System and method for remotely estimating bandwidth between internet nodes

• US 20020133614A1
• Filed: 02/01/2001
• Published: 09/19/2002
• Est. Priority Date: 02/01/2001
• Status: Abandoned Application

• Current Assignee: Telcordia Technologies Incorporated (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Telcordia Technologies Incorporated (Telefonaktiebolaget LM Ericsson)
• Inventors: Spacek, Thomas, Kettenring, John, Ho, Yu-Yun K., Matija, Ricardo, Neidhardt, Arnold, Madhani, Sunil, Weerahandi, Samaradasa
• Application Number:
  US09/773,839
• Publication Number:
  US 20020133614A1
• Time in Patent Office: Days
• US Class Current: 709/237
• CPC Class Codes: H04L 41/142 using statistical or mathematical methods
• CPC Class Codes: H04L 43/0858 One way delays
• CPC Class Codes: H04L 43/0882 Utilisation of link capacity
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04L 43/50 Testing arrangements

Abstract

A communications network monitoring system and method remotely determines the total bandwidth between any two nodes on the network as well as the available bandwidth between nodes at a given time. A remote host sends data packets to each of the two nodes. A reply is sent back to the remote host generating a delay time. A set of delay times for data packets of various sizes is generated at the host. The data set is then analyzed using a robust estimation method and a Bayesian analysis to determine the total bandwidth and the mean delay between the two nodes. Moreover, the available bandwidth for a time, t, can be estimated by first injecting traffic into the network from a remote traffic generator to develop an estimate of the traffic and a router characteristic parameter, γ. This constant and a Bayesian estimate of the α(t) are used to estimate the available bandwidth at any given time t.

Claims

1. A method for estimating the total bandwidth between a first node and a second node in a communications network from a remote host comprising:

generating at the remote host a plurality of randomly-sized data packet pairs each having a first data packet and a second data packet of equivalent size;

sending from the remote host each of said first data packets to said first node;

sending from the remote host each of said second data packets to said second node;

receiving at the remote host a response message from each of said first and second nodes;

generating a set of first delay times indicative of the time each of said first data packets required to reach said first node based on the received response messages;

generating a set of second delay times indicative of the time each of said second data packets required to reach said second node based on the received response messages;

estimating the total bandwidth based on said set of first delay times and said second delay times.

estimating the total hop delay based on said set of first delay times and said second delay times.

2. The method of claim 1 wherein the steps of estimating the total bandwidth and hop delay further comprises the steps of generating a first estimate indicative of the total packet-size independent delay between said first node and said second node and a first estimate indicative of the delay per byte between said first node and said second node using a robust estimation method.

3. The method of claim 2 wherein the first estimate indicative of the total packet-size independent delay, {circumflex over (α

)}⁰, and the first estimate indicative of the delay per byte, {circumflex over (β

)}⁰, are generated according to a robust estimation method such as the least trimmed squares robust estimation method using the following relationship;

4. The method of claim 2 wherein the step of estimating total hop delay further comprises the step of generating a final estimate of the total packet-size independent delay based on a Bayesian analysis assuming that the first estimate indicative of the delay per byte is correct.

5. The method of claim 4 wherein the Bayesian point analysis further assumes a right-skewed distribution such as the inverse Gaussian delay distribution.

6. The method of claim 5 wherein the Bayesian point analysis for the final estimate of the total packet-size independent delay, α

, is determined according to the following relationship;

7. The method of claim 1 wherein said plurality of randomly-sized data packet pairs is sent more than once to said first node and said second nodes and the set of first delay times and the set of second delay times are based on the minimum delay for each packet size.

8. The method of claim 2 wherein the first and second data packets are ICMP-Echo request data packets.

9. The method of claim 2 wherein the first and second data packets are TCP data packets.

10. The method of claim 2 wherein the first and second data packets are UDP data packets.

11. A method for estimating at a host the available bandwidth as a function of time between a first node and a second node in a communication network comprising the steps of:

generating a known quantity of traffic at a location remote from said host;

injecting said known quantity of traffic into the network;

generating a plurality of randomly-sized data packet pairs each having a first data packet and a second data packet of equivalent size;

sending each of said first data packets from said host to said first node;

sending each of said second data packets from said host to said second node;

receiving a response from each of first and second nodes indicating receipt of said data packets;

generating a set of first delay times indicative of the time each of said first data packets required to reach said first node based on the received response;

generating a set of second delay times indicative of the time each of said second data packets required to reach said second node based on the received response;

estimating the traffic and router characteristic parameters, (γ

);

estimating the available bandwidth as a function of time based on said set of first delay times and said second delay times and the average available bandwidth for a short period of time.

12. The method of claim 11 wherein the steps of generating and injecting a known quantity of generated traffic into the network comprises sending K data sets from a traffic generator and the step of estimating the traffic and router characteristic parameters (γ

) according to nonlinear regression to solve the following relationship for said K sets of data

13. The method of claim 12 wherein α

_k(t), the estimated bandwidth for data sets K, is estimated in accordance with claim 6.

14. The method of claim 11 wherein the step of estimating the available bandwidth as a function of time based on said set of first delay times and said second delay times and the average available bandwidth for a short period of time is determined by the following relationship,

15. The method of claim 14 wherein α

(t) is estimated for a specific time (t) using a Bayesian point estimate according to the following relationship;

16. The method of claim 11 wherein the traffic and router characteristic parameters (γ

) are re-estimated only upon changes in the network configuration or traffic conditions.

18. The system of claim 17 further comprising a traffic generator for generating and injecting a known quantity of traffic into said network at a location remote from said network interface.

19. The system of claim 18 wherein said bandwidth estimator further comprises means for estimating the traffic and router characteristic parameters (γ

) and the available bandwidth as a function of time based on said set of first delay times and said second delay times and the average available bandwidth for a short period of time.

20. The system of claim 17 further comprising an input/output interface for communication with an end-user thereby enabling an end-user to estimate total and available bandwidth between two nodes in a communication network.

17. A system for the estimation of the bandwidth between two nodes in a communications network comprising:

a memory for storing an operating system and a bandwidth estimator program;

a processor in communication with said memory for executing instructions from said operating system and said bandwidth estimator program;

a network interface for sending and receiving data to and from said nodes in said communications network;

wherein said bandwidth estimator generates a plurality of randomly-sized data packet pairs each having a first data packet and a second data packet of equivalent size, sends said plurality of said first data packets to said first node through said network interface, sends said plurality of said second data packets to said second node through said network interface, receives response a response from each of first and second nodes through said network interface indicating receipt of said data packets, generates a set of first delay times indicative of the time each of said first data packets required to reach said first node, generates a set of second delay times indicative of the time each of said second data packets required to reach said second node and estimates the total bandwidth based on said set of first delay times and said second delay times.