Patent US4444200A successfully refreshed from Google Patents.
Patent US2158267A successfully refreshed from Google Patents.
Patent US5319641A successfully refreshed from Google Patents.
US5319641A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiaccess carrier sensing network communication protocol with priority messages
Assignee: Echelon Systems Corp
•
Filing: 1990-12-03
•
Granted: 1994-06-07
•
Expires: 2010-12-03
Abstract
Abstract An improved network for communication of message packets. The network of the present invention implements an improved collision avoidance, detection and backoff system for communication on a media between nodes. The apparatus calculates a time period P after detecting the media is idle using a formula F which is a function of a pseudo-random delay factor T. If the media remains idle during the time period P, the device may transmit a message. The apparatus further has the ability to assign messages as being either priority or non-priority messages. Priority messages may be transmitted during priority message slots preassigned to transmitting nodes. Non-priority message contend for the media during a period of time following the period set for transmission of priority messages.
Inventors
- 👤 Marek J. Fridrich
- 👤 Glen M. Riley
- 👤 Robert A. Dolin, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:25
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/40; H04L12/40143; H04L12/40156; G; G05; G05D; G05D23/00; G05D23/19; G05D23/1902; G05D23/1905; H04L12/407; H04L12/413; H04L12/40163
Claims Analysis
Total Claims: 62
Claim 1
Independent Claim
150 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F including as a factor a pseudo-random delay factor T, said pseudo-random delay factor T representing an integer number of time slots S, said integer number of time slots S varying dependent on backlog of the network; e) said first device monitoring said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 2
Independent Claim
150 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F including as a factor a pseudo-random delay factor T, said pseudo-random delay factor T representing an integer number of time slots S, said integer number of time slots S varying dependent on backlog of the network; e) said first device monitoring said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 3
Dependent Claim
19 words
The method as recited by claim 1 wherein said pseudo-random delay factor T is specified as an integer number.
Claim 4
Dependent Claim
16 words
The method as recited by claim 2 wherein said backlog is estimated by said first device.
Claim 5
Dependent Claim
41 words
The method as recited by claim 1 wherein said medium is considered idle when: a) said medium is in a first binary state; and b) said first device has not detected a transition on said medium for a time period Beta1.
Claim 6
Dependent Claim
12 words
The method of claim 4 wherein said medium comprises twisted pair wiring.
Claim 7
Dependent Claim
67 words
The method as recited by claim 5 wherein said pseudo-random delay factor T is representative of an integer number of time slots S, each of said time slots S of duration Beta2, where Beta2 meets the constraint: Beta2>(2*Tau.sub.p)+Tau.sub.m and where Tau p is representative of a physical propagation of said medium and Tau m is representative of a detection and turnaround delay characteristic of said first device.
Claim 8
Dependent Claim
47 words
The method as recited by claim 6 wherein said time period Beta1 is limited by the constraint: Beta1>(2*Tau.sub.p)+Tau.sub.m and, where Tau p is representative of a physical propagation of said medium and Tau m is representative of a detection and turnaround delay characteristic of said first device.
Claim 9
Dependent Claim
13 words
The method as recited by claim 1 wherein said medium comprises power lines.
Claim 10
Dependent Claim
13 words
The method as recited by claim 1 wherein said medium comprises radio waves.
Claim 11
Dependent Claim
12 words
The method as recited by claim 1 wherein said medium comprises microwaves.
Claim 12
Dependent Claim
44 words
The method as recited by claim 1 wherein said messages transmitted on said medium are encoded utilizing differential Manchester coding and the medium is considered idle during periods when the voltage remains level during both a first and second interval of a clock cycle.
Claim 13
Dependent Claim
35 words
The method as recited by claim 1 wherein said pseudo-random delay factor T is calculated including a backlog factor BL, said backlog factor BL based on the backlog of messages for transmission on said medium.
Claim 14
Dependent Claim
22 words
The method as recited by claim 12 wherein message packets are classified as either priority message packets or a non-priority message packets.
