Internet traffic analysis tool

• US 7,065,482 B2
• Filed: 05/17/2001
• Issued: 06/20/2006
• Est. Priority Date: 05/17/2001
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shorey, Rajeev, Khurana, Varun, Yadav, Vikas, Kamra, Abhinav, Kapila, Sundeep
• Primary Examiner(s): Dharia, Rupal
• Assistant Examiner(s): Taylor, Nicholas
• Application Number:
  US09/860,114
• Publication Number:
  US 20020174216A1
• Time in Patent Office: 1,860 Days
• Field of Search: 709/223, 709/224, 709/232, 703/2
• US Class Current: 709/224
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/026 using flow identification
• CPC Class Codes: H04L 43/062 related to network traffic
• CPC Class Codes: H04L 43/0829 Packet loss
• CPC Class Codes: H04L 43/0847 Transmission error
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 43/0882 Utilisation of link capacity
• CPC Class Codes: H04L 43/0888 Throughput
• CPC Class Codes: H04L 43/16 Threshold monitoring

Abstract

The present invention relates to a traffic analysis method and tool for a network based on TCP/IP or UDP/IP or a combination thereof comprising passive monitoring means at intermediate nodes of the network, and estimation means to determine a full set of network traffic metrics connected to said passive monitoring means.

The instant invention also provides a configured computer program product for carrying out the above method.

Claims

1. A traffic analysis tool for a network based on TCP/IP or UDP/IP or a combination thereof comprising:

passive monitoring means at intermediate nodes of the network,

estimation means to determine a full set of network traffic metrics connected to said passive monitoring means, and

modeling means for determining a pricing for different users of said network based on a utilization of network resources by said different users,

wherein said estimation means includes a mechanism for determining goodput by aggregating the number of bytes in all relevant packets received at the node in unit time and deducting from said aggregate the aggregate of the number of bytes in packets that arrive more than once in said unit time,

wherein said estimation means determines duplicate packets by a mechanism for identifying packets bearing the same packet number,

wherein said estimation means includes a mechanism for determining link utilization by calculating a ratio of the aggregate link throughput to the capacity of the link,

wherein said estimation means is based on an analysis of the correlation between sequence numbers of the monitored packets both for forward (data packets) and reverse (acknowledgement packets (‘

Acks’

)) packet streams,

wherein said estimation means includes a mechanism for determining retransmission by detecting retransmissions due to timeout or shrinking of transmission window by identifying when the transmission enters a slow start phase,

wherein the slow start phase is identified by means determining when the inter-packet time difference is greater than a defined multiple of the average inter-packet time difference, and

wherein said estimation means determines lost packets by a mechanism for identifying packets for which an additional packet bearing the same packet sequence number is received prior to the receipt of the ‘

ACK’ and

the time interval between the receipt of the second packet and the receipt of the ‘

ACK’

is comparable to the estimated round trip time.

2. The tool as claimed in claim 1, wherein said passive monitoring means comprises TCPdump, TCPanaly, Coral Reef, Windmill or any other similar means which makes a copy of the monitored packet and extracts information about the connection (source and destination address and port numbers) and the packet sequence number.

3. The tool as claimed in claim 1, wherein said full set of network traffic metrics includes any of:

goodput,

throughput,

link utilization,

fraction or percentage of lost packets,

number or fraction or percentage of retransmitted packets,

number of duplicate packets, and

round trip time.

4. The tool as claimed in claim 1, wherein said estimation means includes a mechanism for determining throughput by aggregating the number of bytes in all relevant packets received at the node in unit time.

5. The tool as claimed in claim 1, wherein said estimation means includes a mechanism for determining retransmission by:

maintaining a count of the number of ‘

Acks’

received for each transmitted packet, with an ‘

Ack’

count of 4 being indicative of a retransmission.

6. The tool as claimed in claim 3, wherein said estimation means determines round trip time by a mechanism for calculating the average time interval between the receipt of a packet and the receipt of its acknowledgement.

7. The tool as claimed in claim 1 applied to the packets pertaining to an individual connection.

8. The tool as claimed in claim 1 applied to packets pertaining to a selected set of connections or to the aggregate of all connections at the node.

9. A traffic analysis method for a network based on TCP/IP or UDP/IP or a combination thereof, said method comprising:

monitoring passively at intermediate nodes of the network,

estimating a full set of network traffic metrics, and

determining a pricing model for different users of said network based on a utilization of network resources by said different users,

wherein said estimation includes determining goodput by aggregating the number of bytes in all relevant packets received at the node in unit time and deducting from said aggregate the aggregate of the number of bytes in packets that arrive more than once in said unit time,

wherein said estimation determines duplicate packets for identifying packets bearing the same packet number,

wherein said estimation determines link utilization by calculating a ratio of the aggregate link throughput to the capacity of the link,

wherein said estimation is based on an analysis of the correlation between sequence numbers of the monitored packets both for forward (data packets) and reverse (acknowledgement packets (‘

Acks’

)) packet streams,

wherein said estimation includes determining retransmission by detecting retransmissions due to timeout or shrinking of transmission window by identifying when the transmission enters a slow start phase,

wherein the slow start phase is identified by determining when the inter-packet time difference is greater than a defined multiple of the average inter-packet time difference, and

wherein said estimation determines lost packets by a mechanism for identifying packets for which an additional packet bearing the same packet sequence number is received prior to the receipt of the ‘

ACK’ and

the time interval between the receipt of the second packet and the receipt of the ‘

ACK’

is comparable to the estimated round trip time.

