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US5909443A
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ATM network congestion control system using explicit rate cell marking
Assignee: International Business Machines Corp
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Filing: 1997-01-03
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Granted: 1999-06-01
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Expires: 2017-01-03
Abstract
Abstract An explicit rate algorithm is disclosed for use in an end-to-end closed loop flow control algorithm for an ATM network which carries at least constant bit rate (CBR) traffic, variable bit rate (VBR) traffic and adjustable bit rate (ABR) traffic. The algorithm determines how much additional bandwidth is available for ABR traffic on an output link from a node and produces an explicit rate variable that can be forwarded to a source for the ABR traffic. Both the maximum and minimum bandwidths already reserved for all connections on the output link are determined. A single reserved bandwidth value is chosen within the range defined by the maximum and minimum reserved bandwidth values. The current utilization of the ABR input buffer for the node is also determined. The explicit rate variable is generated as a function of the link capacity, the reserved bandwidth value and the current utilization of the ABR input buffer. The explicit rate variable is written into a resource management cell which is routed through the network to the ABR traffic source. The explicit rate variable is intended to change the input rate of the ABR source to utilize more of the ABR input buffer.
Inventors
- 👤 Aline Fichou
- 👤 Serge Fdida
- 👤 Claude Galand
- 👤 Gerald Arnold Marin
- 👤 Raif O. Onvural
- 👤 Ken Van Vu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:59
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q11/0478; H04L; H04L12/00; H04L12/28; H04L12/54; H04L12/56; H04L12/5601; H04L2012/5629; H04L2012/5631; H04L2012/5632; H04L2012/5635
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
191 words
In a packet communications network including a plurality of nodes interconnected by transmission links, at least one of said nodes having at least one input buffer for temporarily storing packets delivered to the node, a flow control system for controlling the flow of packets on an output link from the node, said flow control system producing an explicit rate signal to be used to control the rate at which packets are provided to the node by a traffic source, said flow control system comprising: means for determining the bandwidth reserved for existing packet traffic on the output link; means for determining the unused capacity of an input buffer in which packets destined for the output link are temporarily stored; means for generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved, and the unused capacity of the input buffer; and means for forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which packets are provided to the network to more fully utilize the unused capacity of the input buffer.
Claim 2
Dependent Claim
191 words
In a packet communications network including a plurality of nodes interconnected by transmission links, at least one of said nodes having at least one input buffer for temporarily storing packets delivered to the node, a flow control system for controlling the flow of packets on an output link from the node, said flow control system producing an explicit rate signal to be used to control the rate at which packets are provided to the node by a traffic source, said flow control system comprising: means for determining the bandwidth reserved for existing packet traffic on the output link; means for determining the unused capacity of an input buffer in which packets destined for the output link are temporarily stored; means for generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved, and the unused capacity of the input buffer; and means for forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which packets are provided to the network to more fully utilize the unused capacity of the input buffer.
Claim 3
Dependent Claim
66 words
A flow control system as set forth in claim 1 wherein said reserved bandwidth determining means comprises: means for determining the maximum bandwidth reserved for existing packet traffic on the output link; means for determining the minimum bandwidth reserved for existing packet traffic on the output link; and means for selecting a reserved bandwidth value in the range limited by the maximum and minimum reserved bandwidth.
Claim 4
Dependent Claim
49 words
A flow control system as set forth in either of claims 1 or 2 wherein said means for forwarding an explicit rate parameter comprises: means for writing the parameter into a control cell; and means for forwarding the control cell into the network for delivery to the traffic source.
Claim 5
Dependent Claim
166 words
For use in a packet communications network including a plurality of nodes interconnected by transmission links, at least one of said nodes having an input buffer for temporarily storing packets delivered to the node, a flow control method for controlling the flow of packets on an output link from the node, said packets originating in a packet traffic source in the network, said method comprising the steps of: determining the amount of bandwidth reserved for existing packet traffic on the output link: determining the currently unused capacity of the input buffer; generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved for existing packet traffic on the output link and the currently unused capacity of the input buffer; and forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which packets enter the network to more fully utilize the unused capacity of the input buffer.
