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EP0274709A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Packet switch network protocol

Assignee: International Business Machines Corp
•
Filing: 1987-12-18
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Granted: —
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Expires: 2007-12-18
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Abstract

Abstract A first of a plurality of nodes in a multiprocessor system transmits a data packet to a second of the plurality of nodes over a data channel when the first node detects a predetermined sequence of bits on a control channel connected therebetween. The data packet is preceded on the data channel by a header which includes a plurality of fields informing the second node of the beginning of the data packet, the length of the data packet and the sequence number assigned to the packet. The data packet is followed by a field which enables the second node to determine whether the data packet was received correctly. If the second node determines that the data packet was received correctly, the data packet is stored in the node and an acknowledgement sequence is transmitted to the first node over the control channel. However, if an error occurs during the transmission of the data packet, the protocol enters an error state by removing all signal information from the data and control channels. Thereafter, a recovery processor, which is associated with each of the plurality of nodes, analyzes the state of the nodes at the time of the error in order to determine which corrective action needed to recover the respective node. The data link protocol also facilitates the transmission of a data packet from a first node through an intermediate node to a final node without storing the data packet in the intermediate node.

Inventors

  • 👤 Bartholomew Blaner

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-05 20:21
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54; H04L12/56; H04L9/00; H04L9/40; H04L69/00; H04L69/30; H04L69/32; H04L69/322; H04L69/324

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 118 words
A method of communicating serially and for recovering data in an asynchronous digital network system, the steps comprising: (a) transmitting a packet of data from a transmitter to a receiver operatively connected thereto over a data channel; (b) analyzing said data packet for errors therein, said analysis being performed by said receiver; (c) transmitting a negative control packet from said receiver to said transmitter over a control channel when an error in said data packet has been detected, disabling said control channel and disabling said receiver to prevent subsequent data from being received thereby; (d) analyzing said control packet for errors therein; and (e) disabling said data channel upon receiving said negative control packet over said control channel.
Claim 2
Independent Claim 118 words
A method of communicating serially and for recovering data in an asynchronous digital network system, the steps comprising: (a) transmitting a packet of data from a transmitter to a receiver operatively connected thereto over a data channel; (b) analyzing said data packet for errors therein, said analysis being performed by said receiver; (c) transmitting a negative control packet from said receiver to said transmitter over a control channel when an error in said data packet has been detected, disabling said control channel and disabling said receiver to prevent subsequent data from being received thereby; (d) analyzing said control packet for errors therein; and (e) disabling said data channel upon receiving said negative control packet over said control channel.
Claim 3
Dependent Claim 54 words
The method as recited in claim 1 further comprising the steps of: (f) after step (a), transmitting said data packet to a storage means operatively connected to said receiver; and (g) transmitting said data packet over said data channel from said storage means to a subsequent receiver when the transmission path thereto is available.
Claim 4
Dependent Claim 31 words
The method as recited in claim 2 further comprising the step of cutting through said storage means by said data packet when said storage means contains no previously stored data packet.
Claim 5
Dependent Claim 215 words
In a network having a plurality of digital devices, a method of ensuring integrity of data communication among said digital devices while data is being transmitted from a transmitter device to a destination receiver device, the steps comprising: (a) transmitting a packet of data from a first transmitter to a first receiver having forwarding capability, said transmission occurring over a data channel; (b) analyzing said data packet for errors therein, said analysis being performed by said first receiver; (c) forwarding said data packet from said first receiver to a second receiver having forwarding capability over said data channel if no error in said data packet is detected; (d) transmitting a negative control packet from said first receiver to said -transmitter over a control channel connected therebetween when an error in said data packet is detected by said first receiver; (e) retransmitting said data packet over said data channel to said first receiver from said transmitter when said negative control packet is received thereby; and (f) repeating steps (a) through (e) until a predetermined destination receiver receives said data packet without error, whereby an error in said data packet detected by any of said receivers in the transmission path results in retransmission of said data packet thereto over said data channel by its immediate predecessor device.
Claim 6
Dependent Claim 215 words
In a network having a plurality of digital devices, a method of ensuring integrity of data communication among said digital devices while data is being transmitted from a transmitter device to a destination receiver device, the steps comprising: (a) transmitting a packet of data from a first transmitter to a first receiver having forwarding capability, said transmission occurring over a data channel; (b) analyzing said data packet for errors therein, said analysis being performed by said first receiver; (c) forwarding said data packet from said first receiver to a second receiver having forwarding capability over said data channel if no error in said data packet is detected; (d) transmitting a negative control packet from said first receiver to said -transmitter over a control channel connected therebetween when an error in said data packet is detected by said first receiver; (e) retransmitting said data packet over said data channel to said first receiver from said transmitter when said negative control packet is received thereby; and (f) repeating steps (a) through (e) until a predetermined destination receiver receives said data packet without error, whereby an error in said data packet detected by any of said receivers in the transmission path results in retransmission of said data packet thereto over said data channel by its immediate predecessor device.

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