Minimizing Packet Loss During Fast Roaming

• US 20090052412A1
• Filed: 08/23/2007
• Published: 02/26/2009
• Est. Priority Date: 08/23/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Dharanipragada, Kalyan, Kumar, Rajneesh, O'Hara, Robert B. JR.
• Granted Patent: US 8,085,710 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off

Abstract

A packet loss reduction system. In particular implementations, a method includes responsive to indications of roaming intent of a wireless client relative to currently associated wireless access point, determining if a traffic stream associated with the wireless client is to be proactively buffered by one or more potential wireless access points; conditionally transmitting a command to the one or more potential wireless access points to cause the potential, wireless access points to set up resources to proactively buffer packets of the traffic stream; duplicating received packets of the traffic stream destined for the wireless client; and transmitting the duplicate packets to the potential wireless access points for storage in a proactive stream buffer.

Claims

1. Logic encoded in one or more tangible media for execution and when executed operable to:

responsive to indications of roaming intent of a wireless client relative to currently associated wireless access point, determine if a traffic stream associated with the wireless client is to be proactively buffered by one or more potential wireless access points;

conditionally transmit a command to the one or more potential wireless access points to cause the potential wireless access points to set up resources to proactively buffer packets of the traffic stream;

duplicate received packets of the traffic stream destined for the wireless client; and

transmit the duplicate packets to the potential wireless access points for storage in a proactive stream buffer.

2. The logic of claim 1 wherein the logic is further operable to transmit the received packets to the currently associated wireless access point.

3. The logic of claim 1 wherein the logic Is further operable to cause the potential wireless access points to transmit the duplicated packets to the wireless client only after associating with the wireless client.

4. The logic of claim 1 wherein the traffic stream associated with the wireless client, is to be proactively buffered if the traffic stream is of a predefined class.

5. The logic of claim 1 wherein the traffic stream associated with the wireless client is to be proactively buffered if the traffic stream is a voice traffic stream or a video traffic stream.

6. The logic of claim 1 wherein the logic is further operable to detect an indication of a roaming intent based on detection of a pre-reservation process initiated by the wireless client.

7. The logic of claim 1 wherein the command causes the potential wireless access points to expire duplicate packets after a predefined time period.

8. The logic of claim 1 wherein the command causes the potential wireless access points to expire the command after a predefined time period.

9. The logic of claim 1 wherein the logic is further operable to:

identify one or more parent mesh access points in a mesh network based on potential mesh access points to which the wireless client can roam;

cause the parent mesh access points to duplicate the received packets destined for the wireless client; and

cause the parent mesh access points to transmit the duplicate packets to the potential mesh access points for storage in a buffer.

10. A method comprising:

responsive to indications of roaming intent of a wireless client relative to currently associated wireless access point, determining if a traffic stream associated with the wireless client is to be proactively buffered by one or more potential wireless access points;

conditionally transmitting a command to the one or more potential wireless access points to cause the potential wireless access points to set up resources to proactively buffer packets of the traffic stream;

duplicating received packets of the traffic stream destined for the wireless client; and

transmitting the duplicate packets to the potential wireless access points for storage in a proactive stream buffer.

11. The method of claim 10 further comprising transmitting the received packets to the currently associated wireless access point.

12. The method of claim 10 further comprising causing the potential wireless access points to transmit the duplicated packets to the wireless client only after associating with the wireless client.

13. The method of claim 10 wherein the traffic stream associated with the wireless client is to be proactively buffered if the traffic stream is of a predefined class.

14. The method of claim 10 wherein the traffic stream associated with the wireless client is to be proactively buffered if the traffic stream is a voice traffic stream or a video traffic stream.

15. The method of claim 10 further comprising detecting an indication of a roaming intent based on detection of a pre-reservation process initiated by the wireless client.

16. The method of claim 10 wherein the command causes the potential wireless access points to expire duplicate packets after a predefined time period.

17. The method of claim 10 wherein the command causes the potential wireless access points to expire the command after a predefined time period.

18. The method of claim 10 further comprising:

identifying one or more parent, mesh access points in a mesh network based on potential mesh access points to which the wireless client can roam;

causing the parent mesh access points to duplicate the received packets destined for the wireless client; and

cause the parent mesh access points to transmit, the duplicate packets to the potential mesh access points for storage in a buffer.

19. Logic encoded in one or more tangible media, for execution and when executed operable to:

responsive to a command from a controller, reserve resources to buffer duplicate packets of a wireless client associated with a currently associated wireless access point;

receive duplicate packets for a wireless client;

store the duplicate packets in a buffer; and

transmit the duplicated packets to the wireless client, after associating with the wireless client.

20. The logic of claim 19 wherein the logic is further operable to expire the duplicate packets after a predefined time period.

21. The logic of claim 19 wherein the logic is further operable to expire the command after a predefined time period.

22. The logic of claim 19 wherein, upon association with the wireless client, the logic is further operable to merge any duplicate packets stored in the buffer with one or more transmission queues for delivery to the wireless client.

23. A method comprising:

responsive to a command from a controller, reserving resources to buffer duplicate packets of a wireless client associated with a currently associated wireless access point;

receiving duplicate packets for a wireless client;

storing the duplicate packets in a buffer; and

transmitting the duplicated packets to the wireless client after associating with the wireless client.

24. The method of claim 23 further comprising expiring the duplicate packets after a predefined time period.

25. The method of claim 23 further comprising expiring the command after a predefined time period.

26. The method of claim 23 further comprising, upon association with the wireless client, merging any duplicate packets stored in the buffer with one or more transmission queues for delivery to the wireless client.