Claim 15
Dependent Claim
44 words
The method as recited by claim 13 wherein said plurality of devices in a network further comprises a second device, a priority slot is preassigned to said first device, and message packets classified as priority are communicated onto the medium during said priority slot.
Claim 16
Dependent Claim
62 words
The method as recited by claim 14 wherein, for non-priority messages, said backlog factor BL is in the range of (N+1) . . . (N+1+(w base *BL))where: N is the number of priority slots; w base is a predetermined number of time slots S; and BL is a backlog factor based on an estimated backlog of messages for transmission on said medium.
Claim 17
Dependent Claim
14 words
The method as recited by claim 15 wherein w base is equal to 16.
Claim 18
Dependent Claim
57 words
The method as recited by claim 12 wherein said backlog factor BL calculated by said first device, said backlog factor BL being incremented each time a message packet is received or transmitted by said first device and said backlog factor BL being decremented each time a busy cycle is detected on said medium by said first device.
Claim 19
Dependent Claim
31 words
The method as recited by claim 17 wherein said backlog factor BL is incremented by an estimate of the number of messages to be generated responsive to the received message packet.
Claim 20
Dependent Claim
29 words
The method as recited by claim 18 wherein said received message packet includes an estimate of the number of messages to be generated responsive to the received message packet.
Claim 21
Dependent Claim
41 words
The method as recited by claim 1 wherein said plurality of devices in a network further comprises a second device, a priority slot is preassigned to said first device, and said first device transmits priority message packets during said priority slot.
Claim 22
Dependent Claim
142 words
In a network of devices, said network for facilitating sending and receiving of messages between said devices, said network comprising a medium for transmitting said messages, an improved method for managing message traffic on said medium comprising the steps of: a) a first of said devices monitoring said medium; b) said first device preparing a message for transmission on said medium, said first device continuing to monitor said medium during said step (b); c) said first device sensing said medium is idle; d) said first device waiting a time period P after completing said step (c), said time period P calculated utilizing a backlog counter BL as a factor, said first device continuing to monitor said channel during said time period P; e) said first device transmitting said message on said medium if said medium remains idle during said time period P.
Claim 23
Dependent Claim
142 words
In a network of devices, said network for facilitating sending and receiving of messages between said devices, said network comprising a medium for transmitting said messages, an improved method for managing message traffic on said medium comprising the steps of: a) a first of said devices monitoring said medium; b) said first device preparing a message for transmission on said medium, said first device continuing to monitor said medium during said step (b); c) said first device sensing said medium is idle; d) said first device waiting a time period P after completing said step (c), said time period P calculated utilizing a backlog counter BL as a factor, said first device continuing to monitor said channel during said time period P; e) said first device transmitting said message on said medium if said medium remains idle during said time period P.
Claim 24
Dependent Claim
26 words
The improvement as recited by claim 21 further comprising the step of initiating said backlog counter BL to a first value at initialization of said network.
Claim 25
Dependent Claim
32 words
The improvement as recited by claim 21 further comprising the step of incrementing said backlog counter BL based on information received by said first device detailing expected message transmissions on said medium.
Claim 26
Dependent Claim
47 words
The improvement as recited by claim 23 wherein said information detailing expected message transmissions a field N contained in the header of a transmitted message M, said field N designating a number of expected packets to be generated as a result of transmission of said message M.
Claim 27
Dependent Claim
28 words
The improvement as recited by claim 24 wherein said step of incrementing said backlog counter BL is not carried out where said backlog counter BL exceeds a threshold.
Claim 28
Dependent Claim
23 words
The improvement as recited by claim 25 wherein said threshold is less than or equal to the number of nodes on said network.
Claim 29
Dependent Claim
21 words
The improvement as recited by claim 21 wherein said backlog counter BL is adjusted periodically based on feedback from said network.
