Method of measuring distance between equipments on lan and distance measuring apparatus

• US 5,550,807 A
• Filed: 09/27/1994
• Issued: 08/27/1996
• Est. Priority Date: 03/04/1994
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kuroshita, Kazumasa
• Primary Examiner(s): Kizou, Hassan
• Application Number:
  US08/313,438
• Time in Patent Office: 700 Days
• Field of Search: 370/13, 370/131, 370/17, 370/85.1, 370/85.13, 370/94.1, 340/825.06, 340/825.15, 340/825.17, 340/825.49, 340/825.54, 340/825.55, 364/561, 364/569, 379/25, 342/125
• 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

Abstract

In measuring the distance and the positional relationship between the equipments on a LAN, a first equipment transmits a request packet to each of the other equipments at a predetermined interval of time. When each of the other equipments receives the request packet, it supplies the response packet to the first equipment. The first equipment calculates the distance between the first equipment and each of the other equipments on the basis of the time at which the request packet has been transmitted and the time at which the response packet has been received, and stores the calculated distance in the network structure information table NWT. Since the packet transmission speed changes in accordance with the traffic volume, the calculated distance is compared with the distance stored in the network structure information table NWT, and only when the calculated distance is shorter, it is stored in the network structure information table NWT.

Claims

1. A method of measuring the distance between the equipments on a LAN comprising the steps of:

transmitting a request packet periodically from a first equipment to each of the other equipments;

.

transmitting a response packet from each equipment which has received said request packet to said first equipment;

calculating by said first equipment a distance between said first equipment and each of the other equipments on the basis of the time at which said request packet has been transmitted and the time at which said response packet has been received; and

storing the calculated distance in a memory, wherein said step of storing said calculated distance includes the steps of;

comparing said calculated distance with a distance previously stored in said memory;

updating said distance stored in said memory when said calculated distance is shorter; and

discarding said calculated distance and holding said distance stored in said memory when said calculated distance is longer.

2. A method of measuring the distance between the equipments on a LAN according to claim 1, further comprising the step of drawing the network structure of said LAN on a display screen on the basis of the distance between the equipments.

3. A method of measuring the distance between the equipments on a LAN according to claim 1, wherein when said LAN is constituted by a bus network, said method further comprises the steps of:

calculating by a second equipment on the LAN the distance between said second equipment and each of the other equipments; and

obtaining positional relationship and the distance between the equipments on the basis of the distance calculated by said first equipment and the distance calculated by said second equipment.

4. A method of measuring the distance between the equipments on a LAN according to claim 3;

further comprising the step of drawing the network structure of said LAN on a display screen on the basis of the positional relationship and the distance between the equipments.

5. A method of measuring the distance between the equipments on a plurality of LANs connected with each other through an intermediate apparatus for LAN--LAN connection, comprising the steps of:

transmitting a request packet periodically from each intermediate apparatus for LAN--LAN connection to each equipment on the LAN under its command and each adjacent intermediate apparatus;

transmitting a response packet from each equipment and each adjacent intermediate apparatus which has received said request packet to each intermediate apparatus which has transmitted said request packet;

calculating by each intermediate apparatus the distance between said intermediate apparatus and each equipment on the LAN under its command and the distance between said intermediate apparatus and each adjacent intermediate apparatus on the basis of the time at which said request packet has been transmitted and the time at which said response packet has been received;

storing the calculated distances in a memory; and

calculating by a management terminal on a LAN the distance between the equipments on each LAN on the basis of the distance information collected by each intermediate apparatus.

6. A method of measuring the distance between the equipments on a plurality of LANs according to claim 5, wherein said step of storing the calculated distances in a memory includes the steps of:

comparing said calculated distance with a distance previously stored in said memory;

updating said distance stored in said memory when said calculated distance is shorter; and

discarding said calculated distance and holding said distance stored in said memory when said calculated distance is longer.

7. A method of measuring the distance between the equipments on a plurality of LANs according to claim 5, further comprising the step of drawing the network structure of said LANs on a display screen on the basis of the distance between the equipments.

8. A method of measuring the distance between the equipments on a plurality of LANs according to claim 5, wherein when said LANs are constituted by a bus network, said method further comprises the steps of:

calculating by one equipment on each LAN the distance between said one equipment and each of the other equipments; and

obtaining positional relationship and the distance between the equipments on the basis of the distances calculated by each intermediate apparatus for LAN--LAN connection and the distance calculated by said one equipment.

9. A method of measuring the distance between the equipments on a plurality of LANs according to claim 5, further comprising the step of drawing the network structure of said LANs on a display screen on the basis of the positional relationship and the distance between the equipments.

10. A distance measuring apparatus in one of equipments for measuring the distance between the equipments on a LAN, said apparatus comprising:

a transmitter/receiver for transmitting a request packet periodically to the other equipments and receiving a response packet to said request packet from the other equipments;

a storage portion for storing the time at which said request packet has been transmitted and the time at which said response packet has been received in correspondence with a name of an address equipment

a distance calculating portion for calculating the distance to each of the other equipments on the basis of the time at which said request packet has been transmitted and the time at which said response packet has been received; and

a storage unit for storing the calculated distance in correspondence with the name of the address equipment;

wherein said distance calculating portion compares said calculated distance with the distance stored in said storage unit, and updates said distance stored in said storage unit only when said calculated distance is shorter.