US5475682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of regulating backpressure traffic in a packet switched network
Assignee: AT&T Inc
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Filing: 1994-06-10
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Granted: 1995-12-12
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Expires: 2014-06-10
Abstract
Abstract A method of regulating backpressure traffic in a packet switched network made up of a plurality of switching elements each having a local buffer memory identifies at least one switching element which succeeds at least one other switching element in a transmission path. The at least one succeeding switching element has a congested local buffer memory. A backpressure signal is transmitted to the at least one other switching element. Packets destined for the succeeding switching element are queued in the local buffer memory of the at least one other switching element. Next, it is determined when the occupancy of the local buffer memory for the other switching element has exceeded a predetermined threshold. In response to the exceeded predetermined threshold, the other switching element ignores the backpressure signal transmitted from the succeeding switching element and transmits the queued packets to the succeeding switching element.
Inventors
- 👤 Abhijit K. Choudhury
- 👤 Ellen L. Hahne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:31
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L12/5602; H04L2012/5619; H04L2012/5629; H04L2012/5631; H04L2012/5632; H04L2012/5635; H04L2012/5678; H04L2012/5681; H04L2012/5682
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
158 words
A method of regulating backpressure traffic in a packet switched network comprised of a plurality of switching elements, each switching element having a local buffer memory associated therewith, at least one of the switching elements succeeding at least one other switching element in a particular transmission path, said at least one succeeding switching element having a congested local buffer memory, the method comprising the steps of: the succeeding switching element generating a backpressure signal; transmitting the backpressure signal from the succeeding switching element to the at least one other switching element; queuing packets destined for the succeeding switching element in the local buffer memory of the at least one other switching element in response to the backpressure signal; determining when the occupancy of the local buffer memory for the other switching element has exceeded a predetermined threshold; and in response to exceeding the predetermined threshold, the other switching element transmitting the queued packets to the succeeding switching element.
Claim 2
Independent Claim
158 words
A method of regulating backpressure traffic in a packet switched network comprised of a plurality of switching elements, each switching element having a local buffer memory associated therewith, at least one of the switching elements succeeding at least one other switching element in a particular transmission path, said at least one succeeding switching element having a congested local buffer memory, the method comprising the steps of: the succeeding switching element generating a backpressure signal; transmitting the backpressure signal from the succeeding switching element to the at least one other switching element; queuing packets destined for the succeeding switching element in the local buffer memory of the at least one other switching element in response to the backpressure signal; determining when the occupancy of the local buffer memory for the other switching element has exceeded a predetermined threshold; and in response to exceeding the predetermined threshold, the other switching element transmitting the queued packets to the succeeding switching element.
Claim 3
Dependent Claim
63 words
The method according to claim 1 further comprising the step of: the succeeding switching element employing a local buffer memory management scheme which determines the manner in which the local buffer memory of the succeeding switching element is managed when the other switching element has transmitted the queued packets thereto and when the local buffer memory of the succeeding switching element is congested.
Claim 4
Dependent Claim
112 words
The method according to claim 2 wherein each local buffer memory is comprised of a plurality of individual queues, each queue transmitting packets to a particular output port, and the step of employing a local buffer memory management scheme further comprising the steps of: determining the lengths of each of the individual queues of the local buffer memory of the succeeding switching element; determining which individual queue within the local buffer memory of the succeeding switching element is the longest; and providing space for the data transmitted to the local buffer memory of the succeeding switching element by pushing a packet from the longest individual queue out of the local buffer memory.
Claim 5
Dependent Claim
16 words
The method according to claim 1 wherein the packet switched network is a multistage packet switch.
Claim 6
Dependent Claim
14 words
The method according to claim 4 wherein said switch is of a hierarchical design.
Claim 7
Dependent Claim
14 words
The method according to claim 4 wherein said switch is of a non-hierarchical design.
Claim 8
Dependent Claim
15 words
The method according to claim 1 wherein each transmission path within the network is acyclic.
Claim 9
Dependent Claim
16 words
The method according to claim 2 wherein the packet switched network is a multistage packet switch.
Claim 10
Dependent Claim
14 words
The method according to claim 8 wherein said switch is of a non-hierarchical design.
Claim 11
Dependent Claim
14 words
The method according to claim 8 wherein said switch is of a hierarchical design.
Claim 12
Dependent Claim
15 words
The method according to claim 3 wherein each transmission path within the network is acyclic.
Claim 13
Dependent Claim
13 words
The method according to claim 1 wherein said packets are of variable length.
Claim 14
Dependent Claim
12 words
The method according to claim 1 wherein said packets are fixed length.
Claim 15
Dependent Claim
58 words
The method according to claim 1 further comprising the step of: the other switching element employing a local buffer memory management scheme which determines the manner in which the local buffer memory of the other switching element is managed when the local buffer memory is congested as a result of queuing packets in response to the backpressure signal.
Claim 16
Dependent Claim
112 words
The method according to claim 14 wherein each local buffer memory is comprised of a plurality of individual queues, each queue transmitting packets to a particular output port, and the step of employing a local buffer memory management scheme further comprising the steps of: determining the lengths of each of the individual queues of the local buffer memory of the other switching element; determining which individual queue within the local buffer memory of the other switching element is the longest; and providing space for the data arriving to the local buffer memory of the other switching element by pushing a packet from the longest individual queue out of the local buffer memory.
Claim 17
Dependent Claim
16 words
The method according to claim 15 wherein the packet switched network is a multistage packet switch.
Claim 18
Dependent Claim
14 words
The method according to claim 16 wherein said switch is of a hierarchical design.
Claim 19
Dependent Claim
14 words
The method according to claim 16 wherein said switch is of a non-hierarchical design.
Claim 20
Dependent Claim
15 words
The method according to claim 15 wherein each transmission path within the network is acyclic.
Claim 21
Dependent Claim
81 words
A switching element for a packet switched network comprising: a local buffer memory; means for receiving a backpressure signal from a downstream switching element; means for queuing packets destined for the downstream switching element in the local buffer memory when the backpressure signal has been received therefrom; means for determining if the occupancy of the local buffer memory has exceeded a predetermined threshold; and means for transmitting the queued packets to the downstream element when the predetermined threshold has been exceeded.
Claim 22
Dependent Claim
81 words
A switching element for a packet switched network comprising: a local buffer memory; means for receiving a backpressure signal from a downstream switching element; means for queuing packets destined for the downstream switching element in the local buffer memory when the backpressure signal has been received therefrom; means for determining if the occupancy of the local buffer memory has exceeded a predetermined threshold; and means for transmitting the queued packets to the downstream element when the predetermined threshold has been exceeded.
References Cited (Backward Citations)
US5237565A
Cited
US5247513A
Cited
US5303232A
Cited
US5144619A
Cited
US5287346A
Cited
US5313454A
Cited
US5400329A
Cited
US5274642A
Cited
US5335224A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-12-11 | 1999-06-12 | 1999-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-11 | 2003-06-12 | 2003-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-11 | 2007-06-12 | 2007-12-12 | $7700.00 | Window Closed / Lapsed |