Patent EP0225024A2 successfully refreshed from Google Patents.
EP0225024A2
Expired / Lapsed
EP
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Data transmission system
Assignee: Fujitsu Services Ltd
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Filing: 1986-10-16
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Granted: —
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Expires: 2006-10-16
Abstract
Abstract A data transmission system is described, comprising a plurality of processing nodes (10-13). At any given time, one of the nodes acts as a star coupler, for broadcasting messages to all the other nodes. This node uses a plurality of counters (361-363) to keep track of the amount of available space in the receive buffers (351) of the other nodes. Whenever a message is broadcast, all the counters are decremented. Conversely, whenever an acknowledgement signal is received, indicating that one of the other nodes has removed a message from its buffer, the corresponding counter is incremented. If any of the counters indicates that a buffer is full or nearly full, broadcasting is suspended. If any of the nodes develops a fault, preventing it from removing messages from its buffer, it transmits a constant stream of acknowledgement signals, thereby preventing the corresponding counter from indicating "full" and hence allowing the system to continue running.
Inventors
- 👤 Colin Martin Duxbury
- 👤 Raymond Yates
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 22:19
CPC Classifications
H; H04; H04L; H04L47/00; H04L47/10; H04L47/30; H04L12/00; H04L12/54; H04L12/56; H04L47/15
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
240 words
A data transmission system comprising a first node and a plurality of further nodes connected to the first node by respective data transmission links for transmitting messages from the first node to the further nodes, wherein each of the further nodes has a buffer (351) for receiving messages and each of the further nodes, when it removes a message from its buffer, returns an acknowledgement signal to the first node, and wherein the first node includes a plurality of indication means (361-363), one for each of the further nodes, for producing an indication of the amount of available space in the buffers of each of the further nodes, each indication means being updated whenever a message is sent to the corresponding node or an acknowledgement signal is received from the corresponding node, characterised in that (a) the first node is arranged to broadcast each message over all the links (XCH1-XCH3) to all the further nodes and thereupon to update all the indication means (361-363), and is operable to suspend broadcasting if any one of the indication means indicates that the corresponding buffer (351) is full or is becoming full, and (b) each of said further nodes includes means (143-146) operative in the event of a fault preventing that node from removing messages from its buffer, for sending a constant stream of acknowledgement signals to the first node, thereby preventing the corresponding indication means from indicating that the buffer is full.
Claim 2
Dependent Claim
240 words
A data transmission system comprising a first node and a plurality of further nodes connected to the first node by respective data transmission links for transmitting messages from the first node to the further nodes, wherein each of the further nodes has a buffer (351) for receiving messages and each of the further nodes, when it removes a message from its buffer, returns an acknowledgement signal to the first node, and wherein the first node includes a plurality of indication means (361-363), one for each of the further nodes, for producing an indication of the amount of available space in the buffers of each of the further nodes, each indication means being updated whenever a message is sent to the corresponding node or an acknowledgement signal is received from the corresponding node, characterised in that (a) the first node is arranged to broadcast each message over all the links (XCH1-XCH3) to all the further nodes and thereupon to update all the indication means (361-363), and is operable to suspend broadcasting if any one of the indication means indicates that the corresponding buffer (351) is full or is becoming full, and (b) each of said further nodes includes means (143-146) operative in the event of a fault preventing that node from removing messages from its buffer, for sending a constant stream of acknowledgement signals to the first node, thereby preventing the corresponding indication means from indicating that the buffer is full.
Claim 3
Dependent Claim
16 words
A system according to Claim 1 wherein each of said indication means (361-363) comprises a counter.
Claim 4
Dependent Claim
42 words
A system according to Claim 1 or 2 wherein the first node includes "single message" mode control means (1315,1316) which, when activated, allows a message to be broadcast only if all the indication means (361-363) indicate that the corresponding buffers are empty.
Claim 5
Independent Claim
38 words
A system according to any preceding claim wherein the first node includes a plurality of further buffers (321-323) for receiving messages from said further nodes, and is arranged to broadcast each such message to all said further nodes.
Claim 6
Dependent Claim
79 words
A system according to Claim 4 wherein the first node includes "slow message" mode control means (88,89,810,811) which, when unactivated, allows the first node to start broadcasting a message before it has been completely received into one of said further buffers (321-323), and which, when activated, allows the first node to start broadcasting a message only when it has been completely received into one of said further buffers, allowing each message to be fully checked before it is broadcast.
Claim 7
Independent Claim
22 words
A system according to any preceding claim wherein each of said nodes is a processing node, including a data processing unit (PROC).
References Cited (Backward Citations)
EP0042447A1
Cited
US4380063A
Cited
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