Network communication system with information rerouting capabilities

• US 5,737,328 A
• Filed: 10/04/1995
• Issued: 04/07/1998
• 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): Olms, Douglas W.
• Assistant Examiner(s): NGO, RICKY QUOC
• Application Number:
  US08/539,130
• Time in Patent Office: 916 Days
• Field of Search: 370/328, 370/329, 370/330, 370/331, 370/338, 370/349, 370/400, 370/401, 370/402, 370/403, 370/404, 370/405, 370/406, 455/33.1, 455/33.2, 379/59, 379/60
• US Class Current: 370/331
• 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 communication network, said information packet being addressed to a particular one of said one or more mobile communication units;

means for determining whether said access point is a master among a plurality of said access points according to a predefined criteria independent of whether the particular mobile communication unit has been registered to said access point;

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; and

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 and said access point is determined to be the master.

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 each of said access points comprises means for storing information relating to the current location of each of said one or more mobile communication units.

5. The system of claim 4, 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.

6. The system of claim 4, wherein each of said access points comprises means for communicating to each of the other access points which of the one or more mobile communication units are currently registered thereto.

7. The system of claim 6, wherein said means for communicating automatically communicates said registration information periodically.

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

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

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

20. The access point of claim 1, wherein said access point comprises means for maintaining a log of which of said one or more mobile communication units are currently registered to said access point.

21. The access point of claim 20, wherein said access point comprises means for storing information relating to the current location of each of said one or more mobile communication units.

22. The access point of claim 21, 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.

23. The access point of claim 21, wherein said access point comprises means for communicating to each of the other similar access points which of the one or more mobile communication units are currently registered thereto.

24. The access point of claim 23, wherein said means for communicating automatically communicates said registration information periodically.

11. 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;

electing one of said plurality of access points to be a master among said plurality of access points according to a predefined criteria independent of whether the particular mobile communication unit has been registered to said access point; and

using said access point elected master 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.

12. The method of claim 11, wherein said communication network comprises a token ring configuration.

13. The method of claim 11, 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.

14. The method of claim 12, 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.

15. The method of claim 14, 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.

16. The method of claim 14, further including the step of 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.

17. The method of claim 16, wherein said access points each communicate said registration information periodically.

18. The method of claim 11, wherein said rerouting step comprises the step of inserting source routing information to reroute said information packet included in said information packet.

30. The method of communicating of claim 11, wherein election of a master is reassessed periodically over time.

19. 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 communication network, said information packet being addressed to a particular one of said one or more mobile communication units;

means for determining whether said access point is a master among a plurality of said access points according to a predefined criteria independent of whether the particular mobile communication unit has been registered to said access point;

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; and

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 and said access point is determined to be the master.

25. The access point of claim 19, wherein said means for rerouting comprises means for providing source routing information.

26. 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 a transmission system for wirelessly communicating said 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, and a reroute system for communicating said data packet to the destination mobile data collection unit through the communication network in the event that the mobile data collection unit is not within a wireless communication network and the access point has been elected a master among said plurality of access points according to a predefined criteria independent of whether the destination mobile data collection unit has been registered to said access point.

27. The network of claim 26, wherein each of said data packets includes route information in a routing field which identifies rings and bridges in a token ring network.

28. The network of claim 27, wherein the reroute system includes a current position table identifying route information used to reroute the packet to the destination mobile unit.

29. The network of claim 26, wherein in each of said data packets rerouted via the reroute system includes source routing information.