Patent Publication Number: US-10327186-B2

Title: Aggregated beacons for per station control of multiple stations across multiple access points in a wireless communication network

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority as a continuation of U.S. patent application Ser. No. 14/504,403, filed Oct. 1, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 14/337,184, filed Jul. 21, 2014, which is a continuation of U.S. patent application Ser. No. 12/913,584 filed Oct. 27, 2010 (now issued U.S. Pat. No. 8,787,309), which is a continuation of U.S. patent application Ser. No. 11/715,287 filed Mar. 7, 2007 (now issued U.S. Pat. No. 7,826,426), the contents of each being hereby incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to wireless computer networking, and more specifically, to providing per station control of multiple stations across multiple access points. 
     BACKGROUND 
     Wireless computing technologies provide untethered access to the Internet and other networks. One of the most critical technologies for wireless networking (or Wi-Fi) is the IEEE 802.11 family of protocols promulgated by the Institute of Electrical and Electronics Engineers. Currently, the protocols are widely adopted in stations such as laptop computers, tablet computers, smart phones, and network appliances. 
     Stations complying with standards such as IEEE 802.11 have control over how a connection to wireless network is made. Namely, a station selects an access point among a number of access points that have sent out beacons advertising a presence. The beacon includes a BSSID (Basic Service Set Identifier) as an identifier of the access point. In turn, the station sends data packets which include the BSSID of the intended access point. Unintended access points receiving a transmission merely ignore the data packets. 
     One technique to address this issue is to download customized software to a station. But reconfiguration of stations running on a station is not always desirable. For instance, guests connecting to a public hot spot for only one time would be burdened with the process of downloading and installing a client during a short connection. Furthermore, many computer users are weary about malicious applications downloaded from the Internet. 
     Another technique to address this issue, known as virtual port, assigns a BSSID to each station in order to set uplink parameters. Unfortunately, the overhead of virtual port is prohibitive for scaling because regular beacons are sent out for each BSSID to maintain synchronization with an access point. In larger deployments, the occurrence of still beacons increase as the requirement for individual beacons required over each period cannot be met. Consequentially, degradation of station connectivity can occur, for instance, when 20 or more wireless stations are connected to the access point. 
     What is needed is a robust technique to provide a more scalable solution for per station control of multiple stations across multiple access points in a wireless communication network. 
     SUMMARY 
     These shortcomings are addressed by the present disclosure of methods, computer program products, and systems for providing per station control of multiple stations across multiple access points in a wireless communication network. Aggregated beacons with multiple BSSIDs (Basic Service Set Identifiers) can maintain connections for multiple stations without requiring separate beacons, for example, according to protocols such as IEEE 802.11k, IEEE 802.11v and IEEE 802.11r (collectively referred to herein as “IEEE 802.11 kvr”). 
     In an embodiment, a look-up table that assigns a station connected to the access point and at least one communication parameter to each of a plurality of persistent, uniquely-assigned BSSIDs is stored. An access point responds to messages addressed to one of the plurality of persistent, uniquely-assigned BSSIDs and ignores messages addressed to other BSSIDs of other access points. Uniqueness of BSSIDs allows the controller to individualize communication parameters for specific stations. Persistence of the BSSIDs allows the controller to maintain individual control over each station moving across different access point of the plurality of access points. 
     In one embodiment, the plurality of BSSIDs corresponding to each connected station is aggregated into the frame when generated. For example, the frame can be compliant with a Multiple BSSID element of the IEEE 802.11 standards. The frame is then transmitted to the plurality of stations connected to an access point in order to connect, or maintain connections with an access point. Alternatively, BSSIDs can be sent in responses to probes received from a station. Responsive to a station of the plurality of stations being handed-off to a different access point, a uniquely-assigned BSSID corresponding to the station is deleted from the look-up table. 
     Advantageously, virtual port control is scalable for large deployments, and without the overhead of sending individual beacons for each station of a deployment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following drawings, like reference numbers are used to refer to like elements. Although the following figures depict various examples of the invention, the invention is not limited to the examples depicted in the figures. 
         FIG. 1  is a high-level block diagram illustrating a system to provide per station control of multiple stations across multiple access points, according to one embodiment. 
         FIGS. 2A-C  are high-level block diagrams illustrating a spatial layout of the system of  FIG. 1 , according to one embodiment. 