Claim 30
Independent Claim
171 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, said network comprising a plurality of devices including a first device and a second device; independent of said second device said first device being preassigned a priority slot n for communication of priority messages, and independent of said first device said second device being preassigned a priority slot m for communication of priority messages, where m is not equal to n, said method of avoiding collisions comprising the steps of: a) said first device preparing a first message packet for transmission on said medium, said first message being a priority message; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device continuing to monitor said medium for n-1 priority slots; e) said first device communicating said message packet onto the medium during said priority slot n if said medium remains idle during priority slots 1 through n-1.
Claim 31
Independent Claim
171 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, said network comprising a plurality of devices including a first device and a second device; independent of said second device said first device being preassigned a priority slot n for communication of priority messages, and independent of said first device said second device being preassigned a priority slot m for communication of priority messages, where m is not equal to n, said method of avoiding collisions comprising the steps of: a) said first device preparing a first message packet for transmission on said medium, said first message being a priority message; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device continuing to monitor said medium for n-1 priority slots; e) said first device communicating said message packet onto the medium during said priority slot n if said medium remains idle during priority slots 1 through n-1.
Claim 32
Dependent Claim
24 words
The method as recited by claim 28 an indicator is set in said first message packet to indicate the message is a priority message.
Claim 33
Dependent Claim
142 words
A networked communication system having at least a first device and a second device, said first device coupled with said second device over a medium, said first device comprising: (a) means for preparing a first message packet for transmission on said medium; (b) means for sensing said medium to determine if said medium is idle; (c) means for computing a time period P after detecting said medium is idle, said means for computing said time period P using a formula F, said formula F including as a factor a pseudo-random delay factor T; said pseudo-random delay factor T representing and integer number of time slots S, said integer number of time slots S varying dependent on backlog of the network; and (d) means for transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 34
Dependent Claim
142 words
A networked communication system having at least a first device and a second device, said first device coupled with said second device over a medium, said first device comprising: (a) means for preparing a first message packet for transmission on said medium; (b) means for sensing said medium to determine if said medium is idle; (c) means for computing a time period P after detecting said medium is idle, said means for computing said time period P using a formula F, said formula F including as a factor a pseudo-random delay factor T; said pseudo-random delay factor T representing and integer number of time slots S, said integer number of time slots S varying dependent on backlog of the network; and (d) means for transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 35
Dependent Claim
117 words
In a network of devices, said network for facilitating sending and receiving of messages between said device, said network including a medium for transmitting said messages, an improved means for managing message traffic on said medium wherein a first of said devices comprises: (a) means for monitoring said medium to determine if said medium is idle; (b) means for preparing a first message packet for transmission on said medium; (c) means for calculating a time period P after determining said medium is idle, said time period P utilizing a backlog counter BL as a factor; and (d) means for transmitting said first message packet on said medium if said medium remains idle during said time period P.
Claim 36
Dependent Claim
117 words
In a network of devices, said network for facilitating sending and receiving of messages between said device, said network including a medium for transmitting said messages, an improved means for managing message traffic on said medium wherein a first of said devices comprises: (a) means for monitoring said medium to determine if said medium is idle; (b) means for preparing a first message packet for transmission on said medium; (c) means for calculating a time period P after determining said medium is idle, said time period P utilizing a backlog counter BL as a factor; and (d) means for transmitting said first message packet on said medium if said medium remains idle during said time period P.
Claim 37
Dependent Claim
159 words
A networked communication system including a medium for coupling in communication at least a first device and a second device; said first device comprising: (a) means for storing a preassigned priority slot number N, said preassigned priority slot number N being preassigned to said first device; (b) means for preparing a first message packet for transmission on said medium, said first message packet being a priority message; (c) means for sensing said medium to determine if said medium is idle; (d) means for monitoring said medium during a plurality of priority slots 1 through N-1; and (e) means for communicating said first message packet onto said medium during priority slot N if said medium remains idle during said plurality of priority slots 1 through N-1; and said second device comprising: (f) means for storing a preassigned priority slot number M, where M is not equal to N, said preassigned priority slot number M being preassigned to said second device.
