said message transmission means to suspend and resume the providing of said sequence of message data portions when the number of available data locations in said buffer means is respectively less than and greater than a predetermined value, said predetermined value is greater than zero.
Claim 9
Dependent Claim
154 words
A data communications network comprising: a first switch node including message transmission means for providing a sequence of message data portions and responsive to a control signal to selectively suspend and resume the providing of said sequence of message data portions; signal transmission means, coupled to said message transmission means of said first switch node, for conveying said sequence of message data portions; signal receiving means, coupled to said signal transmission means for receiving said sequence of message data portions, including: buffer means for storing said sequence of message data portions in respective data locations; control means, coupled to said buffer means for generating said control signal to condition said message transmission means to suspend and resume the providing of said sequence of message data portions when the number of available data locations in said buffer means is respectively less than and greater than a predetermined value, said predetermined value is greater than zero.
Claim 10
Dependent Claim
110 words
The data communications network set forth in Claim 7, wherein: said message transmission means provides said message data portions at a predetermined rate; said control means of said message receiving means is coupled to provide said control signal to said message transmission means via said data transmission means; said data transmission means conveys said message data portions and said control signal subject to a predetermined signal propagation delay; and said predetermined value used by said control means is not less than a maximum number of message data portions which may be provided at said predetermined rate during an amount of time substantially equal to twice said predetermined signal propagation delay.
Claim 11
Dependent Claim
67 words
The data communications network set forth in Claim 8, further comprising: means, coupled to said control means for delaying said control signal by an amount of time substantially equal to twice said predetermined signal propagation delay to generate a further control signal; and means, coupled to said buffer means and responsive to said further control signal for selectively disabling said buffer means from accepting message data portions.
Claim 12
Dependent Claim
34 words
The data communications network set forth in Claim 9, wherein said predetermined value and the amount of time delay provided by said delay means are programmable to accommodate various predetermined signal propogation delay times.
Claim 13
Dependent Claim
76 words
The data communications network set forth in Claim 8, further comprising: means, coupled to said message transmission means, for providing a marker signal, via said data transmission means and in parallel with said message data portions, wherein, said marker signal indicates when a predetermined one of said message data portions is transmitted; and means, coupled to said data receiving means for storing said marker signal in said buffer means in parallel with said message data portions.
Claim 14
Dependent Claim
174 words
Circuitry for implementing a data communications protocol governing the transmission of message data portions from a message transmitter to a message receiver, through a data transmission channel having a predetermined signal propagation delay time, comprising: buffer means, coupled to said message receiver, for storing the message data portions transmitted to said message receiver; control means, coupled to said buffer means, including: means for generating a control signal which is in a first state when the amount of available storage locations in said buffer means is less than a threshold value, and in a second state otherwise; and means for transmitting said control signal to said message transmitter via said data transmission means to condition said message transmitter to suspend and resume the transmission of message data portions when said control signal is in said first and second states, respectively; wherein the threshold value is greater than a maximum number of data portions which may be transmitted to said message receiver in an amount of time substantially equal to twice said predetermined propagation delay time.
Claim 15
Dependent Claim
174 words
Circuitry for implementing a data communications protocol governing the transmission of message data portions from a message transmitter to a message receiver, through a data transmission channel having a predetermined signal propagation delay time, comprising: buffer means, coupled to said message receiver, for storing the message data portions transmitted to said message receiver; control means, coupled to said buffer means, including: means for generating a control signal which is in a first state when the amount of available storage locations in said buffer means is less than a threshold value, and in a second state otherwise; and means for transmitting said control signal to said message transmitter via said data transmission means to condition said message transmitter to suspend and resume the transmission of message data portions when said control signal is in said first and second states, respectively; wherein the threshold value is greater than a maximum number of data portions which may be transmitted to said message receiver in an amount of time substantially equal to twice said predetermined propagation delay time.
Claim 16
Dependent Claim
30 words
The circuitry set forth in claim 12 wherein said control means includes means for providing a programmable threshold value which may be changed to accommodate various predetermined propagation delay times.
References Cited (Backward Citations)
No citation records indexed.
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