         FIG. 3  is a more detailed block diagram illustrating a controller of the system of  FIG. 1 , according to one embodiment. 
         FIG. 4  is a more detailed block diagram illustrating an access point of the system of  FIG. 1 , according to one embodiment. 
         FIG. 5  is a sequence diagram illustrating interactions between components of the system of  FIG. 1 , according to one embodiment. 
         FIG. 6  is a flow diagram illustrating a method for providing per station control of multiple stations across multiple access points from a controller, according to one embodiment. 
         FIG. 7  is a flow diagram illustrating a method for providing per station control of multiple stations across multiple access points from an access point, according to one embodiment. 
         FIG. 8  is a schematic diagram illustrating an exemplary IEEE 802.11 network packet with multiple BSSIDs (Basic Service Set Identifiers), according to one embodiment. 
         FIG. 9  is a block diagram illustrating an exemplary computing device, according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention provides methods, computer program products, and systems for providing per station control of multiple stations across multiple access points in a wireless communication network. For example, uniquely-assigned and persistent BSSIDs (Basic Service Set Identifiers) can be aggregated into a Multiple BSSID element according to IEEE 802.11 specifications. Additionally, one of ordinary skill in the art will recognize that many other scenarios are possible, as discussed in more detail below. 
     Systems to Provide Per Station Control of Multiple Stations Across Multiple Access Points ( FIGS. 1-5 ) 
       FIG. 1  is a high-level block diagram illustrating a system  100  to provide per station control of multiple stations across multiple access points, according to one embodiment. The system  100  comprises stations  110 A-N, access points  120 A-N, and a controller  130 . The components can be coupled to a network  199 , such as the Internet, a local network or a cellular network, through any suitable wired (e.g., Ethernet) or wireless (e.g., Wi-Fi or 4G) medium, or combination. In a preferred embodiment, the stations  110 A-N are coupled to the access points  120 A-N through a wireless communication channel  115 A-N while the access points  120 A-N can be coupled to the controller  130  through a wired network  125  (e.g., Ethernet network). Other embodiments of communication channels are possible, including a cloud-based controller, and hybrid networks. Additional network components can also be part of the system  100 , such as firewalls, virus scanners, routers, switches, application servers, databases, and the like. In general, the stations  110 A-N use communication channels  115 A-N for uplink (and downlink) access to local and/or external networks. 
     The controller  130  can be implemented in any of the computing devices discussed herein (e.g., see  FIG. 9 ). For example, the controller  130  can be an MC1500 or MC6000 device by Meru Networks of Sunnyvale, Calif. In operation, the controller  130  communicates with each of the access point  120  to direct parameters for each of the stations  110 A-N. Moreover, the controller  130  determines, in one embodiment, which access point of many should communicate with a particular one of the stations  110 A-N, among other things. The controller  130  can also solely or jointly determine parameters for each station. In one example, the controller  130  varies the parameters based on a top-level network view of traffic and congestion (i.e., provide less access during heavy traffic and more during light traffic). The controller  130  can also track the stations  110 A-N through connections to different access points and enforce the same parameters after hand-offs. Additional embodiments of the controller  130  are discussed with respect to  FIG. 3 . 
     To implement virtual port functionality for per station control of the stations  110 A-C, in an embodiment, the controller  130  can maintain a global look-up table or database with a global view (e.g., network-wide view) of connected stations and other devices. The global look-up table stores a uniquely-assigned BSSID for each station configured for virtual port. All or some stations can be so configured. Additionally, the global look-up table stores parameters, for each BSSID, shared or not. Alternatively, a list of BSSIDs can be stored and stations are associated and de-associated therewith. In one embodiment, a BSSID is generated to be unique by incorporating a device-unique identification, such as a MAC address of a station. The controller  130  sends a BSSID to a selected access point to initiate the association. In one example, a BSSID is a 48-bit field of the same format as an IEEE 802 MAC address that uniquely identifies a BSS (Blind Service Set). 
     The controller  130  provides seamless mobility functionality for hand-offs between access points while maintaining the same BSSID, in one embodiment. In further detail, a station can be handed-off from one access point to another access point by the controller  130  de-associating the former access point and associating the new access points. The hand-off can be substantially transparent to the affected station because although a different access point is responding to communications, the BSSID persists. 
