Fast dynamic measurement of bandwidth in a TCP network environment

• US 20050100014A1
• Filed: 12/17/2004
• Published: 05/12/2005
• 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 7,353,286 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• 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

1-1. A method as recited in claim 1 further comprising establishing a TCP connection between the sending entity to the receiving entity, wherein the establishing is just before the sending of the set of packets.

2-2. A method as recited in claim 1, wherein the flow-control function is the Slow Start Algorithm.

3-3. A program module having computer-executable instructions that, when executed by a computer, performs the method as recited in claim 1 at an application layer in accordance with an OSI model.

4-4. A computer-readable medium having computer-executable instructions that, when executed by a computer, performs the method as recited in claim 1.

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

sending a pair of bandwidth-measurement packets from a sending entity to a receiving entity, wherein a transmission delay between packets in the pair is intolerable;

immediately before, sending at least one “

priming”

packet to avoid a transmission delay between packets in the pair, wherein the delay is caused by flow-control functions of a communication device on the network.

6. A method as recited in claim 5 further comprising receiving a bandwidth calculation based upon measurements related to the pair of packets.

7. 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 set of packets from a sending entity to a receiving entity, wherein a transmission delay between packets in the set is intolerable;

immediately before, sending at least one “

priming”

packet to avoid a transmission delay between packets in the set, wherein the delay is caused by flow-control functions of a communication device on the network.

8. An apparatus comprising:

a processor;

a transmission-delay avoider executable on the processor to;

send a set of packets from a sending entity to a receiving entity, wherein a transmission delay between packets in the set is intolerable;

immediately before, send at least one “

priming”

packet to avoid a transmission delay between packets in the set, wherein the delay is caused by flow-control functions of a communication device on the network.

9. A modulated data signal having data fields encoded thereon transmitted over a communications channel, comprising:

a first field including a “

priming”

packet;

a second field including a first bandwidth-measurement packet;

a third field including a second bandwidth-measurement packet;

wherein the “

priming”

packet facilitates minimization of transmission delay between packets, wherein the delay is caused by flow-control functions of a communication device on the network.