US4901277A — Network data flow control technique

Claim 1

Independent Claim 90 words

A system for controlling the flow of data in a communication network of the kind in which a plurality of data streams are sent from an upstream node to a downstream node via a respective plurality of data paths carried on a link connected between said nodes, comprising means for said downstream node to specify information concerning permissible speeds of said data streams on the respective paths, and means for said upstream node to update the speeds of said plurality of data streams when necessary in response to said information.

Claim 2

Independent Claim 90 words

A system for controlling the flow of data in a communication network of the kind in which a plurality of data streams are sent from an upstream node to a downstream node via a respective plurality of data paths carried on a link connected between said nodes, comprising means for said downstream node to specify information concerning permissible speeds of said data streams on the respective paths, and means for said upstream node to update the speeds of said plurality of data streams when necessary in response to said information.

Claim 3

Dependent Claim 38 words

The system of claim 1 wherein said means to specify comprises means for considering when changes in said speeds will be specified by said downstream node, and means for identifying data paths whose speeds are to be changed.

Claim 4

Dependent Claim 53 words

The system of claim 2 wherein said means for identifying data paths comprise means for comparing the previously specified speed of each said path with an ideal speed for said path, and means for selecting a data path for a speed change based on said comparison and on said level of buffer utilization.

Claim 5

Dependent Claim 44 words

The system of claim 3 wherein said buffer means comprises a plurality of buffers allocated to respective said paths and said means for comparison further bases said ideal speed on the level of buffer utilization of said buffers allocated to a given said path.

Claim 6

Dependent Claim 24 words

The system of claim 4 wherein said ideal speed is reduced when the level of buffer utilization of said allocated buffers exceeds a maximum.

Claim 7

Dependent Claim 27 words

The system of claim 5 wherein said maximum comprises said allocated buffers containing two seconds worth of data bytes at said ideal speed prior to said reduction.

Claim 8

Dependent Claim 37 words

The system of claim 3 wherein said comparison is a ratio and said path is selected for a speed change if said ratio exceeds a threshold that varies with the level of buffer utilization of said buffer.

Claim 9

Dependent Claim 13 words

The system of claim 7 wherein said threshold increases with higher utilization levels.

Claim 10

Dependent Claim 32 words

The system of claim 7 wherein there is one said threshold that never exceeds unity for speed decreases and a second said threshold that is never less than unity for speed increases.

Claim 11

Dependent Claim 30 words

The system of claim 3 wherein said means for specifying further comprises means for establishing a new speed equal to said ideal speed times a factor no smaller than unity.

Claim 12

Dependent Claim 28 words

The system of claim 3 wherein said factor depends on the level of buffer utilization and higher said factors are associated with lower said levels of buffer utilization.

Claim 13

Dependent Claim 40 words

The system of claim 3 wherein said means for comparing bases said ideal speed on the previous speed set for said path by a node further downstream from said downstream node and on the maximum bandwidth available for said path.

Claim 14

Dependent Claim 89 words

The system of claim 2 wherein said means for determining comprises means for deciding when increases in said speeds should be considered, said decision being based on a level of said buffer utilization and on the interval between a current time and a time when speed increases were previously considered, and means for deciding when decreases in said speeds should be considered, said decision being based on said level of buffer utilization and on the interval between a current time and a time when speed decreases were previously considered.

Claim 15

Dependent Claim 41 words

The system of claim 13 wherein increases or decreases, respectively, in said speed are considered when the corresponding interval is longer than a predetermined amount of time, the duration of which depends on the level of utilization of said buffer means.

Claim 16

Dependent Claim 59 words

The system of claim 14 wherein the duration of said predetermined amount of time for a higher level of buffer utilization in the case of the decision to consider speed increases is longer than the duration of said predetermined amount of time for a higher level of buffer utilization in the case of the decision to consider speed decreases.

Claim 17

Dependent Claim 37 words

The system of claim 2 wherein said means for considering bases said considering on a level of said buffer utilization and on the interval between a current time and a time when speed changes were previously considered.

Claim 18

Dependent Claim 52 words

The system of claim 1 wherein said information comprises the maximum average speeds of said data streams on the respective paths, and further comprising buffer means in said downstream node for temporarily storing said data streams, said maximum average speeds being specified based on the level of utilization of said buffer means.

Claim 19

Dependent Claim 38 words

The system of claim 17 wherein said buffer means comprises a plurality of buffers and said means to specify includes means for measuring said level of buffer utilization as a percentage of said buffers which are being used.

Claim 20

Dependent Claim 20 words

The system of claim 1 further comprising means for communicating said information from said downstream node to said upstream node.

Claim 21

Dependent Claim 21 words

The system of claim 1 wherein said information is the maximum average speeds of said data strams on the respective paths.

Claim 22

Independent Claim 146 words

A system for aiding the control of the flow of data in a communications network having more than two nodes interconnected by links that carry data paths, and in which a data stream is sent from an upstream node to a downstream node on a data path that spans possibly one or more intermediate nodes, comprising means for the downstream node and each of said intermediate nodes to specify to an immediately preceding node along said data path information concerning the permissible speed of the data stream on the portion of said path carried by the link from said immediately preceding node, and means for said immediately preceding node to update the speed of said data stream when necessary in response to said information, whereby the speed of said data stream on said data path is controlled distributively by said downstream node and said intermediate nodes.

Claim 23

Independent Claim 146 words

A system for aiding the control of the flow of data in a communications network having more than two nodes interconnected by links that carry data paths, and in which a data stream is sent from an upstream node to a downstream node on a data path that spans possibly one or more intermediate nodes, comprising means for the downstream node and each of said intermediate nodes to specify to an immediately preceding node along said data path information concerning the permissible speed of the data stream on the portion of said path carried by the link from said immediately preceding node, and means for said immediately preceding node to update the speed of said data stream when necessary in response to said information, whereby the speed of said data stream on said data path is controlled distributively by said downstream node and said intermediate nodes.

Claim 24

Independent Claim 76 words

A method for controlling the flow of data in a communications network of the kind in which a plurality of data streams are sent respectively via a plurality of data paths from an upstream node to a downstream node, comprising the downstream node specifying information concerning permissible speeds of said data streams on the respective paths, and said upstream node updating the speeds of said plurality of data streams when necessary in response to said information.

Claim 25

Independent Claim 76 words

A method for controlling the flow of data in a communications network of the kind in which a plurality of data streams are sent respectively via a plurality of data paths from an upstream node to a downstream node, comprising the downstream node specifying information concerning permissible speeds of said data streams on the respective paths, and said upstream node updating the speeds of said plurality of data streams when necessary in response to said information.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-02-12	1993-08-14	1994-02-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-02-12	1997-08-14	1998-02-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-02-12	2001-08-14	2002-02-13	$7700.00	Window Closed / Lapsed

Network data flow control technique

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