Fast dynamic measurement of bandwidth in a TCP network environment

• US 20050108420A1
• Filed: 12/17/2004
• Published: 05/19/2005
• Est. Priority Date: 08/09/2000
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Klemets, Anders E., del Val, David, Brown, Thomas B.
• Granted Patent: US 7,349,977 B2
• Time in Patent Office: Days
• US Class Current: 709/232
• CPC Class Codes: H04L 41/0896 Bandwidth or capacity management, i.e. automatically increasing or decreasing capacities flow or congestion control using dynamic resource allocation, e.g. in-call renegotiation, H04L47/76
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 43/087 Jitter
• CPC Class Codes: H04L 43/0888 Throughput
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/193 at the transport layer, e.g. TCP related
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures

Abstract

The fast dynamic measurement of bandwidth in a TCP network environment utilizes a single pair of packets to calculate bandwidth between two entities on a network (such as the Internet). This calculation is based upon the packet-pair technique. This bandwidth measurement is extremely quick. On its journey across a network, communication devices may delay the packet pairs. In particular, TCP networks have two algorithms designed to delay some packets with the goal of increasing the overall throughput of the network. However, these algorithms effectively delay a packet pair designed to measure bandwidth. Therefore, they distort the measurement. These algorithms are Nagle and Slow Start. The fast dynamic measurement of bandwidth implements countermeasures to overcome the delays imposed by these algorithms. Such countermeasures include disabling the application of the Nagle Algorithm; minimizing the buffering of packets by sending a “push” packet right after the packet pair; and avoiding the Slow Start Algorithm by priming it with a dummy packet.

Claims

1. A method for facilitating speedy communication of packets between entities on a network, the method comprising:

sending a delay-disable command;

sending a set of packets from a sending entity to a receiving entity,

wherein both sendings are performed at an application layer of a computer in accordance with an OSI model.

2. A method as recited in claim 1, wherein the set of packets consists of two packets sent back-to-back.

3. A method as recited in claim 1, wherein the set of packets consists of a first bandwidth-measurement packet and a second bandwidth-measurement packet, wherein the second packet is sent immediately after the first packet.

4. A method as recited in claim 1, wherein the network is TCP.

5. A method as recited in claim 1, wherein the delay-disable command disables the Nagle Algorithm on one or more communication devices on the network.

6. A method as recited in claim 1, wherein the delay-disable command is TCP_NODELAY.

7. A computer-readable medium having computer-executable instructions that, when executed by a computer, performs the method as recited in claim 1.

8. A method as recited in claim 1, wherein the delay-disable commend is sent by the receiving entity to the sending entity.

9. A method for facilitating bandwidth measurement between two entities on a network, the method comprising:

sending a delay-disable command;

sending a pair of bandwidth-measurement packets from a sending entity to a receiving entity;

receiving a bandwidth calculation based upon measurements related to just the pair of bandwidth-measurement packets and not based upon measurements using any other packets.

10. A method as recited in claim 9, wherein the delay-disable command is sent by the receiving entity to the sending entity.

11. A computer-readable medium having computer-executable instructions that, when executed by a computer, perform a method to facilitate speedy communication of packets between entities on a network, the method comprising:

sending a delay-disable command;

sending a set of packets from a sending entity to a receiving entity, wherein the set of packets consists of two packets sent back-to-back and wherein both sendings are performed at an application layer of the computer in accordance with an OSI model.

12. An apparatus comprising:

a processor;

a transmission-delay avoider operating at an application layer in accordance with an OSI model and executable on the processor to;

send a delay-disable command;

send a set of packets from a sending entity to a receiving entity, the set of packets consists of two packets sent back-to-back.

13. A modulated data signal having data fields encoded thereon transmitted over a communications channel, consisting of:

a first field including a delay-disable command;

a second field including a first bandwidth-measurement packet;

a third field including a second bandwidth-measurement packet.

14. A method for facilitating speedy communication of packets between entities on a communications network, the method comprising:

sending a delay-disable command to direct a disablement of a communications delay imposed by one or more communication devices on a communications network;

while the communications delay is disabled, sending a set of packets from a sending entity to a receiving entity, wherein the set of packets consists of two packets sent back-to-back.

15. A method as recited in claim 14, wherein the two packets include a first bandwidth-measurement packet and a second bandwidth-measurement packet, wherein the second packet is sent immediately after the first packet.

16. A method as recited in claim 14, wherein the network is TCP.

17. A method as recited in claim 14, wherein the delay-disable command disables the Nagle Algorithm on one or more communication devices on the network.

18. A method as recited in claim 14, wherein the delay-disable command is TCP_NODELAY.

19. A program module having computer-executable instructions that, when executed by a computer, performs the method as recited in claim 14 at an application layer in accordance with an OSI model.

20. A computer-readable medium having computer-executable instructions that, when executed by a computer, performs the method as recited in claim 14.