Method to accurately and securely determine propagation delay and distance between sending and receiving node in packet network using cut-through approach and packet network node for executing the method

• US 20070189184A1
• Filed: 11/16/2006
• Published: 08/16/2007
• Est. Priority Date: 02/11/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Garner, Geoffrey M., Feng, Fei Fei, Ryu, Hyun Surk, Den Hollander, Cornelis Johannis, Jung, Kyu Hong
• Granted Patent: US 8,018,973 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route

Abstract

A method and system for measuring a distance between nodes in a packet network are provided. The system and method include measuring and storing a departure time of a ping packet sent from a source node to a destination node, sending a response packet with respect to the ping packet from the destination node to the source node, cutting through the ping packet or response packet to a successive node or the destination node without an intermediate node delay, computing a round-trip time by measuring an arrival time of the response packet at the source node and measuring the distance between the nodes, based on the round-trip time and speed of the ping packet.

Claims

1. A method of measuring a distance 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 a departure time of the ping packet;

transmitting a response packet with respect to the ping packet from the second node to the first node through the at least one of the plurality of the third nodes;

prioritizing a transmission of at least one of the ping packet and response packet from the at least one of the plurality of third nodes;

determining a round-trip time by determining an arrival time of the response packet; and

determining a distance based on the round-trip time and a speed of the ping packet.

2. The method of claim 1, wherein the prioritizing of the transmission comprises transmitting the at least one of the ping packet and the response packet without a delay at the at least one of the plurality of third nodes.

3. The method of claim 2, wherein the prioritizing of the transmission of the at least one of the ping packet and response packet without delay comprises:

receiving the at least one of the ping packet and the response packet by at least one of the third nodes;

giving priority to the received at least one of the ping packet and response packet;

storing other packets being sent or waiting for transmission;

suspending transmission of the other packets;

transmitting the received at least one of the ping packet and response packet to at least one of another third node and the second node; and

resuming transmission of the other packets after the transmission of at least one of the ping packet and response packet is completed.

4. The method of claim 2, wherein the transmitting a response packet with respect to the ping packet from the second node to the first node comprises:

exchanging an address of the first node included in the ping packet with an address of the second node included in the ping packet;

changing a packet type identifier included in the ping packet from a ping type to a response type; and

sending the ping packet to the first node, as the response packet.

5. The method of claim 1, wherein each of the first node, the second node and the plurality of third nodes comprise a dedicated unit for processing a input packet input and each of the first node, the second node and the at least one of the plurality of third nodes of the packet network processes the ping packet, the response packet, or the intermediate node delay via the dedicated unit.

6. A method of processing a packet in a dedicated unit included in each node in a packet network, the method comprising:

receiving a packet at a node in a packet network;

determining a packet kind of the packet received at the node; and

processing the packet at the node, based on the packet kind.

7. The method of claim 6, wherein the processing of the packet at the node, based on the packet kind comprises removing a delay of the packet at the node and sending the packet to a successive node when the packet is not destined for the node.

8. The method of claim 7, wherein the removing of the delay of the packet at the node and sending the packet to a successive node comprises:

assigning pre-emptive priority to the packet when receiving the packet;

storing other packets being transmitted or waiting for transmission;

suspending transmission of the other packets;

transmitting the packet to the successive node or a destination node; and

resuming transmission of the other packets after the transmission of the packet is completed.

9. The method of claim 6, wherein the processing of the packet at the node, based on the packet kind comprises;

changing a field of the packet;

sending the packet to a source node from which the packet originated.

10. The method of claim 9, wherein the sending of the packet to the source node comprises:

changing a destination address of the packet into an address of the source node;

changing a packet type identifier included in the packet from a ping type into a a response type; and

sending the ping packet to the source node, as the response packet.

11. The method of claim 10, further comprising authenticating the packet by the node wherein the packet responds to the authentication of the node by using a security key shared with the packet network.

12. The method of claim 6, wherein the processing the packet at the node, based on the packet kind comprises determining a distance by computing a round-trip time, when the packet kind is a response packet destined for the node.

13. The method of claim 12, wherein the determining of the distance comprises:

determining an arrival time of the packet at the node;

determining a departure time of the packet from the node;

computing the round-trip time by using a difference between the arrival time and the departure time; and

determining the distance based on the round-trip time and speed of the packet.

14. A computer-readable recording medium including a set of instructions for executing a method of measuring a distance 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 a departure time of the ping packet;

a third set of instructions for transmitting a response packet with respect to the ping packet from the second node to the first node through the at least one of the plurality of the third nodes;

a fourth set of instructions for prioritizing a transmission of at least one of the ping packet and response packet from the at least one of the plurality of third nodes;

a fifth set of instructions for determining a round-trip time by determining an arrival time of the response packet; and

a sixth set of instructions for determining a distance based on the round-trip time and a speed of the ping packet.

15. A node system for measuring a distance between nodes in a packet network, the system comprising:

a source node unit for transmitting a ping packet to a destination node, for determining and storing a departure time of the ping packet, and for measuring a distance between nodes in a packet network;

a destination node unit for receiving the ping packet and sending a response packet corresponding to the ping packet when the received the ping packet is destined for the destination node;

an intermediate node unit for prioritizing transmission of at least one of the ping packet and the response packet to a successive node without an intermediate node delay;

a computer for computing a round-trip time by determining an arrival time when a response packet destined for the node is received; and

a distance measurer for determining a distance between the source node and the destination node, based on the round-trip time.

16. The node of claim 15, wherein the intermediate node unit comprises:

a pre-emptive priority giver for giving pre-emptive priority to at least one of the ping packet and response packet when receiving the ping packet or response packet respectively;

a transmission suspender for storing other packets being transmitted or waiting for transmission and suspending transmission;

a packet sender for transmitting the ping packet to the successive node or the destination node; and

a resume sending unit for resuming transmission of the other packets after the transmission of the at least one of the ping packet and the response packet is completed.

17. The node of claim 15, wherein the destination node unit comprises:

an address exchanger for exchanging a source address and a destination address included in the ping packet;

a packet type changer for changing a packet type included in the ping packet into a packet type of the response packet; and

a packet sender for sending the ping packet to the source node, as the response packet.