CAPWAP/LWAPP multicast flood control for roaming clients

• US 7,873,020 B2
• Filed: 10/01/2007
• Issued: 01/18/2011
• Est. Priority Date: 10/01/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Woodhams, Jacob E., Ghosh, Sujit, Stiff, David M., Broch, Joshua G., Hunt, David
• Primary Examiner(s): Sheikh; Ayaz R
• Assistant Examiner(s): Wong; Blanche
• Application Number:
  US11/865,512
• Publication Number:
  US 20090086689A1
• Time in Patent Office: 1,205 Days
• Field of Search: None
• US Class Current: 370/338
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 4/08 User group management
• CPC Class Codes: H04W 8/18 Processing of user or subscriber data, e.g. subscribed services, user preferences or user profiles; Transfer of user or subscriber data

Abstract

A method, an apparatus, a system, and logic encoded in one or more computer-readable tangible medium to carry out a method. The method includes maintaining the state of clients of an access point controlled by a controller in the controller of the access point, including multicast group information, and updating the access point with multicast group identification for the clients, such that the controller in combination with the access point can forward packets, and such that multicast group information for a roaming client of the access point is maintained.

Claims

1. A method comprising:

at a first controller controlling and having one or more secure links to one or more respective access points of a wireless network;

receiving a plurality of data packets including at least one predetermined identifier operative to identify one or more multicast groups, the first controller controlling access point functionality of the first controller'"'"'s respective access points;

maintaining a controller-maintained client state data structure including an entry for any client of any access point controlled by the first controller, the entry for a client including multicast group information for the client;

selecting the data packets of the received data packets that match information in the client state data structure; and

forwarding the controller-selected data packets to one or more of the access points controlled by the first controller,

such that a first access point controlled by the first controller and maintaining a multicast group data structure of one or more multicast groups that any client or clients associated with the first access point are members of, as a result of receiving the controller-selected packets forwarded by the first controller, is operative to;

look up the first access point'"'"'s multicast group data structure,

select the data packets of the controller-selected received packets that match information in the multicast group data structure, and

wirelessly transmits the access-point-selected packets,

wherein the controlling of the access point functionality of an access point by the access point'"'"'s controller uses commands conforming to a protocol and sent to the respective access point via the secure link to the access point.

2. A method as recited in claim 1, wherein the wireless network is a network conforming to the IEEE 802.11 standard, and the protocol is Control And Provisioning of Wireless Access Points (CAPWAP) or Light Weight Access Point Protocol (LWAPP).

3. A method as recited in claim 1, further comprising:

detecting that a first client of the first access point has roamed;

in the case that the roam is to a second access point controlled by the first controller, instructing the second access point to change its multicast group data structure;

in the case the roam is to a second access point controlled by a second controller, the first controller receiving a mobility message from the second controller regarding the first client and sending information on the first client to the second controller;

ascertaining if a change to the first controller'"'"'s client state data structure is needed and, if the change is needed, changing the contents of the first controller'"'"'s client state data structure; and

instructing the first access point to change the first access point'"'"'s multicast group data structure.

4. A method as recited in claim 3, wherein the first controller detecting is as a result of receiving information from the first access point.

5. A method as recited in claim 3, wherein the first controller detecting is as a result of the first controller receiving the mobility message.

6. A method as recited in claim 3, wherein in the case the roam is to a second access point controlled by a second controller, and in the case the second controller is ascertained to be in the same network as the first controller, the changing of the contents of the client state data structure includes deleting the entry for the first client.

7. A method as recited in claim 3,

wherein in the case the roam is to a second access point controlled by a second controller, in the case the second controller is ascertained not to be in the same network as the first controller, and in the case the roam is ascertained to be the first roam of the first client,

the changing of the contents of the client state data structure includes adding an indication to the entry for the first client that the controller is the anchor controller for the first client, and

the method further comprises forming a tunnel between the first and second controller,

such that the second controller can receive multicast group information on the first client that is roaming from the first controller, ascertain if a change to the second controller'"'"'s client state data structure is needed, and if so, change the contents of its client state data structure to account for the roaming first client; and send group membership information to upstream to a network of the second controller.

8. A method as recited in claim 7, wherein receiving of multicast group information on the roaming first client by the second controller from the first controller is as a result of the second controller instructing the second access point to issue a query to the roaming first client to provide the roaming first client'"'"'s multicast group information;

as a result of the roaming first client responding to the query, and as a result of the second controller receiving from the second access point group membership information.

9. A method as recited in claim 8, wherein the query and the responding to the query conform to an Internet Group Management Protocol (IGPM) query and a response to an IGMP query, respectively.

10. A system comprising:

a first controller in a wireless network operative to control one or more wireless access points, the first controller including a memory subsystem operative to store a client state data structure including an entry for client or clients of the one or more wireless access point controlled by the first controller, an entry for a client including multicast group information for the client; and

a first wireless access point having a secure link with the first controller, and whose access point functionality is controlled by the first controller using commands conforming to a protocol and sent via the secure link, the first wireless access point including a memory subsystem operative to store a multicast group data structure of one or more multicast groups that any client or clients associated with the first wireless access point are members of,

such that the first controller receiving data packets including at least one predetermined identifier operative to identify one or more multicast groups, is operative to select the data packets of the received data packets that match information in the client state data structure for clients of the first access point and forward the controller-selected data packets to the access point, and

such that the first wireless access point as a result of receiving the controller-selected packets forwarded by the first controller, is operative to;

look up the first access point'"'"'s its multicast group data structure,

select the data packets of the controller-selected packets that match information in the multicast group data structure, and

wirelessly transmits the access-point-selected packets.