     Accordingly, the full-featured virtual port functionality with seamless mobility is enabled with BSSIDs that are both uniquely-assigned across all devices on the system  100  and persistent through hand-offs between the access points  120 A-N. 
     Algorithms to initially set parameters, to adjust the parameters, and to determine which access point is assigned to a particular station are all implementation-specific. In one example, the controller  130  discriminates parameters for particular users or groups of users (e.g., CEO, network administrator, authenticated user, guest, suspicious station, etc.), for particular types of computers (e.g., critical data server, rarely-accessed archival data storage, etc.), for particular types of traffic (streaming high-definition (HD) video, low bandwidth video, secure data, voice, best effort, background, etc.), and the like. Initial default parameters can be uniform and adjusted once the access point  120  gathers more information about a particular station such as traffic patterns. For instance, over use by a particular station can be controlled. More detailed embodiments of the controller  130  are set forth below with regards to  FIG. 3 . 
     The access points  120 A-N include one or more individual access points implemented in any of the computing devices discussed herein (e.g., see  FIG. 9 ). For example, the access points  120 A-C can be an AP 110 or AP 433 (modified as discussed herein) by Meru Networks of Sunnyvale, Calif. A network administrator can strategically place the access points  120 A-N for optimal coverage area over a locale. The access points  120 A-N can, in turn, be connected to a wired hub, switch or router connected to the network  199 . In another embodiment, the functionality is incorporated into a switch or router. 
     In operation, the access points  120 A-N can maintain a local look-up table with an local view (e.g., access point-wide) of connected stations and other devices. The local look-up table stores BSSIDs assigned by the controller  130 . All or some of the BSSIDs can be uniquely-assigned and/or persistent BSSIDs. For virtual port and seamless mobility functionality, the access points  120 A-N can receive real-time associations and de-associations for the stations  110 A-N. Periodic beacons are transmitted by the access points  120 A-N to advertise availability and maintain connections. As such, the access points  120 A-N can respond to messages addressed to BSSIDs for the local look-up table and ignore messages addressed to other BSSIDs. 
     In one embodiment, the access points  120 A-N aggregate multiple BSSIDs into a single beacon. For example, protocols such as IEEE 802.11 kvr inherently support a multiple BSSID element in beacon and probe response. In some cases, aggregated BSSIDs belong to the same class, channel and antennae connector. Optionally, BSSID aggregation can be toggled on and off automatically based on a number of connected stations. Example frame structures are shown in  FIG. 7 . More detailed embodiments of the access points  120 A-N are discussed below with respect to  FIG. 4 . 
     The stations  110 A-N can be, for example, a personal computer, a laptop computer, a tablet computer, a smart phone, a mobile computing device, a server, a cloud-based device, a virtual device, an Internet appliance, or the like (e.g., see  FIG. 9 ). No special client is needed for this particular technique, although other aspects of the network may require downloads to the stations  110 A-N. The stations  110 A-N connect to the access points  120 A-N for access to, for example, a LAN or external networks. In one embodiment, a child plays video games on a wireless game console as a station in communication with streaming applications from a cloud-based application server. In a different embodiment, an employee authenticates from a laptop as a station over a secure channel of an enterprise network to modify remotely stored secure files. In another embodiment, a guest at a coffee shop uses a smart phone as a station to access a public hot spot to watch stream videos stored on a public web site. 
     Using the current technique, the stations  110 A-N receive beacons from one or more of the access points  120 A-N with multiple BSSIDs, including a persistent, uniquely-assigned BSSD used for configuration. Each of the stations  110 A-N interacts with a corresponding one of the access points  120 A-N under parameters associated a uniquely-assigned, persistent BSSID to which a station is configured. 
       FIGS. 2A-C  are diagrams illustrating reconfigurations of stations responsive to changes in conditions, according to some embodiments. Changes can be initiated by the controller  130  or the access points  120 A-N. The controller  130  has a network-wide view  200 C and the access points  120 A,  120 B and  120 N, have access point-wide views  201 ,  202  and  203 , respectfully. The access point-wide views  201 ,  202 ,  203  can be defined by a wireless radio range of respective access points while the network-wide view is not so constrained due to a wired back-end. In operation, the station  110 A is within range of both access points  120 A and  120 N which may both report to the controller  130  that frames from the station  110 A have been received. The controller  130  uses an internal algorithm, with factors such as shortest flight time, to select the access point  120 A for servicing the station  110 A. Various conditions discussed herein can affect the decision. 