Claim 38
Dependent Claim
159 words
A networked communication system including a medium for coupling in communication at least a first device and a second device; said first device comprising: (a) means for storing a preassigned priority slot number N, said preassigned priority slot number N being preassigned to said first device; (b) means for preparing a first message packet for transmission on said medium, said first message packet being a priority message; (c) means for sensing said medium to determine if said medium is idle; (d) means for monitoring said medium during a plurality of priority slots 1 through N-1; and (e) means for communicating said first message packet onto said medium during priority slot N if said medium remains idle during said plurality of priority slots 1 through N-1; and said second device comprising: (f) means for storing a preassigned priority slot number M, where M is not equal to N, said preassigned priority slot number M being preassigned to said second device.
Claim 39
Independent Claim
121 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determined if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F varies dependent on the backlog; e) said first device continuing to monitor said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 40
Independent Claim
121 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determined if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F varies dependent on the backlog; e) said first device continuing to monitor said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 41
Dependent Claim
16 words
The method as recited by claim 33 wherein said backlog is estimated by said first device.
Claim 42
Independent Claim
210 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determine if said medium is idle, as determined when said medium is in a first binary state and said first device has not detected a transition on said medium for a time period Betal; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F including as a factor a pseudo-random delay factor T, said pseudo-random delay factor T representing an integer number of time slots S, each of said time slots S of duration Beta2, where Beta2 meets the constraint: Beta2>(2*Tau.sub.p)+Tau.sub.m and where Tau p is representative of a physical propagation of said medium and Tau m is representative of a detection and turnaround delay characteristic of said first device; e) said first device continuing to monitor said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 43
Independent Claim
210 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determine if said medium is idle, as determined when said medium is in a first binary state and said first device has not detected a transition on said medium for a time period Betal; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F including as a factor a pseudo-random delay factor T, said pseudo-random delay factor T representing an integer number of time slots S, each of said time slots S of duration Beta2, where Beta2 meets the constraint: Beta2>(2*Tau.sub.p)+Tau.sub.m and where Tau p is representative of a physical propagation of said medium and Tau m is representative of a detection and turnaround delay characteristic of said first device; e) said first device continuing to monitor said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 44
Dependent Claim
47 words
The method as recited by claim 34 wherein said time period Beta1 is limited by the constraint: Beta1>(2*Tau.sub.p)+Tau.sub.m and, where Tau p is representative of a physical propagation of said medium and Tau m is representative of a detection and turnaround delay characteristic of said first device.
Claim 45
Independent Claim
245 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, said network comprising a first device and a second device, comprising the steps of: a) said first device preparing a first message packet for transmission on said medium, said first message packet being classified as either a priority message packet or a non-priority message packet, independent of said second device said first device being preassigned a priority slot, and message packets classified as priority are communicated onto said medium during said priority slot; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F including as a factor a pseudo-random delay factor T, said pseudo-random delay factor T calculated including a backlog factor BL, said backlog factor BL is based on the estimated backlog of messages for transmission on said medium and said backlog factor BL is in the range of (N+1) . . . (N+1+(w base *BL) where: N is the number of said priority slots; and w base is a predetermined number of priority slots S; e) said first device continuing to monitor said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 46
Independent Claim
245 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, said network comprising a first device and a second device, comprising the steps of: a) said first device preparing a first message packet for transmission on said medium, said first message packet being classified as either a priority message packet or a non-priority message packet, independent of said second device said first device being preassigned a priority slot, and message packets classified as priority are communicated onto said medium during said priority slot; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F including as a factor a pseudo-random delay factor T, said pseudo-random delay factor T calculated including a backlog factor BL, said backlog factor BL is based on the estimated backlog of messages for transmission on said medium and said backlog factor BL is in the range of (N+1) . . . (N+1+(w base *BL) where: N is the number of said priority slots; and w base is a predetermined number of priority slots S; e) said first device continuing to monitor said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 47
Dependent Claim
14 words
The method as recited by claim 37 wherein w base is equal to 16.