Claim 6
Dependent Claim
166 words
For use in a packet communications network including a plurality of nodes interconnected by transmission links, at least one of said nodes having an input buffer for temporarily storing packets delivered to the node, a flow control method for controlling the flow of packets on an output link from the node, said packets originating in a packet traffic source in the network, said method comprising the steps of: determining the amount of bandwidth reserved for existing packet traffic on the output link: determining the currently unused capacity of the input buffer; generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved for existing packet traffic on the output link and the currently unused capacity of the input buffer; and forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which packets enter the network to more fully utilize the unused capacity of the input buffer.
Claim 7
Dependent Claim
74 words
A method as set forth in claim 4 wherein the step of determining the amount of bandwidth reserved for existing packet traffic on the output link further comprises the steps of: determining the maximum bandwidth reserved for existing packet traffic on the output link; determining the minimum bandwidth reserved for existing packet traffic on the output link; selecting a reserved bandwidth value in the range limited by the maximum and minimum values of bandwidth.
Claim 8
Independent Claim
48 words
A method as set forth in either of claims 4 or 5 wherein the step of forwarding the explicit rate parameter further comprises the steps of: writing the explicit rate parameter into a control packet; sending the control packet through the network for delivery to the traffic source.
Claim 9
Dependent Claim
169 words
A packet communications network including a plurality of nodes, at least some of said nodes having input buffers for temporarily storing packets delivered to the nodes, a plurality of link interconnecting the nodes, and at least one flow control system for controlling the flow of packets on at least one of the nodes having an input buffer, said flow control system comprising: means for determining the bandwidth reserved for existing packet traffic on the output link; means for determining the unused capacity of the input buffer in which packets destined for the output link are temporarily stored; means for generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved, and the unused capacity of the input buffer; and means for forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which packets are provided to the network to more fully utilize the unused capacity of the input buffer.
Claim 10
Dependent Claim
169 words
A packet communications network including a plurality of nodes, at least some of said nodes having input buffers for temporarily storing packets delivered to the nodes, a plurality of link interconnecting the nodes, and at least one flow control system for controlling the flow of packets on at least one of the nodes having an input buffer, said flow control system comprising: means for determining the bandwidth reserved for existing packet traffic on the output link; means for determining the unused capacity of the input buffer in which packets destined for the output link are temporarily stored; means for generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved, and the unused capacity of the input buffer; and means for forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which packets are provided to the network to more fully utilize the unused capacity of the input buffer.
Claim 11
Dependent Claim
70 words
A packet communications network having a flow control system as defined in claim 7 wherein said reserved bandwidth determining means comprises: means for determining the maximum bandwidth reserved for existing packet traffic on the output link; means for determining the minimum bandwidth reserved for existing packet traffic on the output link; and means for selecting a reserved bandwidth value in the range limited by the maximum and minimum bandwidth reserved.
Claim 12
Dependent Claim
49 words
A flow control system as set forth in either of claims 7 or 8 wherein said means for forwarding an explicit rate parameter comprises: means for writing the parameter into a control cell; and means for forwarding the control cell into the network for delivery to the traffic source.
Claim 13
Dependent Claim
193 words
In an ATM packet communications network for carrying different classes of ATM traffic, including constant bit rate (CBR) traffic, variable bit rate (VBR) traffic and available bit rate (ABR) traffic, said network including a plurality of nodes interconnected by transmission links, at least one of said nodes having an input buffer for temporarily storing ATM packets delivered to the node, an explicit rate flow control system for controlling the flow of packets on an output tranmission link from the node, said flow control system comprising: means for determining the bandwidth reserved for existing packet traffic on the output link; means for determining the unused capacity of an input buffer in which packets destined for the output link are temporarily stored; means for generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved, and the unused capacity of the input buffer; and means for forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which ABR packets are provided to the network to more fully utilize the unused capacity of the input buffer.
