Method for multicast load balancing in wireless LANs

• US 20060094440A1
• Filed: 11/01/2004
• Published: 05/04/2006
• Est. Priority Date: 11/01/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Meier, Robert C., Cam Winget, Nancy, Smith, Douglas A., Norman, Stuart
• Granted Patent: US 7,362,776 B2
• Time in Patent Office: Days
• US Class Current: 455/453
• 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. An access point, comprising:

a transceiver for receiving an admissions control request from a client; and

a controller coupled to the transceiver for controlling the operation of the transceiver and setting a maximum multicast bandwidth for the access point;

the controller configured for determining whether the admissions control request from the client is for one of an admitted multicast stream and an unadmitted multicast stream, each stream having a bandwidth;

wherein the controller is responsive to the admissions control request for the admitted multicast stream by servicing the admitted multicast stream; and

wherein the controller is responsive 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 is less than a maximum multicast bandwidth for the access point.

2. The access point of claim 1, wherein the access point is a member of Multicast Admissions Control Group.

3. The access point of claim 1, wherein the access point advertises that explicit admissions controls are in force for multicast streams so that the client is ensured that the requested multicast stream will not be rate limited.

4. The access point of claim 1, the controller further configured for determining whether a requested multicast stream is being serviced by another access point;

wherein the access point is responsive to the determination of whether the requested multicast stream is being serviced by another access point by servicing the requested multicast stream where the requested multicast stream is not being serviced by another access point; and

wherein the access point is responsive to the determination of whether the requested multicast stream is being serviced by another access point by denying access to the client where the requested multicast stream is being serviced by another access point.

5. The access point of claim 4, wherein the access point is further responsive to the determination of whether the requested multicast stream is being serviced by another access point by directing the client to the access point servicing the requested multicast stream where the requested multicast stream is being serviced by another access point.

6. The access point of claim 5, wherein multicast admissions control is coordinated by a central access point controller that is in communication with the access point.

7. The access point of claim 6, wherein the access point forwards the admissions control request from the client to the central access point controller.

8. The access point of claim 6, wherein the central access point controller applies load balancing to admitted multicast streams to select the access point for servicing the client.

9. The method in claim 8, wherein the central access point controller comprises an IP multicast router that measures the bandwidth consumed by an IP multicast stream, which it is forwarding, over a period of time;

where the IP multicast router forwards bandwidth information for IP multicast streams to the controller; and

where the controller uses the bandwidth information to determine if a multicast stream can be admitted at an access point.

10. The access point of claim 1, wherein the client is able to determine whether the access point will accept the admissions control request for the multicast stream by including the admissions control request in a Probe Request.

11. The access point of claim 10, wherein the access point indicates multicast bandwidth availability in at least one of a Probe Response and a Beacon frame.

12. The access point of claim 1 wherein a client associated to a second access point sends an admissions control request message to the access point and receives an admission control response message from the access point to determine if the access point will accept a downlink IP multicast stream.

13. An access point, comprising:

a transceiver for receiving a request from a client for a multicast stream, wherein at least one of the access point and the client does not support admissions control; and

a controller coupled to the transceiver configured for determining whether the request is for one of an admitted multicast stream and an unadmitted multicast stream;

wherein the access point is responsive to the request by forwarding an admitted multicast stream to the client; and

wherein the access point is responsive to the request for an unadmitted multicast stream by rate limiting the unadmitted multicast stream to the client.

14. The access point of claim 13, the controller further configured for categorizing the multicast stream, identified by one of a destination multicast address, and a destination multicast address and a unicast source address, as one of admitted and unadmitted.

15. The access point of claim 13, wherein admissions control is based on Internet Group Management Protocol snooping.

16. A method for multicast load balancing in a wireless network having a plurality of access points, comprising:

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 one of an admitted multicast stream and an unadmitted multicast stream at the access point, each stream having a bandwidth;

wherein the one of the access points is responsive to the admissions control request for the admitted multicast stream by servicing the admitted multicast stream; and

wherein the one of the access points is responsive 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.

