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US4347498A
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Method and means for demand accessing and broadcast transmission among ports in a distributed star network
Assignee: International Business Machines Corp
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Filing: 1979-11-21
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Granted: 1982-08-31
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Expires: 1999-11-21
Abstract
Abstract A demand access broadcast transmission method and means is capable of supporting random port access and any-to-any transmission at very high data rates. A communication medium (FIG. 2) formed from an inverted tree network of nodes (1, 18, 22) and full duplex connecting links (13, 17, 19) permits the establishment of a path lock up-link through the network from a demanding port to a root node on a first-come first-serve demand access basis with arbitration at each distinct tree node level (FIG. 3). Broadcast transmission is perfected down-link over all fan-out paths from the root node. Collision is avoided by locking a path to a port and by limiting race conditions among active ports to only the leading edges of messages. Thus, relinquishment of a broadcast channel overlapped with transmission of a message does not result in path seizure since the occurrence of message leading edges is the singular path connection invoking event.
Inventors
- 👤 Robert P. Lee
- 👤 Felix H. Closs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:15
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54; H04L12/56; H04L12/28; H04L12/44
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
154 words
A data communications system comprising: a transmission medium formed from an inverted three network of nodes and full duplex connecting links, the tree network having a network root node, said root node of a tree or subtree thereof having an in-degree of zero, each duplex link including an up-link and a down-link respectively defining a signal path direction toward or away from the network root node, each up and down-link being in either an idle or occupied state; a plurality of transceiving ports attaching the network at selected nodes, ready ones of the ports transmitting messages at will; each nodes includes: means for ascertaining whether the state of each terminating up-link and down-link is idle or occupied; and means responsive to the first occurring ascertained state transition from idle to occupied among the terminating up-links for completing an exclusive signal path connection to an outbound up-link only if the outbound up-link is concurrently idle.
Claim 2
Dependent Claim
154 words
A data communications system comprising: a transmission medium formed from an inverted three network of nodes and full duplex connecting links, the tree network having a network root node, said root node of a tree or subtree thereof having an in-degree of zero, each duplex link including an up-link and a down-link respectively defining a signal path direction toward or away from the network root node, each up and down-link being in either an idle or occupied state; a plurality of transceiving ports attaching the network at selected nodes, ready ones of the ports transmitting messages at will; each nodes includes: means for ascertaining whether the state of each terminating up-link and down-link is idle or occupied; and means responsive to the first occurring ascertained state transition from idle to occupied among the terminating up-links for completing an exclusive signal path connection to an outbound up-link only if the outbound up-link is concurrently idle.
Claim 3
Dependent Claim
37 words
A data communication system according to claim 1 wherein each node further includes: a pulse source; and means responsive to an ascertained idle state on all terminating up-links for coupling said pulse source to an outbound up-link.
Claim 4
Dependent Claim
71 words
A data communication system according to claim 1, wherein the state ascertaining means includes: means for terminating an up-link; a first register; means responsive to a transition from a time varying waveform to a waveform of constant slope on said up-link for setting the first register to a first value and responsive to a transition from a constant to a time varying waveform for setting the register to a second value.
Claim 5
Dependent Claim
78 words
A data communications system according to claim 1, wherein the signal path connection means includes: means responsive to the initiation of a signal path connection to an outbound up-link for sensing the duration of the round trip propagation delay between a selected tree node and the network root node and for invoking a wrap-around loop connection between the terminating up-links and outbound down-links at the network root node upon the second round trip propagation's exceeding a predetermined amount.
Claim 6
Dependent Claim
37 words
A data communication system according to claim 1, wherein the signal path connection means includes: means responsive to a state transition from occupied to idle upon an up-link within an established connection for relinquishment of said connection.
Claim 7
Independent Claim
168 words
A method for any-to-any port transmission of messages through an inverted tree network of nodes and full duplex connecting links, the tree network having a network root node, said root node of the tree or sub-tree thereof having an in-degree of zero, each duplex link including an up-link and a down-link respectively defining a signal path direction toward or away from the network root node, the method being executable by ready-to-transmit ones of a plurality of transceiving ports individually coupling the network at selected nodes, comprising the steps of: establishing a message initiated path lock up-link through the network from a ready-to-transmit one of the ports to the network root node only by way of a first come, first serve demand access discipline among the up-links terminating at each distinct tree node level to a concurrently idle out-bound up-link; and broadcast transmitting any message over all down-links fanning out from the network root node, which message was received over an up-link path connection to said network root node.
Claim 8
Independent Claim
168 words
A method for any-to-any port transmission of messages through an inverted tree network of nodes and full duplex connecting links, the tree network having a network root node, said root node of the tree or sub-tree thereof having an in-degree of zero, each duplex link including an up-link and a down-link respectively defining a signal path direction toward or away from the network root node, the method being executable by ready-to-transmit ones of a plurality of transceiving ports individually coupling the network at selected nodes, comprising the steps of: establishing a message initiated path lock up-link through the network from a ready-to-transmit one of the ports to the network root node only by way of a first come, first serve demand access discipline among the up-links terminating at each distinct tree node level to a concurrently idle out-bound up-link; and broadcast transmitting any message over all down-links fanning out from the network root node, which message was received over an up-link path connection to said network root node.
Claim 9
Dependent Claim
12 words
A method according to claim 6, wherein the messages consist of packets.
Claim 10
Dependent Claim
46 words
A method according to claim 6, wherein each message includes an addressee port, the method steps further comprising: confirming to the originating port that its message was delivered to the addressee port by receipt of the down-link echo of the transmitted message by said originating port.
Claim 11
Dependent Claim
76 words
A method according to claim 6, wherein the network is operable in a data and idle mode, the method steps further comprising: impressing signals indicative of the idle mode upon up-links not transmitting messages; sensing at the up-links terminating in each node any signal change from idle-to-data-modes; and causing the fist come, first served demand access discipline to be executed at any given node upon sensing idle-to-data-mode transition upon any up-links terminating in the given node.
Claim 12
Dependent Claim
41 words
A method according to claim 9, wherein the idle mode signals impressed upon up-links are formed from a predetermined pattern, mode transition being sensed as the change in the up-link from any other pattern to the predetermined pattern (FIGS. 7, 11).
Claim 13
Dependent Claim
17 words
A method according to claim 10, wherein the predetermined pattern consists of a series of consecutive pulses.
Claim 14
Dependent Claim
23 words
A method according to claim 10, wherein the predetermined pattern consists of a constant level, while the nonpredetermined pattern consists of ternary levels.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-08-30 | 1986-03-01 | 1986-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-08-30 | 1990-03-01 | 1990-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-08-30 | 1994-03-01 | 1994-08-31 | $7700.00 | Window Closed / Lapsed |