Claim 48
Independent Claim
200 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F varying depending on a backlog factor BL, said backlog factor BL based on the backlog of messages for transmission on said medium, said backlog factor BL being incremented each time a message packet is received or transmitted by said first device, said backlog factor BL being incremented by an estimate of the number of messages to be generated responsive to a received message packet, said backlog factor BL being decremented each time a busy cycle is detected on said medium by said first device; e) said first device continuing to monitor said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 49
Independent Claim
200 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F varying depending on a backlog factor BL, said backlog factor BL based on the backlog of messages for transmission on said medium, said backlog factor BL being incremented each time a message packet is received or transmitted by said first device, said backlog factor BL being incremented by an estimate of the number of messages to be generated responsive to a received message packet, said backlog factor BL being decremented each time a busy cycle is detected on said medium by said first device; e) said first device continuing to monitor said medium during said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle during said time period P.
Claim 50
Dependent Claim
29 words
The method as recited by claim 39 wherein said received message packet includes an estimate of the number of messages to be generated responsive to the received message packet.
Claim 51
Dependent Claim
160 words
In a network of devices, said network for facilitating sending and receiving of messages between said devices, said network comprising a medium for transmitting said messages, an improved method for managing message traffic on said medium comprising the steps of: (a) a first of said devices initiating said backlog counter BL to a first value at initialization of said network; (b) said first device monitoring said medium; (c) said first device preparing a message for transmission on said medium, said first device continuing to monitor said medium during said step (b); (d) said first device sensing said medium is idle; (e) said first device waiting a time period P after completing said step (c), said time period P calculated utilizing a backlog counter BL as a factor, said first device continuing to monitor said channel during said time period P; (f) said first device transmitting said message on said medium if said medium remains idle during said time period P.
Claim 52
Dependent Claim
160 words
In a network of devices, said network for facilitating sending and receiving of messages between said devices, said network comprising a medium for transmitting said messages, an improved method for managing message traffic on said medium comprising the steps of: (a) a first of said devices initiating said backlog counter BL to a first value at initialization of said network; (b) said first device monitoring said medium; (c) said first device preparing a message for transmission on said medium, said first device continuing to monitor said medium during said step (b); (d) said first device sensing said medium is idle; (e) said first device waiting a time period P after completing said step (c), said time period P calculated utilizing a backlog counter BL as a factor, said first device continuing to monitor said channel during said time period P; (f) said first device transmitting said message on said medium if said medium remains idle during said time period P.
Claim 53
Dependent Claim
166 words
In a network of devices, said network for facilitating sending and receiving of messages between said devices, said network comprising a medium for transmitting said messages, an improved method for managing message traffic on said medium comprising the steps of: (a) a first of said devices monitoring said medium; (b) said first device preparing a message for transmission on said medium, said first device continuing to monitor said medium during said step (b); (c) said first device sensing said medium is idle; (d) said first device waiting a time period P after completing said step (c), said time period P calculated utilizing a backlog counter BL as a factor, said first device continuing to monitor said channel during said time period P; (e) said first device incrementing said backlog counter BL based on information received by said first device detailing expected message transmissions on said medium; (f) said first device transmitting said message on said medium if said medium remains idle during said time period P.
Claim 54
Dependent Claim
166 words
In a network of devices, said network for facilitating sending and receiving of messages between said devices, said network comprising a medium for transmitting said messages, an improved method for managing message traffic on said medium comprising the steps of: (a) a first of said devices monitoring said medium; (b) said first device preparing a message for transmission on said medium, said first device continuing to monitor said medium during said step (b); (c) said first device sensing said medium is idle; (d) said first device waiting a time period P after completing said step (c), said time period P calculated utilizing a backlog counter BL as a factor, said first device continuing to monitor said channel during said time period P; (e) said first device incrementing said backlog counter BL based on information received by said first device detailing expected message transmissions on said medium; (f) said first device transmitting said message on said medium if said medium remains idle during said time period P.