Claim 14
Dependent Claim
193 words
In an ATM packet communications network for carrying different classes of ATM traffic, including constant bit rate (CBR) traffic, variable bit rate (VBR) traffic and available bit rate (ABR) traffic, said network including a plurality of nodes interconnected by transmission links, at least one of said nodes having an input buffer for temporarily storing ATM packets delivered to the node, an explicit rate flow control system for controlling the flow of packets on an output tranmission link from the node, said flow control system comprising: means for determining the bandwidth reserved for existing packet traffic on the output link; means for determining the unused capacity of an input buffer in which packets destined for the output link are temporarily stored; means for generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved, and the unused capacity of the input buffer; and means for forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which ABR packets are provided to the network to more fully utilize the unused capacity of the input buffer.
Claim 15
Dependent Claim
136 words
A flow control system as set forth in claim 10 wherein said reserved bandwidth determining means comprises: means for determinining the maximum bandwidth reserved for existing packet traffic on the output link, the maximum bandwidth reserved being determined by the total of reserved peak cell rates for existing CBR traffic, reserved equivalent capacities for existing VBR traffic and reserved minimum cell rates for existing ABR traffic; means for determining the minimum bandwidth reserved for existing packet traffic on the output link, the minimum bandwidth reserved being determined by the total of reserved peak cell rates for existing CBR traffic, reserved sustainable cell rates for existing VBR traffic and reserved minimum cell rates for existing ABR traffic; and means for selecting a single reserved bandwidth value in the range limited by the maximum and minimum bandwidth reserved.
Claim 16
Dependent Claim
48 words
A flow control system as set forth in claim 11 wherein said means for forwarding an explicit rate parameter comprises: means for writing the explicit rate parameter into a resource management cell; and means for forwarding the control cell into the network for delivery to the traffic source.
Claim 17
Dependent Claim
174 words
An article of manufacture comprising: a computer readable medium having computer readable program code embodied therein for controlling the flow of packets on an output link from a node in a packet communications network including a plurality of nodes interconnected by transmission links, said node having an input buffer for temporarily storing packets delivered to the node, the computer readable program code in said article of manufacture comprising code for determining the amount of bandwidth reserved for existing packet traffic on the output link, code for determining the currently unused capacity of the input buffer, code for generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved for existing packet traffic on the output link and the currently unused capacity of the input buffer, and code for forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which packets enter the network to more fully utilize the unused capacity of the input buffer.
Claim 18
Dependent Claim
174 words
An article of manufacture comprising: a computer readable medium having computer readable program code embodied therein for controlling the flow of packets on an output link from a node in a packet communications network including a plurality of nodes interconnected by transmission links, said node having an input buffer for temporarily storing packets delivered to the node, the computer readable program code in said article of manufacture comprising code for determining the amount of bandwidth reserved for existing packet traffic on the output link, code for determining the currently unused capacity of the input buffer, code for generating an explicit rate parameter having a value dependent upon the capacity of the output link, the amount of link bandwidth already reserved for existing packet traffic on the output link and the currently unused capacity of the input buffer, and code for forwarding the explicit rate parameter to the traffic source to enable the source to adjust the rate at which packets enter the network to more fully utilize the unused capacity of the input buffer.
Claim 19
Dependent Claim
79 words
An article of manufacture as set forth in claim 13 wherein the code for determining the amount of bandwidth reserved for existing packet traffic on the output link further comprises: code determining the maximum bandwidth reserved for existing packet traffic on the output link; code for determining the minimum bandwidth reserved for existing packet traffic on the output link; and code for selecting a reserved bandwidth value in the range limited by the maximum and minimum values of bandwidth.
References Cited (Backward Citations)
US5636212A
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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) | 2002-05-31 | 2002-11-30 | 2003-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-31 | 2006-11-30 | 2007-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-31 | 2010-11-30 | 2011-06-01 | $7700.00 | Window Closed / Lapsed |