Determining the bandwidth of a communication link

Patent metadata

Field	Value
Publication number	US-11190430-B2
Application number	US-201716472427-A
Country	US
Kind code	B2
Filing date	Dec 13, 2017
Priority date	Dec 21, 2016
Publication date	Nov 30, 2021
Grant date	Nov 30, 2021

Abstract

A method of determining the bandwidth of a link carrying a plurality of data streams between a plurality of sources and a plurality of destinations in a network, the method including sending data packets from a first data stream over the link from one source to one destination at a first transmission rate, and measuring an associated first packet loss rate; sending further data packets from the first data stream over the link from the one source to the one destination at a second transmission rate, and measuring an associated second packet loss rate; and determining the bandwidth of the link in dependence on the first and second packet loss rates and the first and second transmission rates.

First claim

The invention claimed is:

1. A method of determining a bandwidth of a link carrying a plurality of data streams between a plurality of sources and a plurality of destinations in a network, the method comprising:
sending data packets from a first data stream over the link from one source to one destination at a first transmission rate, and measuring an associated first packet loss rate;
determining whether a sufficient number of data packets have been considered to determine a bandwidth of the link;
when the sufficient number of data packets have not been considered:
incrementing a data packet set index, and
selecting a second transmission rate based on the data packet set index;

sending further data packets from the first data stream over the link from the one source to the one destination at the second transmission rate, wherein the second transmission rate is different than the first transmission rate, and measuring an associated second packet loss rate, wherein the associated first packet loss rate is independent of the associated second packet loss rate; and
determining the bandwidth of the link in dependence on the first packet loss rate, the second packet loss rate, the first transmission rate, the second transmission rate.

2. The method as claimed in claim 1 , wherein the first data stream comprises a plurality of temporal segments, the data packets sent over the link at the first transmission rate are from a first temporal segment, and the data packets sent over the link at the second transmission rate are from a second temporal segment.

3. The method as claimed in claim 1 , wherein determining the bandwidth of the link comprises:
identifying a first expression for the bandwidth as a function of the first transmission rate and associated first packet loss rate;
identifying a second expression for the bandwidth as a function of the second transmission rate and associated second packet loss rate; and
determining the bandwidth of the link from the first identified expression and the second identified expression.

4. The method as claimed in claim 3 , wherein the first identified expression and the second identified expression of the bandwidths are further functions of a number of streams carried by the link.

5. The method as claimed in claim 3 , wherein the first expression of the bandwidth, B e1 , is given by

B

e
⁢

⁢
1

=

Tr
⁡

(
1
)

+

3

⁢

sN
s

R
⁢

2
⁢

PLR
⁡

(
1
)

,

and the second expression of the bandwidth, B e2 , is given by

B

e
⁢

⁢
2

=

Tr
⁡

(
2
)

+

3

⁢

sN
s

R
⁢

2
⁢

PLR
⁡

(
2
)

,

where Tr(1) is the first transmission rate, Tr(2) is the second transmission rate, PLR(1) is the first packet loss rate, PLR(2) is the second packet loss rate, s is a size of a packet, N s is a number of competing streams carried by the link and R is a round trip time.

6. The method as claimed in claim 1 , wherein the method further comprises controlling the transmission rate of the data packets of the first data stream to be no more than a specified amount of the determined bandwidth of the link.

7. The method as claimed in claim 1 , wherein the bandwidth of the link is determined in dependence only on the first packet loss rate, the second packet loss rate, the first transmission rate and the second transmission rate.

8. The method as claimed in claim 1 , wherein the method further comprises:
sending data packets from the first data stream over the link at three or more transmission rates, and measuring an associated packet loss rate for each of the three or more transmission rates; and
determining the bandwidth of the link in dependence on the three or more transmission rates and the associated packet loss rates.

9. The method as claimed in claim 8 , wherein the bandwidth of the link is determined from the three or more transmission rates and the associated packet loss rates using a method of least squares applied to expressions of bandwidth.

10. The method as claimed in claim 1 , wherein each of the plurality of data streams are TCP data streams.

11. The method as claimed in claim 1 , further comprising:
further determining whether a sufficient number of data packets have been considered to determine the bandwidth of the link; and
when a sufficient number of data packets have not been considered based on the further determining:
further incrementing the data packet set index, and
selecting a further transmission rate based on the data packet set index,

wherein determining the bandwidth of the link is further in dependence on the further transmission rate and the further packet loss rate.

12. The method as claimed in claim 1 , wherein the link carries a number of competing data streams, N, and the determining the bandwidth of the link is done without knowledge of N.

13.

Assignees

• British Telecomm

Inventors

• Nilsson Michael
• Appleby Stephen
• Humeida Yousif

Classifications

• H04L43/0841

  Round trip packet loss · CPC title

• H04L43/0888

  Throughput · CPC title

• H04N21/23805

  Controlling the feeding rate to the network, e.g. by controlling the video pump · CPC title

• H04L47/283

  in response to processing delays, e.g. caused by jitter or round trip time [RTT] · CPC title

• H04L47/28

  in relation to timing considerations · CPC title