Claim 55
Dependent Claim
47 words
The improvement as recited by claim 42 wherein said information detailing expected message transmissions a field N contained in the header of a transmitted message M, said field N designating a number of expected packets to be generated as a result of transmission of said message M.
Claim 56
Dependent Claim
28 words
The improvement as recited by claim 43 wherein said step of incrementing said backlog counter BL is not carried out where said backlog counter BL exceeds a threshold.
Claim 57
Dependent Claim
23 words
The improvement as recited by claim 44 wherein said threshold is less than or equal to the number of nodes on said network.
Claim 58
Dependent Claim
21 words
The improvement as recited by claim 45 wherein said backlog counter BL is adjusted periodically based on feedback from said network.
Claim 59
Independent Claim
176 words
A method of avoiding data collisions in a medium connecting a plurality of devices in a network, said network comprising a plurality of devices including a first and a second device; said first device being preassigned a priority slot n for communications of priority messages, and said second device being preassigned a priority slot m for communication of priority messages, where m is not equal to n, said method of avoiding collisions comprising the steps of: (a) said first device preparing a first message packet for transmission on said medium, said first message being a priority message, said first message having an indicator set to indicate said first message is a priority message; (b) said first device sensing said medium to determine if said medium is idle; (c) said first device sensing said medium is idle; (d) said first device continuing to monitor said medium for n-1 priority slots; (e) said first device communicating said message packet onto the medium during said priority slot n if said medium remains idle during priority slots 1 through n-1.
Claim 60
Independent Claim
176 words
A method of avoiding data collisions in a medium connecting a plurality of devices in a network, said network comprising a plurality of devices including a first and a second device; said first device being preassigned a priority slot n for communications of priority messages, and said second device being preassigned a priority slot m for communication of priority messages, where m is not equal to n, said method of avoiding collisions comprising the steps of: (a) said first device preparing a first message packet for transmission on said medium, said first message being a priority message, said first message having an indicator set to indicate said first message is a priority message; (b) said first device sensing said medium to determine if said medium is idle; (c) said first device sensing said medium is idle; (d) said first device continuing to monitor said medium for n-1 priority slots; (e) said first device communicating said message packet onto the medium during said priority slot n if said medium remains idle during priority slots 1 through n-1.
Claim 61
Independent Claim
150 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F including as a factor a pseudo-random delay factor T, said pseudo-random delay factor T representing an integer number of time slots S, said integer number of time slots S varying dependent on backlog of the network; e) said first device monitoring said medium after said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle after said time period P.
Claim 62
Independent Claim
150 words
A method for avoiding data collisions in a medium connecting a plurality of devices in a network, comprising the steps of: a) a first device preparing a first message packet for transmission on said medium; b) said first device sensing said medium to determine if said medium is idle; c) said first device sensing said medium is idle; d) said first device computing a time period P after detecting said medium is idle using a formula F, said formula F including as a factor a pseudo-random delay factor T, said pseudo-random delay factor T representing an integer number of time slots S, said integer number of time slots S varying dependent on backlog of the network; e) said first device monitoring said medium after said time period P; f) said first device transmitting said first message packet onto said medium if said medium remains idle after said time period P.
References Cited (Backward Citations)
US4063220A
Cited
US4426697A
Cited
US4332027A
Cited
US4523299A
Cited
US4623886A
Cited
US4561092A
Cited
US4630264A
Cited
US4692918A
Cited
US5042083A
Cited
US4809268A
Cited
US4979168A
Cited
US4918690A
Cited
US4882579A
Cited
US4891637A
Cited
US4875038A
Cited
US4823123A
Cited
US4947162A
Cited
US5038346A
Cited
US5053883A
Cited
US5029209A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-06-06 | 1997-12-06 | 1998-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-06-06 | 2001-12-06 | 2002-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-06-06 | 2005-12-06 | 2006-06-07 | $7700.00 | Window Closed / Lapsed |