Roaming of clients between gateways of clusters of a wireless mesh network

• US 20070192506A1
• Filed: 02/15/2006
• Published: 08/16/2007
• Est. Priority Date: 02/15/2006
• Status: Active Grant

• Current Assignee: Hitachi Energy Limited (Hitachi, Ltd.)
• Original Assignee: Tropos Networks Incorporated (ABB Limited)
• Inventors: Vogety, Ramanagopal, Gupta, Mukesh, Chari, Amalavoyal, Chavali, Srikanth
• Granted Patent: US 8,700,800 B2
• Time in Patent Office: Days
• US Class Current: 709/238
• CPC Class Codes: H04L 2212/00 Encapsulation of packets
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

A method and apparatus of allowing client roaming between gateways of a wireless mesh network is disclosed. The gateways are connected through a layer 3 network to an aggregation router. The method includes a first gateway sending a first route update to the aggregation router when a client joins a first cluster of the first gateway, the first gateway aging the route, and a second gateway sending a second route update to the aggregation router when the client roams to a second cluster of the second gateway.

Claims

1. A method of a wireless mesh network gateway aging a client route, the wireless mesh network gateway being connected to an aggregation router, comprising:

the mesh network gateway assigning a cost function corresponding with a client route an initial value when the mesh network gateway installs the client route;

the mesh network gateway aging the client route by incrementing the cost function over time;

the mesh network gateway updating the aggregation router with the cost function every time the cost function changes value.

2. The method of claim 1, wherein the client route is aged by incrementing the cost function once every set period of time.

3. The method of claim 1, wherein the cost function is capped at a maximum value.

4. The method of claim 1, wherein the initial value of the cost function is zero

5. The method of claim 1, wherein the mesh network updating the aggregation router comprises a BGP route update.

6. The method of claim 5, wherein an age of the client route is communicated to the aggregation router via a Multi Exit Discriminator of the BGP route update that carries the age.

7. A method of allowing client roaming between gateways of a wireless mesh network, the gateways being connected to an aggregation router across a layer three network through tunnels, the method comprising:

a first gateway sending a first route update of a first route to the aggregation router when a client joins a first cluster of the first gateway;

the first gateway aging the first route;

a second gateway sending a second route update to the aggregation router when the client roams to a second cluster of the second gateway.

8. The method of claim 7, wherein the tunnels comprise GRE tunnels.

9. The method of claim 7, wherein the tunnels comprise IP in IP tunnels.

10. The method of claim 7, wherein the tunnels comprise L2TP tunnels.

11. The method of claim 7, wherein aging the first route comprises incrementing a cost function over time.

12. The method of claim 7, wherein the first route update and the second route update comprise BGP route updates.

13. The method of claim 12, wherein the route updates enable the aggregation router to update its route to the client based upon a cost function corresponding with each of the BGP route updates.

14. The method of claim 12, wherein first route update and the second route update enable the aggregation router to use the route to the client that corresponds with the BGP route having a lowest cost function.

15. The method of claim 13, wherein a cost function corresponding with the first BGP route is assigned an initial value when the first gateway installs the client route, and the client route is aged by incrementing the cost function.

16. The method of claim 7, wherein the second gateway ages the second route update over time.

17. The method of claim 16, wherein a cost function corresponding with the second route update is assigned an initial value when the second gateway installs the client route, and aged by incrementing the cost function.

18. A computer program operable on a processing unit of a mesh network gateway, the gateway connected to an aggregation router through a layer three network, the computer program executing a method comprising:

assigning a cost function corresponding with a BGP client route an initial value when the mesh network gateway installs a client route;

aging the BGP client route by incrementing the cost function over time;

updating the aggregation router with the cost function every time the cost function changes value.

19. The computer program of claim 18, wherein the BGP client route is aged by incrementing the cost function once every set period of time.

20. The computer program of claim 18, wherein the cost function is capped at a maximum value.