METHOD FOR MULTICAST LOAD BALANCING IN WIRELESS LANS

• US 20080151807A1
• Filed: 02/22/2008
• Published: 06/26/2008
• Est. Priority Date: 11/01/2004
• Status: Active Grant

• Current Assignee: Douglas A. Smith, Nancy Cam Winget, Robert C. Meier, Stuart Norman
• Original Assignee: Douglas A. Smith, Nancy Cam Winget, Robert C. Meier, Stuart Norman
• Inventors: Meier, Robert C., Cam Winget, Nancy, Smith, Douglas A., Norman, Stuart
• Granted Patent: US 8,306,027 B2
• Time in Patent Office: Days
• US Class Current: 370/312
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 47/13 in a LAN segment, e.g. ring or bus
• CPC Class Codes: H04L 47/15 in relation to multipoint traffic arrangements for broadcast or multicast in data networks H04L12/18
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/782 Hierarchical allocation of resources, e.g. involving a hierarchy of local and centralised entities
• CPC Class Codes: H04L 47/801 Real time traffic
• CPC Class Codes: H04L 47/806 Broadcast or multicast traffic
• CPC Class Codes: H04L 47/824 Applicable to portable or mobile terminals
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A method for multicast load balancing in a wireless network having a plurality of access points. The method includes setting a maximum Internet protocol multicast bandwidth for the access points, receiving an admissions control request from a client at one of the access points, and determining whether the admissions control request from the client is for an admitted or unadmitted multicast stream at the access point. The access point is responsive to the admissions control request for the admitted multicast stream by servicing the admitted multicast stream and to the admissions control request for the unadmitted multicast stream by servicing the unadmitted multicast stream where the bandwidth required for the unadmitted multicast stream, plus that portion of the access point bandwidth currently used for all existing downlink multicast streams, does not exceed the maximum internet protocol multicast bandwidth for the access point.

Claims

1. A method, comprising:

receiving a request for a downlink multicast stream from a requester;

determining whether the requested downlink multicast stream is already being provided; and

rate limiting the requested downlink multicast stream to the requestor so that the bandwidth of the requested multicast stream and all previously admitted downlink multicast stream does not exceed a total bandwidth available for downlink multicast streams responsive to determining the requested downlink multicast stream is not already being provided and a sum of the bandwidth of the requested downlink multicast stream and previously admitted downlink streams exceed the total bandwidth available for downlink multicast streams;

wherein previously admitted downlink multicast streams are not rate limited.

2. The method in claim 1, wherein the downlink multicast stream is an internet protocol (IP) multicast stream, the method further comprises determining the bandwidth for IP multicast streams from an IP multicast router.

3. The method of claim 2, the determining whether the requested downlink multicast stream is already being provided further comprises determining one of a group consisting of a multicast destination IP address, and a unicast source IP address to identify the multicast stream.

4. The method in claim 2, the determining whether the requested downlink multicast stream is already being provided further comprises obtaining at least one of a group consisting of a multicast destination IP address, and a unicast source IP address for the requested downlink multicast stream from Internet Group Management Protocol Membership Report messages.

5. The method of claim 1, further comprising forwarding the requested downlink multicast stream to the requestor responsive to determining the multicast stream is already being provided.

6. The method of claim 1, further comprising forwarding the requested downlink multicast stream to the requestor without rate limiting responsive to determining the requested downlink multicast stream is not already being provided and a sum of the bandwidth of the requested downlink multicast stream and previously admitted downlink streams do not exceed the total bandwidth available for downlink multicast streams.

7. The method of claim 1, further comprising determining a bandwidth for the requested downlink multicast stream by measuring the bandwidth consumed by the requested downlink multicast stream over a period of time.

8. The method of claim 1, further comprising advertising that explicit admissions controls are in force for multicast streams.

9. The method of claim 1, wherein admissions control for multicast frames is based on Internet Group Management Protocol snooping.

10. The method of claim 9, further comprising:

determining whether the requested downlink multicast stream is being serviced by another access point within a Multicast Admissions Control Group;

forwarding the requested downlink multicast stream to the requestor responsive to determining the requested downlink multicast stream is not being serviced by another access point in the Multicast Admission Control Group; and

denying the request for the requested downlink multicast stream responsive to determining the requested downlink multicast stream is being serviced by another access point in the Multicast Admission Control Group.

11. An access point comprising:

a transceiver configured for wireless communication with a client; and

a controller coupled to the transceiver and operable for controlling the operation of the transceiver;

wherein the controller is configured for receiving a request for a downlink multicast stream from a requester;

wherein the controller is responsive to determine whether the requested downlink multicast stream is already being provided;

wherein the controller rate limits the requested downlink multicast stream to the requester so that the bandwidth of the requested multicast stream and all previously admitted downlink multicast stream does not exceed a total bandwidth available for downlink multicast streams responsive to determining the requested downlink multicast stream is not already being provided and a sum of the bandwidth of the requested downlink multicast stream and previously admitted downlink streams exceed the total bandwidth available for downlink multicast streams; and

wherein the controller does not rate limit previously admitted downlink multicast streams.

12. The apparatus of claim 11, wherein the downlink multicast stream is an internet protocol (IP) multicast stream;

and

wherein the controller is configured to communicate with an IP multicast router to determine the bandwidth for IP multicast streams from the IP multicast router.

13. The apparatus of claim 12, wherein the controller determines whether the requested downlink multicast stream is already being provided by determining one of a group consisting of a multicast destination IP address, and a unicast source IP address to identify the multicast stream.

14. The apparatus of claim 12, wherein the controller determines whether the requested downlink multicast stream is already being provided by obtaining at least one of a group consisting of a multicast destination IP address, and a unicast source IP address from Internet Group Management Protocol Membership Report messages.

15. The apparatus of claim 11, wherein the controller is configured to forward the requested downlink multicast stream to the requestor responsive to determining the multicast stream is already being provided.

16. The apparatus of claim 11, wherein the controller is further configured to forward the requested downlink multicast stream to the requestor without rate limiting responsive to determining the requested downlink multicast stream is not already being provided and a sum of the bandwidth of the requested downlink multicast stream and previously admitted downlink streams do not exceed the total bandwidth available for downlink multicast streams.

17. The apparatus of claim 11, wherein the controller is further configured to determine a bandwidth for the requested downlink multicast stream by measuring bandwidth consumed by the requested downlink multicast stream over a period of time.

18. The apparatus of claim 11, wherein the controller is further configured to advertise that explicit admissions controls are in force for multicast streams.

19. The apparatus of claim 11, wherein the controller is configured to provide admissions control for multicast frames based on Internet Group Management Protocol snooping.

20. An apparatus, comprising:

a controller communicatively coupled to a plurality of access points belonging to a Multicast Admission Control Group;

wherein the controller is configured to assign a first access point belonging to the Multicast Admission Control Group as a low bandwidth umbrella access point;

wherein the controller is configured to assign a second access point belonging to the Multicast Admission Control Group a high bandwidth channel and a coverage area that is smaller than a coverage area for the first access point;

wherein the controller configured to limit servicing of a multicast stream to either the first access point or the second access point, but not both; and

wherein the controller is configured to rate limit a high bandwidth stream being provided by the first access point while not rate limiting a low bandwidth stream being provided by the first access point.