Dynamic bandwidth throttling

• US 8,966,110 B2
• Filed: 09/09/2010
• Issued: 02/24/2015
• Est. Priority Date: 09/14/2009
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Lippincott, Lisa Ellen, Lincroft, Peter James, Goodrow, Dennis Sidney
• Primary Examiner(s): Mejia, Anthony
• Application Number:
  US12/878,881
• Publication Number:
  US 20110066752A1
• Time in Patent Office: 1,629 Days
• Field of Search: 709/223, 709/224, 709/233
• US Class Current: 709/233
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 43/0894 Packet rate
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04L 45/122 by minimising distances, e.g. by selecting a route with minimum of number of hops
• CPC Class Codes: H04L 45/64 using an overlay routing layer
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions

Abstract

An approximation of the bandwidth of the narrowest link in a network is determined by watching how fast data gets to the other end and then back again. The rate of data transmission is limited according to this approximation. Dynamic capacity of the link, i.e. the amount of data that can be in-flight at the same time, neglecting any buffers, is also tracked. The technique looks at how much data is in-flight and, if there is more data in flight than the dynamic capacity of the network, the data transmission rate is slowed down.

Claims

1. A computer implemented method for dynamic bandwidth throttling, comprising:

recording, by a sender computer, transit times for packets in a network connection between the sender computer and a receiver computer over a predetermined period of time;

determining, by the sender computer, a baseline transit time value based on the recorded transit times;

recording, by the sender computer, a latest transit time for a packet sent to the receiver computer using the network connection;

determining, by the sender computer, a capacity metric and a lateness metric based on the latest transit time and the baseline transit time value;

determining, by the sender computer, a penalty based on the capacity metric and the lateness metric;

determining, by the sender computer, a delay time for a subsequent packet to be transmitted from the sender computer to the receiver computer using the network connection based on the penalty; and

delaying, by the sender computer, the subsequent packet according to the delay time to limit a rate of data transmission by the sender computer on the network connection.

2. The method of claim 1, further comprising:

adjusting the size of blocks of data transferred to optimize a transfer rate, wherein when blocks of data are received in their entirety, transmission of larger blocks is attempted; and

when blocks of data are received in different sizes than they were sent, smaller blocks are sent.

3. The method of claim 1, wherein the penalty comprises a compound penalty that combines an immediate penalty and the long-term penalty, wherein the immediate penalty represents an immediate debt the sender computer must pay before sending a next portion of data, wherein the immediate debt is paid in linear manner over time, wherein the long-term penalty comprises a long-term debt that is paid off in an exponentially decaying manner over time, and wherein determining the delay time comprises determining a time at which the immediate penalty and the long-term penalty are paid off.

4. The method of claim 1, further comprising:

determining said penalty based upon the following;

whether or not to send data based upon bandwidth;

trying to send data and failing because buffers on a local system are full;

another sender is sending data on a same system and a local system is unable to get data onto the network quickly enough;

stalling, where a receiver completely stops receiving data; and

when data arrives late, assigning a penalty for late arrival.

5. The method of claim 1, wherein recording transit times for packets in the network connection comprises:

sending a given packet having a sender timestamp to the receiver computer;

receiving, at a return time, a response packet having a receiver timestamp, wherein the receiver computer sends the response packet in response to receiving the given packet;

determining an outbound transit time based on the sender timestamp and the receiver timestamp; and

determining an inbound transit time based on the receiver timestamp and the return time.

6. The method of claim 1, comprising:

record transit times for packets in network connection between a sender computer and a receiver computer over a second period of time; and

updating the baseline transit time value based on the transit times recorded over and period of time.

7. The method of claim 3,

wherein determining the immediate penalty comprises dividing an amount of data to be sent in the subsequent packet by bandwidth to form an amount of time that is designated as a sending penalty.

8. The method of claim 7, wherein determine the delay time comprises:

determining the delay time, t, to wait before sending a next portion of data by solving the following equation;

9. The method of claim 8, wherein solving the equation comprises:

finding a value for t at which a first equation;

current_debt=immediate+long_term−

t

intersect with a second function;

10. The method of claim 1, further comprising providing parameters that can be used to control bandwidth, said parameters comprising any of:

a maximum control parameter that allows a user to set a maximum bandwidth to consume, wherein said parameter delays sending so that bandwidth use never exceeds said maximum;

a minimum control parameter that allows a user to set a minimum bandwidth to consume, wherein said attempts to not go below said minimum bandwidth, even if there is competing traffic;

or

a percentage control parameter that allows a user to set a percentage of bandwidth to consume, wherein said parameter delays sending to stay below a maximum percentage of available bandwidth, wherein if sending starts to interfere with said available bandwidth, sending is slowed down further, and wherein once competing traffic subsides, the sending is increased back up to said percentage.

