Bandwidth allocation system of virtual path in communication network of asynchronous transfer mode

• US 6,542,467 B2
• Filed: 03/04/1999
• Issued: 04/01/2003
• Est. Priority Date: 03/05/1998
• Status: Expired due to Fees

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: NEC Corporation
• Inventors: Umayabashi, Masaki
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): SCHULTZ, WILLIAM C
• Application Number:
  US09/262,338
• Publication Number:
  US 20030026290A1
• Time in Patent Office: 1,489 Days
• Field of Search: 370/230, 370/235, 370/233, 370/232, 370/389, 370/397, 370/399, 370/231, 709/247, 709/249
• US Class Current: 370/236
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/5632 Bandwidth allocation
• CPC Class Codes: H04L 2012/5682 Threshold; Watermark
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 49/255 Control mechanisms for ATM switching fabrics

Abstract

A node in an asynchronous transfer mode exchange network comprises a bandwidth monitor circuit for calculating a bandwidth used for a virtual path by measuring a cell amount entered into each virtual path, cell stored buffers for respectively storing an input cell for every virtual path, a bandwidth allocation control circuit for deciding a bandwidth allocation ratio, in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for every virtual path from the bandwidth monitor circuit, depending on a change of the Queue length in a cell within the cell stored buffer, and an output bandwidth control circuit for controlling output of the respective cell stored buffers, in accordance with the bandwidth allocation ratio decided by the bandwidth allocation control circuit.

Claims

1. A bandwidth allocation system of a virtual path for allocating bandwidths for a plurality of virtual paths in a communication network of asynchronous transfer mode, wherein a node in said asynchronous transfer mode network comprises:

bandwidth monitor means for calculating a bandwidth used for a virtual path by measuring a cell amount entered into each virtual path;

cell storing means for storing an input cell for each of said plurality of virtual paths;

bandwidth allocation control means for determining a bandwidth allocation ratio for output bandwidths in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor means in accordance with a change of the Queue length in the cell stored within said cell storing means; and

output bandwidth control means for controlling output of said respective cell storing means, in accordance with the bandwidth allocation ratio determined by said bandwidth allocation control means.

2. The bandwidth allocation system of claim 1, wherein said bandwidth allocation control means allocates an output bandwidth substantially greater than a used bandwidth with respect to said cell storing means if the increasing Queue length of the cell exceeds a predetermined value.

3. The bandwidth allocation system of a virtual path as set forth in claim 1, wherein an upper threshold of cell storing amount in said cell storing means is established, and

said bandwidth allocation control means, referring to a bandwidth used for each virtual path from said bandwidth monitor means, determines a bandwidth allocation ratio of output bandwidths with a weight added thereto according to the used bandwidth ratio, when the Queue length of a cell within said cell storing means exceeds the upper threshold.

4. The bandwidth allocation system of claim 1, wherein an upper threshold of cell storing amount in said cell storing means is established, and said bandwidth allocation control means:

comprises Queue length upper threshold excess detecting means, monitoring the Queue length of a cell within said cell storing means, for supplying a detection signal when the increasing Queue length exceeds the upper threshold; and

determines a bandwidth allocation ratio of output bandwidths with a weight added thereto according to a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor means, in response to the detection signal from said Queue length upper threshold excess detecting means.

5. The bandwidth allocation system of claim 1, wherein said bandwidth allocation control means allocates an output bandwidth substantially greater than a used bandwidth with respect to said cell storing means in which the increasing Queue length exceeds a predetermined value, and after providing said above-mentioned cell storing means with said substantially greater output bandwidth, surplus bandwidth allocation to said cell storing means is released when the Queue length of the cell in said cell storing means is reduced to a predetermined value.

15. The bandwidth allocation system of claim 1, wherein said bandwidth allocation control means comprises a state control buffer coupled between a queue length upper threshold excess detecting circuit and a queue length lower threshold arrival detecting circuit.

16. The bandwidth allocation system of claim 15, wherein said state control buffer comprises a state control table that stores information of a cell stored buffer identifier describing unit, a cell stored buffer state registering unit, and a cell stored buffer output bandwidth control unit.

6. A bandwidth allocation system of a virtual path for allocating bandwidths for a plurality of virtual paths in a communication network of asynchronous transfer mode, wherein a node in said asynchronous transfer mode network comprises:

bandwidth monitor means for calculating a bandwidth used for a virtual path by measuring a cell amount entered into each virtual path;

cell storing means for storing an input cell for each of said plurality of virtual paths;

bandwidth allocation control means for determining a bandwidth allocation ratio for output bandwidths in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor means depending on a change of the Queue length in the cell stored within said cell storing means, and

output bandwidth control means for controlling output of said respective cell storing means, in accordance with the bandwidth allocation ratio determined by said bandwidth allocation control means;

an upper threshold and a lower threshold of a cell storing amount in said cell storing means; and

wherein

said bandwidth allocation control means includes,

bandwidth weight allocation control means for determining a bandwidth allocation ratio of output bandwidths, with weight added thereto according to a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor means, when the Queue length of a cell stored within said cell storing means exceeds the upper threshold, and

bandwidth ratio allocation control means, after decision of the bandwidth allocation ratio by said bandwidth weight allocation control means and output control of said respective cell storing means by said output bandwidth control means, for determining a bandwidth allocation ratio of output bandwidths in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor means, when the Queue length arrives at the lower threshold.

