Method to precisely and securely determine propagation delay and distance between sending and receiving node in packet network and packet network node system for executing the method

Abstract

A system and method for determining a propagation delay between nodes in a packet network are provided. The system and method include sending a ping packet from a source node to a destination node, determining an intermediate node delay of the ping packet at an intermediate node and recording the intermediate node delay in the ping packet and determining the propagation delay at the destination node by using the intermediate node delay.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects and advantages of embodiments of the present invention will become apparent and more readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a diagram illustrating a conventional method of determining a propagation delay and a distance between nodes in a packet network;

FIG. 2 is a diagram illustrating a method of determining a propagation delay and a distance between nodes in a packet network, according to exemplary embodiments of the present invention;

FIG. 3 is a flowchart illustrating a method of determining a propagation delay between nodes in a packet network according a first exemplary embodiment of the present invention;

FIG. 4 is a flowchart illustrating a method of determining an intermediate node delay according to the first exemplary embodiment of the present invention;

FIG. 5 illustrates an example of an internal configuration of a ping packet according to the first exemplary embodiment of the present invention;

FIG. 6 illustrates other example of an internal configuration of a ping packet according to the first exemplary embodiment of the present invention;

FIG. 7 is a diagram illustrating an example of a method of determining an intermediate node delay according to the first exemplary embodiment of the present invention;

FIG. 8 is a flowchart illustrating a method of determining a propagation delay in destination node according a first exemplary embodiment of the present invention;

FIG. 9 is a flowchart illustrating a method of determining a propagation delay between nodes in a packet network, according to a second embodiment of the present invention;

FIG. 10 is a flowchart illustrating a method of determining an intermediate node delay according to the second exemplary embodiment of the present invention;

FIG. 11 illustrates an example of internal configurations of a ping packet and a follow-up packet according to the second exemplary embodiment of the present invention;

FIG. 12 is a diagram illustrating an example of the method of determining the intermediate node delay according to the second exemplary embodiment of the present invention;

FIG. 13 is a flowchart illustrating a method of determining a propagation delay between nodes in a packet network, according to a third exemplary embodiment of the present invention;

FIG. 14 illustrates an example of an internal configuration of a ping packet according to the third exemplary embodiment of the present invention;

FIG. 15 is a diagram illustrating an example of a method of recording a link propagation delay in the ping packet at an intermediate node, according to the third exemplary embodiment of the present invention;

FIG. 16 illustrates examples of appending a digital signature to a ping packet or a follow-up packet, according to the first through third exemplary embodiments of the present invention; and

FIG. 17 is a block diagram illustrating an internal configuration of a propagation delay determining node in a packet network, according to a fourth exemplary embodiment of the present invention.

Claims

1. A method of measuring a propagation delay between nodes in a packet network, the method comprising: transmitting a ping packet from a first node to a second node through at least one of a plurality of third nodes;determining an intermediate node delay of the ping packet at one of the plurality of third nodes through which the ping is transmitted and recording the intermediate node delay in the ping packet; anddetermining a propagation delay by using the intermediate node delay.

2. The method of claim 1, wherein the determining of the propagation delay comprises determining of the propagation delay at the second node.

3. The method of claim 1, wherein the transmitting of the ping packet from a first node to a second node comprises: determining a departure time of the ping packet;recording the departure time in a departure time field of the ping packet; andtransmitting the ping packet to the second node.

4. The method of claim 1, wherein the determining of the intermediate node delay of the ping packet at one of the plurality of third nodes and recording the intermediate node delay in the ping packet comprises: receiving the ping packet and determining a third node arrival time;determining a third node departure time of the ping;determining the intermediate node delay by determining a difference between the third node departure time and the third node arrival time; andrecording the intermediate node delay in an intermediate node delay field included in the ping packet.

5. The method of claim 4, wherein the determining of the intermediate node delay of the ping packet at one of the plurality of third nodes and recording the intermediate node delay in the ping packet further comprises: transmitting the ping packet to another of the plurality of third nodes or the second node,wherein the intermediate node delay is accumulated in an accumulated delay field of the ping packet by the another third node or the second node.

6. The method of claim 1, wherein the determining of the intermediate node delay of the ping packet at one of the plurality of third nodes and recording the intermediate node delay in the ping packet comprises: receiving the ping packet at the one of the plurality of third nodes and determining a third node arrival time;determining a third node departure time of the ping;determining the intermediate node delay by using a difference between the third node departure time and the third node arrival time; andaccumulating the intermediate node delay in a departure time field included in the ping packet.

7. The method of claim 6, wherein the determining an intermediate node delay of the ping packet at one of the plurality of third nodes and recording the intermediate node delay in the ping packet further comprises: transmitting the ping packet to another of the plurality of third nodes or the second node,wherein, when the ping packet passes through two or more of the third nodes, the intermediate node delay is computed and accumulated in the departure time field of the ping packet by each of the two or more third nodes.

8. The method of claim 2, further comprising accumulating the intermediate node delay by a successive third node of the third node at which the intermediate node delay is determined or the second node, wherein the determining of the propagation delay at the second node by using the intermediate node delay comprises:determining an arrival time that the ping packet arrives at the second node;extracting the departure time and the intermediate node delay from the ping packet;computing the sum of the departure time and the intermediate node delay; anddetermining the propagation delay by subtracting the sum from the arrival time.

9. The method of claim 1, wherein the intermediate node delay is accumulated in the departure time field of the ping packet by the intermediate node determining the intermediate node delay, wherein the determining the propagation delay at the second node by using the intermediate node delay comprises:determining an arrival time that the ping packet arrives, at the second node;extracting the departure time accumulated the intermediate node delay from the departure time field; anddetermining the propagation delay by subtracting the departure time from the arrival time.