10. The method as claimed in claim 9, wherein said passive monitoring is through any of TCPdump, TCPanaly, Coral Reef, Windmill or any other similar method which makes a copy of the monitored packet and extracts information about the connection (source and destination address and port numbers) and the packet sequence number.

11. The method as claimed in claim 9, wherein said full set of network traffic metrics includes any of:

goodput,

throughput,

link utilization,

fraction or percentage of lost packets,

number or fraction or percentage of retransmitted packets,

number of duplicate packets, and

round trip time.

12. The method as claimed in claim 9, wherein said estimation includes determining throughput by aggregating the number of bytes in all relevant packets received at the node in unit time.

13. The method as claimed in claim 9, wherein said estimation includes determining retransmission by:

maintaining a count of the number of ‘

Acks’

received for each transmitted packet, with an ‘

Ack’

count of 4 being indicative of a retransmission.

14. The method as claimed in claim 11, wherein said estimation determines round trip time for calculating the average time interval between the receipt of a packet and the receipt of its acknowledgement.

15. The method as claimed in claim 9 applied to the packets pertaining to an individual connection.

16. The method as claimed in claim 9 applied to packets pertaining to a selected set of connections or to the aggregate of all connections at the node.

17. A computer program product comprising computer readable program code stored on computer readable storage medium embodied therein for traffic analysis for a network based on TCP/IP or UDP/IP or a combination thereof comprising:

computer readable program code means configured for monitoring passively at intermediate nodes of the network,

computer readable program code means configured for estimating a full set of network traffic metrics, and

computer readable program code means configured for determining a pricing model for different users of said network based on a utilization of network resources by said different users,

wherein said computer readable program code means configured for estimating includes determining goodput by aggregating the number of bytes in all relevant packets received at the node in unit time and deducting from said aggregate the aggregate of the number of bytes in packets that arrive more than once in said unit time,

wherein said computer readable program code means configured for estimating determines duplicate packets by a mechanism for identifying packets bearing the same packet number,

wherein said computer readable program code means configured for estimating determines link utilization by calculating a ratio of the aggregate link throughput to the capacity of the link,

wherein said computer readable program code means configured for estimating is based on an analysis of the correlation between sequence numbers of the monitored packets both for forward (data packets) and reverse (acknowledgement packets (‘

Acks’

)) packet streams,

wherein said computer readable program code means configured for estimating includes determining retransmission by detecting retransmissions due to timeout or shrinking of transmission window by identifying when the transmission enters a slow start phase,

wherein the slow start phase is identified by determining when the inter-packet time difference is greater than a defined multiple of the average inter-packet time difference, and

wherein said computer readable program code means configured for estimating determines lost packets for identifying packets for which an additional packet bearing the same packet sequence number is received prior to the receipt of the ‘

ACK’ and

the time interval between the receipt of the second packet and the receipt of the ‘

ACK’

is comparable to the estimated round trip time.

18. The computer program product as claimed in claim 17, wherein said computer readable program code means configured for passive monitoring is through any of TCPdump, TCPanaly, Coral Reef, Windmill or any other similar means which makes a copy of the monitored packet and extracts information about the connection (source and destination address and port numbers) and the packet sequence number.

19. The computer program product as claimed in claim 17, wherein said full set of network traffic metrics includes any of:

goodput,

throughput,

link utilization,

fraction or percentage of lost packets,

number or fraction or percentage of retransmitted packets,

number of duplicate packets, and

round trip time.

20. The computer program product as claimed in claim 17, wherein said computer readable program code means configured for estimating includes determining throughput by aggregating the number of bytes in all relevant packets received at the node in unit time.

21. The computer program product as claimed in claim 17, wherein said computer readable program code means configured for estimating includes determining retransmission by:

maintaining a count of the number of ‘

Acks’

received for each transmitted packet, with an ‘

Ack’

count of 4 being indicative of a retransmission.

22. The computer program product as claimed in claim 19, wherein said computer readable program code means configured for estimating determines round trip time by a mechanism for calculating the average time interval between the receipt of a packet and the receipt of its acknowledgement.

23. The computer program product as claimed in claim 17 applied to the packets pertaining to an individual connection.

24. The computer program product as claimed in claim 17 applied to packets pertaining to a selected set of connections or to the aggregate of all connections at the node.