Apparatus for flexibly allocating bandwidth for a point-to-point, serial, bidirectional communication path
First Claim
1. In a digital data communication system, having a switching granularity of "x" bps, comprising a plurality of point-to-point, serial, bidirectional data paths each having a bandwidth, wherein the bandwidth of at least a first data path is divided into "m" slots, the slots each being subdivided into "n" fragments where the bandwidth of each granularity x, each one of said plurality of data paths being for transporting data within said system in response to a request for bandwidth from at least one of a set of data path users and wherein the system further comprises user interface manager means that stores, identifies and transmits parameters associated with a given user'"'"'s bandwidth allocation request, andbandwidth allocation control means, coupled to a first end of said first data path and to said user interface manager means, for controlling allocation of data bandwidth to one or more of the m×
- n fragments of first data path bandwidth, comprising;
(a) bit map means comprising m×
n bit locations, each bit location corresponding to a different fragment on said first data path wherein each one of said m×
n bit locations is used for storing a binary bit which takes a value of ZERO for indicating that its corresponding fragment is available or a value of ONE for indicating that its corresponding fragment is in use and unavailable;
(b) allocation means for identifying available fragments on said first data path, in response to a particular data path user'"'"'s request for bandwidth allocation, as specified by parameters received from said user interface manager means, wherein said allocation means is capable of performing the allocation in accordance with any one of a plurality of predefined rules, each of which define the bandwidth allocation layout request and any constraints.
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Abstract
Methods and apparatus are set forth which provide for the allocation of bandwidth for point-to-point, serial, bidirectional communication paths in a digital switching system. Bandwidth allocation is performed at both ends of a path (e.g. T1 line, IML, etc.) and may take place in either direction. Furthermore, according to the preferred embodiment of the invention, the Bandwidth Allocation Facility (BAF) at each end of a given path allocates bandwidth in integer multiples of maximum switching system granularity. The BAF also supports the implementation of user requests for any one of a plurality of allocation and boundry rules. To minimize the probability of contention and out of band signalling between the BAF pair associated with a given path, a front-to-back search mechanism is assigned for one BAF of the pair, while the other BAF utilizes a back-to-front search mechanism. In this way contention occurs only when a path'"'"'s capacity nears exhaustion while uneven loading (one side of the path versus the other) is accommodated. Further yet, methods and apparatus are set forth which support rapid deallocation of bandwidth and status reporting.
34 Citations
29 Claims
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1. In a digital data communication system, having a switching granularity of "x" bps, comprising a plurality of point-to-point, serial, bidirectional data paths each having a bandwidth, wherein the bandwidth of at least a first data path is divided into "m" slots, the slots each being subdivided into "n" fragments where the bandwidth of each granularity x, each one of said plurality of data paths being for transporting data within said system in response to a request for bandwidth from at least one of a set of data path users and wherein the system further comprises user interface manager means that stores, identifies and transmits parameters associated with a given user'"'"'s bandwidth allocation request, and
bandwidth allocation control means, coupled to a first end of said first data path and to said user interface manager means, for controlling allocation of data bandwidth to one or more of the m× - n fragments of first data path bandwidth, comprising;
(a) bit map means comprising m×
n bit locations, each bit location corresponding to a different fragment on said first data path wherein each one of said m×
n bit locations is used for storing a binary bit which takes a value of ZERO for indicating that its corresponding fragment is available or a value of ONE for indicating that its corresponding fragment is in use and unavailable;(b) allocation means for identifying available fragments on said first data path, in response to a particular data path user'"'"'s request for bandwidth allocation, as specified by parameters received from said user interface manager means, wherein said allocation means is capable of performing the allocation in accordance with any one of a plurality of predefined rules, each of which define the bandwidth allocation layout request and any constraints. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- n fragments of first data path bandwidth, comprising;
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15. A method of allocating bandwidth on each of a plurality of data paths in a digital communication switching system that has a switching granularity of "x" bits per second, wherein each of said data paths has a bandwidth divided into "m" slots, the slots each being subdivided into "n" fragments where n is a function of x, comprising the steps of:
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(a) allocating bandwidth, via bandwidth allocation control means, in integer multiples of x bits per second in accordance with predefined allocation rules; (b) maintaining a bit map for each end of a given data path wherein each map has at least m×
n bit locations, each of said m×
n bits corresponding to a different fragment on the path for which the bit maps are being maintained and further wherein the state of each bit indicates whether a particular fragment is available;(c) allocating bandwidth from a given end of said given data path by identifying an available fragment on said line utilizing the bit map being maintained for the given end of the data path; and (d) changing the state of the bit associated with the available fragment being allocated to thereby record that the fragment has been placed into use. - View Dependent Claims (16, 17, 18)
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19. Apparatus for allocating bandwidth in a digital switching system having a switching granularity of "x" bits per second, wherein said digital switching system further comprises a plurality of point-to-point, serial, bidirectional data paths each having a bandwidth, wherein the bandwidth of at least a first data path is divided into a plurality of slots each of which is further subdivided into a plurality of fragments, wherein the bandwidth of each of said plurality of fragments is chosen as a function of said switching granularity, each one of said plurality of data paths being for transporting data within said system in response to a request for bandwidth from at least one of a set of data path users, comprising:
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(a) means for inputting a set of bandwidth allocation parameters to bandwidth allocation control means; (b) bandwidth allocation control means, coupled to said means for inputting, for allocating bandwidth as function of said switching granularity ("x" bits per second) in accordance with predetermined allocation rules wherein a particular one of said rules may be specified by a given one of said parameters; and (c) user interface manager means, included in said digital switching system, for storing, identifying and transmitting parameters associated with a given user'"'"'s bandwidth allocation request, wherein said bandwidth allocation control means is coupled to a first end of said first data path and to said user interface manager means, for controlling allocation of data bandwidth to one or more of said plurality fragments of first data path bandwidth. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification