Network communication system with information rerouting capabilities

• US 6,049,533 A
• Filed: 02/25/1998
• Issued: 04/11/2000
• Est. Priority Date: 10/04/1995
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Aironet Wireless Communications, Inc. (Cisco Systems, Inc.)
• Inventors: Norman, Stuart G., Sojka, Marvin
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): Sam, Phirin
• Application Number:
  US09/030,717
• Time in Patent Office: 776 Days
• Field of Search: 370/328-331, 370/338, 370/349, 370/389, 370/395, 370/400-406, 370/339, 370/342, 370/344, 370/347, 370/350, 370/353, 370/356, 370/386, 370/392, 370/396, 455/435, 455/436, 455/428, 455/445
• US Class Current: 370/328
• CPC Class Codes: H04L 45/34 Source routing
• CPC Class Codes: H04W 36/00 Hand-off or reselection arrangements
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A network communication system in which access points providing wireless access to the system reroute misrouted information packets in the event the location of a mobile unit has changed. Regardless of whether a host computer or other network device is capable of updating in its position table the changing locations of the mobile units, information packets directed to the mobile units from the host computer or other network device are still properly delivered.

Claims

1. A network communication system, comprising:

a communication network including a plurality of nodes; and

a plurality of access points each coupled to said communication network at a respective one of said nodes, said access points serving as communication links between said communication network and one or more mobile communication units, each of said access points including;

wireless communication means for communicating information between said respective node and any of said one or more mobile communication units which are registered to said access point;

means for receiving an information packet from said communications network, said information packet being addressed to a particular one of said one or more mobile communication units;

means for transmitting said information packet to said particular mobile communication unit, via said wireless communication means, in the event said particular mobile communication unit is currently registered to said access point;

means for rerouting said information packet to said particular mobile communication unit via said communication network in the event said particular mobile communication unit is not currently registered to said access point;

means for storing information relating to the current location of each of said one or more mobile communication units; and

means for communicating to each of the other access points which of the one or more mobile communication units are currently registered thereto, wherein said means for communicating automatically communicates said registration information periodically.

2. The system of claim 1, wherein said communication network comprises a token ring configuration.

3. The system of claim 1, wherein each of said access points comprises means for maintaining a table of which of said one or more mobile communication units are currently registered to said access point.

4. The system of claim 1, wherein said information relating to the current location of each of said one or more mobile communication units is derived based upon source routing information developed within the communication network.

5. The system of claim 1, wherein at least two of said access points are connected to said communication network in a token ring configuration, and said at least two access points include means for electing a ring master responsible for rerouting said information packet.

6. The system of claim 1, wherein said means for rerouting comprises means for providing source routing information.

7. The system of claim 1, wherein said wireless communication means comprises an RF transceiver.

8. The system of claim 1, wherein said wireless communication means comprises an optical transceiver.

12. The method of claim 2, wherein said information relating to the current location of each of said one or more mobile communication units is derived based upon source routing information developed within the communication network.

9. In a network communication system comprising a communication network having a plurality of nodes, and a plurality of access points each coupled to said communication network at a respective one of said nodes, said access points serving as respective wireless communication links between said communication network and one or more mobile communication units registered thereto, a method of communicating an information packet including the steps of:

directing an information packet over said communication network to a particular one of said access points to which a particular one of said one or more mobile communication units is considered to be registered;

using said particular access point to transmit said information packet to said particular mobile communication unit via wireless communication in the event the particular mobile communication unit is currently registered therewith;

using one of said plurality of access points to reroute said information packet to said particular mobile communication unit via said communication network in the event said particular mobile communication unit is not currently registered to said particular access point, wherein said rerouting step includes the step of storing information relating to the current location of each of said one or more mobile communication units in each access point, each of said access points communicating to each of the other access points which of the one or more mobile communication units are currently registered thereto, wherein said access points each communicate said registration information periodically.

10. The method of claim 9, wherein said communication network comprises a token ring configuration.

11. The method of claim 9, wherein said rerouting step includes the step of maintaining for each access point a log of which of said one or more mobile communication units are currently registered to said access point.

13. The method of claim 9, wherein at least two of said access points are connected to said communication network in a token ring configuration, one of said at least two access points being said particular access point towards which said information packet is directed, and further including the step of electing a ring master among said at least two access points such that said ring master is responsible for rerouting said information packet.

14. The method of claim 9, wherein said rerouting step comprises the step of inserting source routing information to reroute said information packet included in said information packet.

15. An access point for use in a network communication system comprising a communication network having a plurality of nodes, said access point together with a plurality of similar access points each which are coupled to said communication network at a respective one of said nodes, with each of said access points serving as a respective wireless communication link between said communication network and one or more mobile communication units registered thereto, said access point comprising:

wireless communication means for communicating information between said respective node and any of said one or more mobile communication units which are registered to said access point;

means for receiving an information packet from said communications network, said information packet being addressed to a particular one of said one or more mobile communication units;

means for transmitting said information packet to said particular mobile communication unit, via said wireless communication means, in the event said particular mobile communication unit is currently registered to said access point;

means for rerouting said information packet to said particular mobile communication unit via said communication network in the event said particular mobile communication unit is not currently registered to said access point;

means for maintaining a log of which of said one or more mobile communication units are currently registered to said access point;

means for storing information relating to the current location of each of said one or more mobile communication units; and

means for communicating to each of the other similar access points which of the one or more mobile communication units are currently registered thereto, wherein said means for communicating automatically communicates said registration information periodically.

16. The access point of claim 15, wherein said information relating to the current location of each of said one or more mobile communication units is derived based upon source routing information developed within the communication network.

17. The access point of claim 15, wherein at least two of said access points are connected to said communication network in a token ring configuration, and said at least two access points include means for electing a ring master responsible for rerouting said information packet.

18. The access point of claim 15, wherein said means for rerouting comprises means for providing source routing information.

19. A network communication system comprising:

(a) a communication network including a plurality of nodes;

(b) a plurality of mobile data collection units; and

(c) a plurality of access points each coupled to said communication network at a respective one of said nodes, operating to convey routed data packets between the communication network and a destination mobile data collection unit, each access point comprising;

(1) a transmission system for wirelessly communicating one or more data packets to the destination mobile data collection unit in the event that the destination mobile data collection unit is within a wireless communication area;

(2) a reroute system for communicating said data packets to the destination mobile data collection unit through the communication network in the event that the mobile unit is not within said wireless communication area, wherein the reroute system includes a current position table identifying route information used to reroute the data packets to the destination mobile data collection unit; and

(3) means for communicating to each of the other access points which of the one or more mobile communication units are currently registered thereto, wherein said means for communicating automatically communicates said registration information periodically.

20. The network of claim 19, wherein each of said data packets includes route information in a routing field which identifies rings and bridges in a token ring network.

21. The network of claim 19, wherein in each of said data packets rerouted via the reroute system includes source routing information.