10. The method of claim 1, wherein: the packet network provides a timing signal for synchronization between nodes; andeach of the plurality of third nodes and the second node determines a time by using the timing signal at an instant of time that a first byte of the ping packet or a follow-up packet arrives.

11. The method of claim 1, further comprising: determining transmission speed of the ping packet; anddetermining a distance between the first node and at least one of the second node and plurality of third nodes, based on the transmission speed and the propagation delay.

12. The method of claim 1, wherein each of the first, second and plurality of third nodes through which the ping is transmitted in the packet network appends a digital signature to the ping packet or the follow-up packet, to be sent to an adjacent node to protect against unauthorized modification of the ping packet or the follow-up packet.

13. A computer-readable recording medium comprising instructions for executing a method of determining a propagation delay between nodes in a packet network is recorded, the instructions comprising: a first set of instructions for transmitting a ping packet from a first node to a second node through at least one of a plurality of third nodes;a second set of instructions for determining an intermediate node delay of the ping packet at one of the plurality of third nodes through which the ping is transmitted and recording the intermediate node delay in the ping packet; anda third set of instructions for determining a propagation delay by using the intermediate node delay.

14. A method of determining a propagation delay between nodes in a packet network, the method comprising: transmitting a ping packet from a first node to a second node and storing a departure time;recording the departure time in a follow-up packet and sending the follow-up packet to the second node;determining an intermediate node delay of the ping packet at a third node and recording the intermediate node delay in the follow-up packet; anddetermining a propagation delay at the second node, based on the ping packet and the follow-up packet.

15. The method of claim 14, wherein the determining an intermediate node delay of the ping packet at a third node and recording the intermediate node delay in the follow-up packet comprises: determining a third node arrival time that the ping packet arrives;determining a third node departure time that the ping packet departs;determining the intermediate node delay by using a difference between the third node departure time and the third node arrival time; andsending the follow-up packet recording the intermediate node delay in either a departure time field or an accumulated delay field of the follow-up packet.

16. The method of claim 14, further comprising accumulating the intermediate node delay in an accumulated delay field of the follow-up packet by the third node, wherein the determining of the propagation delay at the second node, based on the ping packet and the follow-up packet comprises:determining an arrival time of the ping packet;extracting the departure time and the intermediate node delay from the follow-up packet;computing the sum of the departure time and the intermediate node delay; anddetermining the propagation delay by subtracting the sum from the arrival time.

17. The method of claim 14, further comprising accumulating the intermediate node delay in a departure time field of the follow-up packet by the third node, wherein the determining of the propagation delay at the second node, based on the ping packet and the follow-up packet comprises:determining an arrival time of the ping packet;extracting the departure time from the follow-up packet; anddetermining the propagation delay by subtracting the departure time from the arrival time.

18. A method of determining a propagation delay between nodes in a packet network, the method comprising: transmitting a ping packet from a source node to a destination node;recording, in the ping packet at an intermediate node, a link propagation delay of a link in a path as the ping packet traverses the network; anddetermining the propagation delay at the destination node based on the link propagation delay.

19. The method of claim 18, wherein each node of the packet network computes and accumulates the link propagation delay for the link with an adjacent node.

20. The method of claim 18, wherein, when the ping packet passes through a plurality of the intermediate nodes, the link propagation delay is successively accumulated and recorded in the ping packet at the intermediate node.

21. The method of claim 18, wherein the determining the propagation delay at the destination node based on the link propagation delay comprises: receiving the ping packet;extracting the accumulated link propagation delays from the ping packet; anddetermining the link propagation delay as the propagation delay.

22. A propagation delay determining node system in a packet network, the system comprising: a first node unit for sending a ping packet for determining a propagation delay to a second node;a third node unit for determining an intermediate node delay of the ping packet and for recording the intermediate node delay in the ping packet when the ping packet whose destination is not the third node is received; anda second node unit for receiving the ping packet whose destination is the second node and for determining the propagation delay by using the intermediate node delay included in the ping packet.

23. The system of claim 22, wherein the first node unit comprises: a departure time determiner for determining a departure time that the ping packet departs;a departure time recorder for recording the departure time in a departure time field of the ping packet; anda ping packet sender for sending the ping packet to the second node.

24. The system of claim 22, wherein the third node unit comprises: a third node departure time determiner for receiving the ping packet and determining a third node arrival time;a third node departure time determiner for determining a third node departure time that the ping packet departs;a third node delay determiner for determining the intermediate node delay by using a difference between the third node departure time and the third node arrival time; anda third node delay recorder for recording the intermediate node delay in an intermediate node delay field included in the ping packet.

25. The system of claim 22, wherein the intermediate node unit comprises: a third node departure time determiner for receiving the ping packet and determining a third node arrival time;a third node departure time determiner for determining a third node departure time that the ping packet departs;a third node delay determiner for determining the intermediate node delay by using a difference between the third node departure time and the third node arrival time; anda third node delay accumulator for accumulating the intermediate node delay in an accumulated delay field included in the ping packet.

26. The system of claim 22, wherein the second node unit comprises: an arrival time determiner for determining an arrival time that the node receives the ping packet;a departure time extractor for extracting the departure time and an intermediate node delay from the ping packet;a sum computer for computing the sum of the departure time and an intermediate node delay; anda propagation delay determiner for determining the propagation delay by subtracting the sum from the arrival time.

27. The system of claim 22, wherein the second node unit comprises: an arrival time determiner for determining an arrival time that the node receives the ping packet;a departure time extractor for extracting the departure time from the ping packet; anda propagation delay determiner for determining the propagation delay by subtracting the departure time from the arrival time field.