17. The method of claim 16, further comprising forming a Multicast Admissions Control Group from the plurality of access points.

18. The method of claim 16, wherein at least one of the access points advertises that explicit admissions controls are in force for multicast streams.

19. The method of claim 16, wherein the multicast admissions control is used to distribute multicast streams across access points in the same coverage area.

20. The method of claim 16, further comprising:

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

wherein the one of the access points is responsive to the determination of whether the requested multicast stream is being serviced by another access point by servicing the requested multicast stream where the requested multicast stream is not being serviced by another access point; and

wherein the one of the access points is responsive to the determination of whether the requested multicast stream is being serviced by another access point by denying access to the client where the requested multicast stream is being serviced by another access point.

21. The method of claim 20, wherein the one of the access points is further responsive to the determination of whether the requested multicast stream is being serviced by another access point by directing the client to the access point servicing the requested multicast stream where the requested multicast stream is being serviced by another access point.

22. The method of claim 21, wherein admissions control are coordinated by a central access point controller that is in communication with the plurality of access points.

23. The method of claim 22, wherein the plurality of access points forward multicast admissions control requests from clients to the central access point controller.

24. The method of claim 22, wherein the central access point controller applies load balancing to admitted multicast streams to select a parent access point for the client.

25. The method of claim 16, wherein the client is able to determine which access point will accept the admissions control request for a downlink multicast stream by including the admissions control request in a Probe Request.

26. The method of claim 25, wherein the one of the access points indicates multicast bandwidth availability in at least one of a Probe Response and a Beacon frame.

27. A method for multicast load balancing in a wireless network having a plurality of access points, comprising:

receiving a request from a client for a multicast stream at one of the access points, wherein at least one of the one of the access points and the client does not support admissions control; and

determining whether the admissions control request is for one of an admitted multicast stream and an unadmitted multicast stream;

wherein the one of the access points is responsive to the request by forwarding an admitted multicast stream to the client; and

wherein the one of the access points is responsive to the request for the unadmitted multicast stream by rate limiting the unadmitted multicast stream to the client.

28. The method of claim 27, further comprising categorizing the multicast stream, identified by one of a destination multicast address and a destination multicast address and unicast source address, as one of admitted and unadmitted.

29. The method of claim 27, wherein the admissions control is based on Internet Group Management Protocol snooping.

34. The computer-readable medium of instructions for multicast load balancing of claim 29, further comprising:

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

wherein the one of the access points is responsive to the determination of whether the requested multicast stream is being serviced by another access point by servicing the requested multicast stream where the requested multicast stream is not being serviced by another access point; and

wherein the one of the access points is responsive to the determination of whether the requested multicast stream is being serviced by another access point by denying access to the client where the requested multicast stream is being serviced by another access point.

35. The computer-readable medium of instructions for multicast load balancing of claim 34, wherein the one of the access points is further responsive to the determination of whether the requested multicast stream is being serviced by another access point by directing the client to the access point servicing the requested multicast stream where the requested multicast stream is being serviced by another access point.

36. The computer-readable medium of instructions for multicast load balancing of claim 35, wherein admissions control are coordinated by a central access point controller means that is in communication with the plurality of access points.

37. The computer-readable medium of instructions for multicast load balancing of claim 36, wherein the plurality of access points forward multicast admissions control requests from clients to the central access point controller.

38. The computer-readable medium of instructions for multicast load balancing of claim 37, wherein the central access point controller applies load balancing to admitted multicast streams to select a parent access point for the client.