7. The bandwidth allocation system of claim 6, wherein said bandwidth allocation control means includes:

Queue length upper threshold excess detecting means, monitoring the Queue length of a cell stored within said cell storing means, for supplying a detection signal when the increasing Queue length exceeds the upper threshold;

bandwidth weight allocation control means for determining a bandwidth allocation ratio of output bandwidths, with weight added thereto according to a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor means, in response to the detection signal from said Queue length upper threshold excess detecting means;

Queue length lower threshold arrival detecting means, monitoring the Queue length of a cell stored within said cell storing means, for supplying a detection signal when the Queue length is reduced to the lower threshold, after determination of the bandwidth allocation ratio by said bandwidth weight allocation control means and output control of said respective cell storing means by said output bandwidth control means; and

bandwidth ratio allocation control means for determining a bandwidth allocation ratio of output bandwidths in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor means, in response to the detection signal from said Queue length lower threshold arrival detecting means.

8. The bandwidth allocation system of claim 6, wherein said bandwidth allocation control means includes:

Queue length upper threshold excess detecting means, monitoring the Queue length of a cell stored within said cell storing means, for supplying a detection signal when the increasing Queue length exceeds the upper threshold;

bandwidth weight allocation control means for determining a bandwidth allocation ratio of output bandwidths, with weight added thereto according to a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor means, in response to the detection signal from said Queue length upper threshold excess detecting means;

Queue length lower threshold arrival detecting means, monitoring the Queue length of a cell stored within said cell storing means, for supplying a detection signal when the Queue length is reduced to the lower threshold, after determination of the bandwidth allocation ratio by said bandwidth weight allocation control means and output control of said respective cell storing means by said output bandwidth control means;

bandwidth ratio allocation control means for determining a bandwidth allocation ratio of output bandwidths in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor means, in response to the detection signal from said Queue length lower threshold arrival detecting means, and further comprising state control means for controlling a state of the Queue length of a cell within said cell storing means, the state of said cell storing means controller by said state control means is changed according to the detection results of said Queue length upper threshold excess detecting means and said Queue length lower threshold arrival detecting means; and

said bandwidth weight allocation control means and said bandwidth ratio allocation control means judge whether determination processing of a bandwidth allocation ratio should be performed, with reference to the state of said cell storing means controlled by said state control means.

9. The bandwidth allocation system of claim 8, wherein said state control means stores identification information for identifying said cell storing means, information indicating whether the Queue length is reduced to the lower threshold after being equal to the upper threshold, in every identification information, and information indicating an output bandwidth.

17. The bandwidth allocation system of claim 6, wherein said bandwidth allocation control means comprises a state control buffer coupled between said queue length upper threshold excess detecting means and a queue length lower threshold arrival detecting means.

18. The bandwidth allocation system of claim 17, wherein said state control buffer comprises a state control table that stores information of a cell stored buffer identifier describing unit, a cell stored buffer slate registering unit, and a cell stored buffer output bandwidth control unit.

10. A bandwidth allocation system of a virtual path that allocates bandwidths for a plurality of virtual paths in a communication network of asynchronous transfer mode, wherein a node in the asynchronous transfer mode network comprises:

a bandwidth monitor that calculates a bandwidth used for a virtual path by measuring a cell amount entered into each virtual path;

a cell stored buffer that stores an input cell for each of said plurality of virtual paths;

a bandwidth allocation control circuit that determines a bandwidth allocation ratio for output bandwidths in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor depending on a change of the Queue length in the cell stored within said cell stored buffer; and

an output bandwidth control circuit that controls output of said respective cell stored buffers, in accordance with the bandwidth allocation ratio decided by said bandwidth allocation control circuit.

11. The bandwidth allocation system of claim 10, wherein an upper threshold of a cell storing amount in said cell stored buffer is established, and

said bandwidth allocation control circuit decides a bandwidth allocation ratio of output bandwidths, with weight added thereto according to a used bandwidth ratio obtained by reference to each bandwidth used for each of said plurality of virtual paths from said bandwidth monitor, when the Queue length of a cell stored within said cell stored buffer exceeds the upper threshold.

19. The bandwidth allocation system of claim 10, wherein said bandwidth allocation control circuit comprises a state control buffer coupled between a queue length upper threshold excess detecting circuit and a queue long lower threshold arrival detecting circuit.

20. The bandwidth allocation system of claim 19, wherein said state control buffer comprises a state control table that stores information of a cell stored buffer identifier describing unit, a cell stored buffer state registering unit, and a cell stored buffer output bandwidth control unit.

12. A method of allocating bandwidth in an asynchronous transfer mode, comprising:

(a) accessing current bandwidth information of a plurality of virtual paths in response to a first control signal;

(b) determining a bandwidth allocation ratio in accordance with a queue length of one of said plurality of virtual paths, wherein a bandwidth is weighted when said queue length exceeds a first threshold;

(c) calculating corresponding output bandwidths for said cell stored buffers in accordance with said bandwidth allocation ratio; and

(d) generating said first control signal in accordance with said output bandwidths.

13. The method of claim 12, further comprising:

(e) detecting a state when said queue length is reduced to a second threshold;

(f) referring to a state control table in accordance with (e);

(g) changing a state of said one of said plurality of cell stored buffers;

(h) generating a second control signal in response to (g); and

(i) releasing a surplus of output bandwidth in accordance with said second control signal.

14. The method of claim 12, where said bandwidth is weighted by multiplying current bandwidth by a parameter greater than one to increase available bandwidth to said cell stored buffer.