11. A system as recited in claim 10, wherein the wireless network is a network conforming to the IEEE 802.11 standard, and the protocol is Control And Provisioning of Wireless Access Points (CAPWAP) or Light Weight Access Point Protocol (LWAPP).

12. A system as recited in claim 10,

wherein, as a result of a first client of the first access point roaming, the first controller is operative to:

detect that a first client of the first access point has roamed,

in the case that the roam is to a second access point controlled by the first controller, instruct the second access point to change the second access point'"'"'s multicast group data structure;

in the case the roam is to a second access point controlled by a second controller,

receive a mobility message from the second controller regarding the first client, and

send information on the first client to the second controller;

ascertain if a change to its the first controller'"'"'s client state data structure is needed and, if the change is needed, change contents of the first controller'"'"'s client state data structure; and

instruct the first access point to change the first access point'"'"'s multicast group data structure, and

wherein, the first access point is operative to;

as a result receiving instruction from the first controller to change the first access point'"'"'s multicast group data structure, change the first access point'"'"'s multicast group data structure.

13. A system as recited in claim 12,

wherein in the case the roam is to a second access point controlled by a second controller, and in the case the second controller is ascertained to be in the same network as the first controller, the changing of contents of the client state data structure of the first controller includes deleting the entry for the first client.

14. A system as recited in claim 12,

wherein in the case the roam is to a second access point controlled by a second controller, in the case the second controller is ascertained not to be in the same network as the first controller, and in the case the roam is ascertained to be the first roam of the first client, the changing the of contents of the client state data structure by the first controller includes adding an indication to the entry for the first client that the controller is the anchor controller for the first client, the first controller further operative to form a tunnel between the first and second controller,

such that the second controller can receive multicast group information on the roaming first client, ascertain if a change to the second controller'"'"'s client state data structure is needed and, if so, change contents of its client state data structure to account for the roaming first client;

and send group membership information upstream to the second controller'"'"'s network.

15. A controller comprising:

one or more network interfaces operative to couple a controller to a network and further operative to couple the controller to a first wireless access point of a wireless network, the coupling between the controller and the first wireless access point including a secure link over which commands are sendable that conform to a protocol and that are to control access point functionality of the first wireless access point, the first wireless access point including a memory subsystem operative to store a multicast group data structure of one or more multicast groups that any client or clients associated with the first wireless access point are members of,

a memory subsystem operative to store a client state data structure including an entry for client or clients of the access point or points controlled by the controller;

an entry for a client including multicast group information for the client; and

logic configured such that as a result of the controller receiving a plurality of data packets including at least one predetermined identifier operative to identify one or more multicast groups, the controller is operative to select the data packets of the received data packets that match information in the client state data structure for clients of the first wireless access point and forward the controller-selected data packets to the access point,

such that the first wireless access point as a result of receiving the controller-selected packets forwarded by the controller, is operative to;

look up the first wireless access point'"'"'s multicast group data structure,

select the data packets of the received controller-selected packets that match information in the multicast group data structure, and

wirelessly transmits the access-point-selected packets.

16. A controller as recited in claim 15, wherein the wireless network is a network conforming to the IEEE 802.11 standard, and the protocol is Control And Provisioning of Wireless Access Points (CAPWAP) or Light Weight Access Point Protocol (LWAPP).

17. A controller as recited in claim 15, wherein the logic includes logic encoded in one or more tangible media that is executable by one or more processors of a processing system included in the controller.

18. A controller as recited in claim 15, wherein the logic is further configured such that as a result of a first client of the first access point roaming, the controller is operative to:

detect that a first client of the first access point has roamed,

in the case that the roam is to a second access point controlled by the controller, instruct the second access point to change the second access point'"'"'s multicast group data structure;

in the case the roam is to a second access point controlled by a different controller,

receive a mobility message from the different controller regarding the first client, and

send information on the first client to the different controller;

ascertain if a change to the controller'"'"'s client state data structure is needed and, if the change is needed, change contents of the controller'"'"'s client state data structure; and

instruct the first access point to change the second wireless access point'"'"'s multicast group data structure, and

wherein, the first access point is operative to;

as a result receiving instruction from the controller to change the first access point'"'"'s multicast group data structure, change the first access point'"'"'s multicast group data structure.

19. A controller as recited in claim 18,

wherein in the case the roam is to a second access point controlled by a different controller, and in the case the different controller is ascertained to be in the same network as the controller, the changing of contents of the client state data structure of the controller includes deleting the entry for the first client.

20. A controller as recited in claim 18,

wherein in the case the roam is to a second access point controlled by a different controller, in the case the different controller is ascertained not to be in the same network as the controller, and in the case the roam is ascertained to be the first roam of the first client, the changing the of contents of the client state data structure by the controller includes adding an indication to the entry for the first client that the controller is the anchor controller for the first client, the controller further operative to form a tunnel between the first and different controller,

such that the different controller can receive multicast group information on the roaming first client, ascertain if a change to the different controller'"'"'s client state data structure is needed, if so, change contents of the different controller'"'"'s client state data structure to account for the roaming first client;

and send group membership information to upstream to the different controller'"'"'s network.