System for discovering and maintaining geographic location information in a computer network to enable emergency services

• US 7,194,354 B1
• Filed: 10/30/2003
• Issued: 03/20/2007
• Est. Priority Date: 06/19/2001
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Oran, David R., Gai, Silvano
• Primary Examiner(s): Black; Thomas
• Assistant Examiner(s): Behncke; Christine M.
• Application Number:
  US10/697,896
• Time in Patent Office: 1,237 Days
• Field of Search: 710/9, 710/8, 379/45, 379/142.1, 379/201.06, 379/37, 370/351
• US Class Current: 701/207
• CPC Class Codes: G01S 19/17 Emergency applications
• CPC Class Codes: G01S 2205/006 for emergency situations
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac

Abstract

A system automatically discovers and maintains geographic location information for entities and devices making up a computer network. The system preferably includes a computing unit and a geographic location generator, such as a Global Positioning System (GPS) receiver. The computing unit includes a location discovery entity and a message generator. The GPS receiver, which is mounted to and in communication with the computing unit, may be augmented with an inertial navigation unit to facilitate the generation of location information inside of buildings where GPS signals can be difficult to receive. The computing unit further includes a network communications facility so that it can communicate with one or more network devices, such as a network switch. The switch includes a location recording/reporting entity and a location database. Physical coordinates of network entities or devices are obtained by the GPS receiver and/or inertial navigation unit and transmitted to the network switch, and the recording/reporting entity stores the physical coordinates at the location database.

Claims

1. A method for discovering and maintaining geographic location information for network devices, the method comprising the steps of:

interconnecting a first network device to a particular port of an intermediate network device, the first network device including a location generator configured to determine physical coordinates corresponding to the location of the first network device;

transmitting, by the first network device, a message including the physical coordinates of the first network device to the intermediate network device, the intermediate network device receiving the messages on a particular port;

storing the physical coordinates at a memory location of the intermediate network device, the memory location associated with the particular port;

subsequent to the step of transmitting, disconnecting the first network device from the particular port and interconnecting a second network device to the particular port, the second network device located at substantially the same location as previously occupied by the first network device; and

determining the physical location of the second network device by accessing the memory location associated with the particular port.

2. The method of claim 1 wherein the second network device lacks internal capability of determining physical coordinates.

3. The method of claim 1 further comprising the step of:

transmitting the physical coordinates to the second network device in response to a request by the second network device.

4. The method of claim 1 further comprising the step of:

appending the physical coordinates to an emergency call to a third network device, the emergency call originated by the second network device.

5. The method of claim 1 further comprising the step of:

passing the physical coordinates from the intermediate network device to a second intermediate network device, to be stored at the second intermediate network device.

6. The method of claim 5 wherein the step of passing further comprise the steps of:

generating an Internet Control Message Protocol (ICMP) message;

loading the physical coordinates into the ICMP message; and

sending the ICMP message to the second intermediate network device.

7. The method of claim 1 wherein the first network device is a portable computing unit and the second network device is a Voice over Internet Protocol (VoIP) phone.

8. The method of claim 7 wherein intermediate network device is a network switch.

9. An intermediate network device configured to maintain geographic location information for network devices, comprising:

a geographical location recording/reporting entity configured to communicate with a first network device coupled to a particular port of the intermediate network device, and configured to receive from the first network device physical coordinates corresponding to the location of the first network device;

a non-volatile memory configured to store the physical coordinates in one or more memory locations associated with the particular port, the physical coordinates thereby associated with the particular port; and

the geographical location recording/reporting entity is further configured to, in response to receiving a request from a second network device coupled to the particular port, assume the second network device is located at substantially the same location as the first network device, and transmit the physical coordinates to the second network device.

10. The intermediate network device of claim 9 wherein the non-volatile memory includes a geo-location table indexed by port number, and wherein the memory locations associated with the particular port are part of the geo-location table.

11. The intermediate network device of claim 9 wherein the geographical location recording/reporting entity is further configured to append the physical coordinates to an emergency call to a third network device, the emergency call originated by the second network device.

12. A method for discovering and using the geographic location information with a Voice over Internet Protocol (VoIP) telephone, the method comprising the steps of:

interconnecting the VoIP telephone to a particular port of a network switch, the particular port associated with a memory entry in a memory of the network switch, the memory entry storing predetermined physical coordinates for use with any network device interconnected to the particular port;

receiving the physical coordinates at the VoIP telephone from the intermediate network device; and

appending, by the VoIP telephone, the physical coordinates to at least one call message transmitted by the VoIP telephone.

13. The method of claim 12 wherein the at least one call is part of an emergency call to a Public Safety Answering Point (PSAP).

14. The method of claim 12 further comprising the step of:

requesting, by the VoIP telephone, the physical coordinates from the switch.

15. The method of claim 14 wherein the step of requesting further comprises the step of:

transmitting one or more Internet Control Message Protocol (ICMP) messages to the network switch.

16. A computer readable medium containing executable program instructions for discovering and using geographic location information with a Voice over Internet Protocol (VoIP) telephone, the executable program instructions comprising program instructions adapted for:

transmitting a message from the VoIP Telephone to a particular port of a network switch that is interconnected to the telephone, the message requesting physical coordinates for the VoIP telephone;

in response to the message, receiving the physical coordinates from the switch at the VoIP Telephone;

appending, by the VoIP telephone, the physical coordinates to an emergency call transmitted by the VoIP telephone.

17. The computer readable medium of claim 16 wherein the emergency call is to a Public Safety Answering Point (PSAP).