11. A dynamic bandwidth throttling apparatus, comprising:

a processor; and

a memory coupled to the processor, wherein the memory comprises instructions which, when executed by the processor, cause the processor to;

record transit times for packets in a network connection between a sender computer and a receiver computer over a predetermined period of time;

determine a baseline transit time value based on the recorded transit times;

record a latest transit time for a packet sent to the receiver computer using the network connection;

determine a capacity metric and a lateness metric based on the latest transit time and the baseline transit time value;

determine a penalty based on the capacity metric and the lateness metric;

determine a delay time for a subsequent packet to be transmitted from the sender computer to the receiver computer using the network connection based on the penalty; and

delay the subsequent packet according to the delay time to limit a rate of data transmission by the sender computer on the network connection.

12. The apparatus of claim 11, said processor configured to provide parameters that can be used to control bandwidth, said parameters comprising any of:

a maximum control parameter that allows a user to set a maximum bandwidth to consume, wherein said parameter delays sending so that bandwidth use never exceeds said maximum;

a minimum control parameter that allows a user to set a minimum bandwidth to consume, wherein said attempts to not go below said minimum bandwidth, even if there is competing traffic;

or

a percentage control parameter that allows a user to set a percentage of bandwidth to consume, wherein said parameter delays sending to stay below a maximum percentage of available bandwidth, wherein if sending starts to interfere with said available bandwidth, sending is slowed down further, and wherein one competing traffic subsides, the sending is increased back up to said percentage.

13. The apparatus of claim 11, wherein the penalty comprises a compound penalty that combines an immediate penalty and the long-term penalty, wherein the immediate penalty represent an immediate debt the sender computer must pay before sending a next portion of data, wherein immediate debt is paid in a linear manner over time, wherein the long-term comprises a long-term debt that is paid off in an exponentially decaying manner over time, and wherein determining the delay time comprises determining a time at which the immediate penalty and the lone-term penalty are paid off.

14. The apparatus of claim 13, wherein determine the delay time comprises:

determining the delay time, t, to wait before sending a next portion of data by solving the following equation;

15. The apparatus claim 14, wherein solving the equation comprises:

finding a value for t at which a first equation;

current_debt=immediate+long_term−

t

intersects with a second function;

16. A computer program product comprising a non-transitory computer readable storage medium having a computer readable program stored therein, wherein the computer readable program, when executed on a computing device, causes the computing device to

record transit times for packets in a network connection between a sender computer and a receiver computer over a predetermined period of time;

determine a baseline transit time value based on the recorded transit times;

record a latest transit time for a packet sent to the receiver computer using the network connection;

determine a capacity metric and a lateness metric based on the latest transit time and the baseline transit time value;

determine a penalty based on the capacity metric and the lateness metric;

determine a delay time for a subsequent packet to be transmitted from the sender computer to the receiver computer using the network connection based on the penalty; and

delay the subsequent packet according to the delay time to limit a rate of data transmission by the sender computer on the network connection.

17. The computer program product of claim 16, wherein the computer readable program further causes the computing device to provide parameters that can be used to control bandwidth, said parameters comprising any of:

a maximum control parameter that allows a user to set a maximum bandwidth to consume, wherein said parameter delays sending so that bandwidth use never exceeds said maximum;

a minimum control parameter that allows a user to set a minimum bandwidth to consume, wherein said attempts to not go below said minimum bandwidth, even if there is competing traffic;

or

a percentage control parameter that allows a user to set a percentage of bandwidth to consume, wherein said parameter delays sending to stay below a maximum percentage of available bandwidth, wherein if sending starts to interfere with said available bandwidth, sending is slowed down further, and wherein once competing traffic subsides, the sending is increased back up to said percentage.

18. The computer program product of claim 16, wherein the penalty comprises a compound penalty that combines an immediate penalty and the long-term penalty, wherein the immediate penalty represents an immediate debt the sender computer must pay before sending a next portion of data, wherein the immediate debt is paid in a linear manner over lime, wherein the long-term penalty comprises a long-term debt that is paid off in an exponentially decaying manner over time, and wherein determining the delay time comprises determining a time at which the immediate penalty and the long-term penalty are paid off.

19. The computer program product of claim 18, wherein determine the delay time comprises:

determining the delay time, t, to wait before sending a next portion of data by solving the following equation;

20. The computer program product of claim 19, wherein solving the equation comprises:

finding a value for t at which a first equation;

current_debt=immediate+long_term−

t

intersects with a second function;