PROVIDING DIFFERENT RATES TO DIFFERENT USERS OF A DOWNLOAD SERVICE

• US 20080215749A1
• Filed: 03/02/2007
• Published: 09/04/2008
• Est. Priority Date: 03/02/2007
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bala, Vasanth, Pacifici, Giovanni, Spreitzer, Michael J., Imhasly, Michel
• Granted Patent: US 8,250,227 B2
• Time in Patent Office: Days
• US Class Current: 709/233
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]
• CPC Class Codes: H04L 47/821 Prioritising resource allocation or reservation requests

Abstract

A system, computer program and method for transmitting requested data from a data source in response to data transmission requests from at least one electronic device according to differential rates of throughput. Data transmission requests are classified into one of a plurality of throughput classes, with each throughput class having an assigned rate of throughput. A proportion of data transmission requests to be processed from each throughput class is selected such that each data transmission request has a rate of throughput approximating the assigned rate of throughput of its class. The requested data is then sent from the data source to the electronic device.

Claims

1. A method for transmitting requested data from a data source in response to data transmission requests from at least one electronic device according to differential rates of throughput, the method comprising:

classifying the data transmission requests into one of a plurality of throughput classes, each of the plurality of throughput classes having an assigned rate of throughput;

selecting a proportion of data transmission requests to be processed from each throughput class such that each data transmission request has a rate of throughput approximating the assigned rate of throughput of its throughput class; and

sending the requested data from the data source to the electronic device.

2. The method of claim 1, wherein selecting the proportion of data transmission requests to be processed is performed in a weighted round-robin manner such that data transmission requests with higher rates of throughput are selected more often than data transmission requests with lower rates of throughput.

3. The method of claim 1, further comprising:

instantiating at least one requester for each of the selected data transmission requests, the requester configured to retrieve a defined quantity of data from the data source;

fetching the defined quantity of data by the requester from the data source;

queuing the requester;

dequeuing the requester after a defined period of time calculated to cause the rate of throughput to approximate the assigned rate of throughput for the data transmission request; and

iteratively repeating the fetching, queuing and dequeuing operations until the requested data is completely transmitted to the electronic device.

4. The method of claim 3, wherein the defined period of time exceeds, within a defined degree of statistical confidence, an actual round-trip response time between a client-side adapter and a middleware manager, wherein the client-side adapter is configured to receive the data request from the electronic device and the middleware manager is configured to control the response time of requests.

5. The method of claim 3, further comprising:

assigning a sequence number to each of the defined quantities of data;

storing each received defined quantity of data at a buffer position in a data buffer, the buffer position being based on the sequence number modulo the number of buffer positions available at the buffer; and

transmitting the defined quantity of data to the electronic device when at least two buffer positions containing the defined quantity of data are continuous.

6. The method of claim 5, further comprising suspending the requesting of defined quantities of data by the requesters when half of the data in the data buffer has not been transmitted.

7. The method of claim 1, further comprising:

instantiating a requester for the data transmission request;

adding the requester to one of a plurality of requester queues, each of the requester queues containing requesters for data transmission requests belonging to the same throughput class;

dequeuing the requester according to a weighted round robin algorithm;

retrieving a defined quantity of data by the dequeued requester;

transmitting the defined quantity of data to the electronic device; and

iteratively repeating the adding, dequeuing, retrieving and transmitting operations until the requested data is completely transmitted to the electronic device.

8. The method of claim 7, wherein the dequeuing the requesters comprises:

configuring a weight vector having a scalar value for each requester queue, the scalar value for each requester queue determined such that its proportion to the sum of all scalar values in the weight vector approximates the proportion of bandwidth made available to data transmission requests having the rate of throughput for the requester queue;

initializing a state vector to contain the same scalar values as the weight vector;

dequeuing a requester from a requester queue having a positive corresponding scalar value in the state vector;

decrementing the scalar value of the state vector for the requester queue accessed by the dequeuing operation; and

iteratively repeating the dequeuing and decrementing operations until all scalar values in the state vector are non-positive or until all requester queues for which the scalar value is positive are empty.

9. The method of claim 7, further comprising:

associating timestamps with the dequeued requesters, the timestamps representing the time requesters are dequeued from the requester queues; and

wherein requeuing requesters includes placing requesters into the requester queues in order according to their associated timestamps.