30. A computer-readable medium of instructions for multicast load balancing in a wireless network having a plurality of access points, comprising:

means for setting a maximum Internet protocol multicast bandwidth for the access points;

means for receiving an admissions control request from a client at one of the access points; and

means for determining whether the admissions control request from the client is for one of an admitted multicast stream and an unadmitted multicast stream at the access point, each stream having a bandwidth;

wherein the one of the access points is responsive to the admissions control request for the admitted multicast stream by servicing the admitted multicast stream; and

wherein the one of the access points is responsive 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.

31. The computer-readable medium of instructions for multicast load balancing of claim 30, further comprising means for forming a Multicast Admissions Control Group from the plurality of access points.

32. The computer-readable medium of instructions for multicast load balancing of claim 31, wherein the one of the access points advertises that explicit admissions controls are in force for multicast streams so that the client is ensured that the requested multicast stream will not be rate limited.

33. The computer-readable medium of instructions for multicast load balancing of claim 30, wherein the multicast admissions control is used to distribute multicast streams across access points in the same coverage area.

39. The computer-readable medium of instructions for multicast load balancing of claim 30, wherein the client is able to determine which access point will accept the admissions control request for a downlink multicast stream by including the admissions control request in a Probe Request.

40. The computer-readable medium of instructions for multicast load balancing of claim 39, wherein the access point indicates multicast bandwidth availability in at least one of a Probe Response and a Beacon frame.

41. A computer-readable medium of instructions for multicast load balancing in a wireless network having a plurality of access points, comprising:

means for receiving a request from a client for a multicast stream at one of the access points, wherein at least one of the one of the access points and the client does not support admissions control; and

means for determining whether the admissions control request is for one of an admitted multicast stream and an unadmitted multicast stream;

wherein the one of the access points is responsive to the admissions control request by forwarding an admitted multicast stream to the client; and

wherein the one of the access point is responsive to the admissions control request for the unadmitted multicast stream by rate limiting the unadmitted multicast stream to the client.

42. The computer-readable medium of instructions for multicast load balancing of claim 41, further comprising means for categorizing the multicast stream, identified by a destination multicast address, as one of admitted and unadmitted.

43. The computer-readable medium of instructions of claim 41, further comprising means for the admissions control to be based on Internet Group Management Protocol snooping.

44. A method for organizing a wireless LAN, comprising

assigning an umbrella access points an umbrella channel that covers the entire wireless LAN

assigning at least one other access point a relatively high-bandwidth channel that covers a select Hot Spot area;

rate limiting a high-bandwidth downlink multicast streams on the umbrella access point; and

migrating a client using an explicit admissions control signal to receive a high-bandwidth multicast streams, to a one of the at least one other access points.

45. The method in claim 44 further comprising

organizing a group of at least two access points, which are covering the same Hot Spot area into a multicast admissions control group, wherein a high-bandwidth multicast stream is only forwarded on a single access point in the multicast admissions control group.

46. A method for managing multicast streams, comprising

limiting the total bandwidth consumed by downlink multicast streams at an access point;

classifying a multicast stream as one of admitted and unadmitted;

determining the bandwidth for the multicast stream by measuring the bandwidth consumed by the multicast stream over a period of time; and

admitting a new downlink multicast stream to an access point if the bandwidth required by the new multicast stream plus the bandwidth for existing multicast streams does not exceed the limit for all downlink multicast streams at the access point;

wherein an unadmitted multicast stream is rate-limited.

47. The method in claim 46 further comprising

determining the bandwidth for IP multicast streams by an IP multicast router forwarding IP multicast bandwidth information to a controller by the IP multicast router;

and

determining by the controller if a new multicast stream is admitted or unadmitted.

48. The method in claim 47 further comprising

forwarding at least one of a multicast destination IP address, and a multicast destination IP address and a unicast source IP address, which identify a multicast stream, to the controller;

determining the admissions control status by the controller; and

communicating by the controller the admissions control status to the access point.

49. The method in claim 48 further comprising

obtaining at least one of a the multicast destination IP address, and the multicast destination IP address and the unicast source IP address from Internet Group Management Protocol Membership Report messages.