EP0430571B1
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Dynamic window sizing in a data network
Assignee: AT&T Inc
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Filing: 1990-11-21
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Granted: 1996-03-06
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Expires: 2010-11-21
Abstract
No abstract record available.
Inventors
- 👤 Ellen Louise Hahne
- 👤 Samuel P. Morgan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 10:48
CPC Classifications
H; H04; H04L; H04L47/00; H04L47/10; H04L47/17; H04L47/16; H04L47/27; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L2012/5629; H04L2012/5631; H04L2012/5632; H04L2012/5634; H04L2012/5635; H04L2012/5678; H04L2012/5681; H04L47/33
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
100 words
A method used in a virtual circuit data network having one or more nodes to dyamically determine a window size W k-1 in the node for the kth virtual circuit using a given link from the node, the method being characterized by the steps of: determining the average number of active virtual circuits J k-1 using the link prior to the addition of the kth virtual circuit; and determining the window size W k-1 for the kth virtual circuit from the equation W k-1 W 0 = 1 J k-1 +1 , where W₀ is a full-speed round trip window.
Claim 2
Dependent Claim
69 words
The method set forth in claim 1 wherein: a virtual circuit in intermittent use has an average service time requirement τ in which it is in active use and an average idle time of hτ and the step of determining the average number of active virtual circuits J k-1 is performed using the recurrence J k-1 +1 J k-1 +1+h = J k k starting from J₀ = 0.
Claim 3
Dependent Claim
66 words
The method set forth in claim 1 wherein: a virtual circuit in intermittent use has an average service time requirement τ in which it is in active use and an average idle time of hτ and the step of determining the average number of active virtual circuits J k-1 is performed using the approximation k-h+ k-h 2 +4h 1/2 -2 2 for J k-1 .
Claim 4
Dependent Claim
48 words
The method set forth in claim 3 wherein: the step of determining the average number of active virtual circuits is performed using the longest round trip time of the network as τ and a value of h such that hτ is less than or equal to 10 seconds.
Claim 5
Independent Claim
186 words
A method used in a virtual circuit data network having one or more nodes to dynamically determine a window size W k-1 in the node for the kth virtual circuit using a given link from the node, the method characterized the steps of: determining that there is to be a fixed number M of window sizes; dividing the number N of virtual circuits which can exist simultaneously in the network into a set of M+1 break points such that 0 = N₀ < N₁ < ... <N M = N; associating M window sizes W₀ > W₁ > ... > W M-1 with the break points N₀ through N M-1 such that N i is associated with W i ; determining the average number of active virtual circuits J N i using the link prior to the addition of the kth virtual circuit; and determining the window size W i associated with virtual circuit N i from the equation W i W 0 = 1 J N i +1 where N i < k ≤ N i+1 and W₀ is a full-speed round trip window.
Claim 6
Dependent Claim
81 words
The method set forth in claim 5 wherein: a virtual circuit in intermittent use has an average service time requirement τ in which it is in active use and an average idle time of hτ and the step of determining the average number of active virtual circuits J N i is performed using the recurrence J k-1 +1 J k-1 +1+h = J k k starting from J₀ = 0 and retaining the result only for each J N i .
Claim 7
Dependent Claim
73 words
The method set forth in claim 5 wherein: a virtual circuit in intermittent use has an average service time requirement τ in which it is in active use and an average idle time of hτ and the step of determining the average number of active virtual circuits J N i is performed using the approximation N i +1-h+ N i +1-h 2 +4h 1 2 -2 2 for J N i .
Claim 8
Dependent Claim
48 words
The method set forth in claim 7 wherein the step of determining the average number of active virtual circuits is performed using the longest normal trip time of the network as τ and a value of h such that hτ is less than or equal to 10 seconds.
Claim 9
Dependent Claim
61 words
The method set forth in claim 8 wherein: the normalized total buffer usage b, where is minimized by solving the system of equations for k=1,2,...,M-1 (w k-1 - w k )dN k /dw k + N k+1 - N k = 0, where dN k /dw k = - 2hw k + N k + 1 - h w k .
Claim 10
Independent Claim
140 words
A method employed at an edge of a virtual circuit data network in which data is transported in cells to dynamically determine the size of the window to be requested in the network for a given virtual circuit originating at the edge, the method characterized by the steps of: keeping track of the total number of cells TC that the given virtual circuit has at the edge and in the network; keeping track of the cumulative throughput CT of cells of the given virtual circuit during a most recent renegotiation interval; and requesting a window for the virtual circuit in the network which is large enough to accommodate a number of cells which is the larger of TC and the product of CT times the quotient of the round-trip time divided by the length of the most recent renegotiation interval.
Claim 11
Dependent Claim
50 words
The method set forth in claim 10 further including the step of: keeping track of whether a cell buffer for the given virtual circuit at the edge overflows; and if the cell buffer overflows during the renegotiation interval, requesting a full round-trip window in the step of requesting a window.
Claim 12
Dependent Claim
69 words
The method set forth in claim 10 wherein: when the requested window is larger than the current window, the step of requesting a window may be performed at any time at which there is no pending request for a window; and when the requested window is smaller than the current window, the step of requesting a window may not be performed until the end of the current renegotiation interval.
Claim 13
Independent Claim
23 words
The method set forth in any of claims 10 through 12 wherein: the renegotiation interval is less than or equal to 10 seconds.
References Cited (Backward Citations)
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