10. The method of claim 7, further comprising:

queuing data transmission requests when a maximum number of data transmission requests are being processed; and

dequeuing the data transmission requests according to their assigned rate of throughput using a weighted round robin algorithm.

11. A system for transmitting data at a defined rate of throughput in response to client data requests, the system comprising:

a client-side adapter configured to instantiate one or more requesters in response to a client data request, each requester configured to periodically request a defined quantity of data, store a received defined quantity of data and wait for a defined period of time, the defined period of time calculated to cause the rate of throughput for the client data request to approximate a defined value; and

a middleware manager configured to control a response time for the client data requests.

12. The system of claim 11, wherein the defined period of time includes a time factor which, within a desired degree of confidence, exceeds a response time between the client-side adapter and a middleware manager.

13. The system of claim 11, further comprising:

a data buffer configured to store received defined quantities of data from the requesters, the data buffer including a predetermined number of positions;

wherein each of the requesters includes a sequence number such that each received defined quantity of data from the requesters is positioned in the data buffer according to the sequence number modulo the predetermined number of positions in the data buffer; and

wherein the client-side adapter is configured to transmit data to the client only when at least two buffer positions containing the defined quantity of data are continuous.

14. The system of claim 13, wherein the client-side adapter is configured to suspend instantiating one or more requesters if half of the data buffer contains the defined quantities of data from the requesters.

15. A system for transmitting data in response to data requests from at least one client according to differential rates of throughput, the system comprising:

at least one requester associated with a data request, the data request assigned a rate of throughput, the requester configured to request a defined quantity of data from a server and transmit the defined quantity of data to the client;

one or more requester queues, each requester queue configured to contain requesters corresponding to data requests with a particular assigned rate of throughput;

a queue manager configured to instantiate the requester in response to the data request and to dequeue the requester from the requester queue according to a weighted round robin algorithm; and

wherein the requester, upon being dequeued, is configured to requeue itself within the requester queue if data subject to the data request are not completely transmitted.

16. The system of claim 15, wherein the system further comprises:

a weight vector having a scalar value for each requester queue, the scalar value for each requester queue determined such that its proportion to the sum of all scalar values in the weight vector approximates the proportion of a bandwidth made available to data requests having the rate of throughput for the requester queue;

a state vector configured to initially contain scalar values identical to those in the weight vector; and

wherein the queue manager is further configured to dequeue a requester from a requester queue with a positive scalar value in the state vector and decrement the scalar value for the requester queue accessed until all scalar values in the state vector are non-positive or until all requester queues for which the scalar value is positive are empty.

17. A computer program product for transmitting requested data from a data source in response to data transmission requests from at least one electronic device according to differential rates of throughput, the computer program product comprising a computer-readable medium embodying computer program code, the computer program code comprising computer executable instructions configured for:

classifying the data transmission requests into one of a plurality of throughput classes, each of the plurality of throughput classes having an assigned rate of throughput;

selecting a proportion of data transmission requests to be processed from each throughput class such that each data transmission request has a rate of throughput approximating the assigned rate of throughput of its throughput class; and

sending the requested data from the data source to the electronic device.

18. The computer program product of claim 17, wherein selecting the proportion of data transmission requests to be processed is performed in a weighted round-robin manner such that data transmission requests with higher rates of throughput are selected more often than data transmission requests with lower rates of throughput.

19. The computer program product of claim 17, further comprising computer executable instructions configured for:

instantiating at least one requester for each of the selected data transmission requests, the requester configured to retrieve a defined quantity of data from the data source;

fetching the defined quantity of data by the requester from the data source;

queuing the requester;

dequeuing the requester after a defined period of time calculated to cause the rate of throughput to approximate the assigned rate of throughput for the data transmission request; and

iteratively repeating the fetching, queuing and dequeuing operations until the requested data are completely transmitted to the electronic device.

20. The computer program product of claim 17, further comprising computer executable instructions configured for:

instantiating a requester for the data transmission request;

adding the requester to one of a plurality of requester queues, each of the requester queues containing requesters for data transmission requests belonging to the same throughput class;

dequeuing the requester according to a weighted round robin algorithm;

retrieving a defined quantity of data by the dequeued requester;

transmitting the defined quantity of data to the electronic device; and

iteratively repeating the adding, dequeuing, retrieving and transmitting until the requested data are completely transmitted to the electronic device.