     At a later point in time, in  FIG. 2B , station  110 B has changed locations such that it is within range of the access point  120 A. The controller  130 , having a network-wide view  200  is able to identify the station  110 B at its new location and continue communication with the same BSSID assigned when connected to the access point  120 B, in a manner that is transparent to the station  110 B. Separately, and in response to the change in conditions caused by the station  110 B also being serviced by the access point  120 A, the controller  130  can reduce uplink configurations specifically for the station  110 A. The two updates to the access point  120 A can be affected by updating the global look-up table and sending changes to the access point  120 A. 
     At an even later point in time, in  FIG. 2C , the station  110 A has been reassigned to access point  120 N by the controller  130 . The flight time for data packets may still be less when sent to the access point  110 A, but other conditions have triggered the change. For example, a controller can redistribute the processing load from the access point  120 A to be partially absorbed by the access point  120 N. Moreover, the access point  120 N can handle the larger demand for uplink access demand by the station  110 A, resulting in an update in uplink configurations that increases the amount of uplink access allowed by the controller  130 . Countless additional scenarios are possible. 
       FIG. 3  is a more detailed block diagram illustrating a controller  130  of the system  100 , according to one embodiment. The controller  130  comprises an access point manager  310 , a station manager  320 , a network module  330 , and radio array  340 . The components can be implemented in hardware, software, or a combination of both. 
     The access point manager  310  logs and directs activities of access points under the controller  130 , such as BSSID assignments. In one embodiment, the access point manager  310  determines global conditions that affect BSSID assignments and parameters. The station manager  320  can store and update a global look-up table that associates stations with BSSIDs, and designates some or all as virtual port BSSIDs. The network module  330  can manage higher layer network communications with external network resources. The radio array  340  represents radio frequency (RF) hardware necessary for physical channel access. 
       FIG. 4  is a more detailed block diagram illustrating an access point  120  of the system  100 , according to one embodiment. The access point  120  comprises a beacon generation module  410 , a station manager  420 , a network module  430 , and a radio array  440 . The components can be implemented in hardware, software, or a combination of both. 
     The beacon generation module  410  generates beacons with aggregated BSSIDs, including virtual port BSSIDs. The station manager  420  stores globally and/or locally-influenced parameter values, policy-based parameter values, manually configured parameter values, or the like. Parameter values for historical and predictive stations can be stored in one option. The network module  430  and the radio array  440  can all be similar to the components of the controller  130  of  FIG. 3 . 
       FIG. 5  is a sequence diagram illustrating interactions  500  between components of the system  100  of  FIG. 1 , according to one embodiment. The interactions represent wireless communications in accordance with IEEE 802.11 standards, and the like. An example of an 802.11 network packet configured for implementation herein is illustrated in  FIG. 8 . In between the interactions, methods performed within the components of  FIG. 5  are illustrated in  FIGS. 6 and 7 . The illustrated interactions  500  are not intended to be limiting. As such, the interactions  510  to  570  can be a portion of steps from a longer process. 
     Initially, at interaction  510 , the station  110  a probe request to the access point  120 , which in turn reports the request to the controller  130 , at interaction  520 . At interaction  530 , the controller  130  configures a particular one of the access point  120  to respond to the probe request at interaction  540  by sending a BSSID. The order of interactions herein can be varied, for example, interaction  530  can occur prior to interaction  510  and without the need for interaction  520 . 
     At a later point in time, at interaction  550 , one or more of the access points  120 A-N send the controller  130  local condition information. In response, at interaction  560 , the controller  130  transfer or updates parameters for the station  110  by sending information to relevant ones of the access points  120 A-N, that implement the change to the station in interaction  570  in beacons. 
     Methods for Providing Per Station Control of Multiple Stations Across Multiple Access Points ( FIG. 6-8 ) 
       FIG. 6  is a flow diagram illustrating a method  600  for providing per station control of multiple stations across multiple access points from a controller (e.g., the controller  130  of  FIG. 1 ), according to one embodiment. 
     The method  600  starts at step  610 , when uniquely-assigned and/or persistent BSSIDs and access point assignments with parameters for stations are determined. A type of BSSID can be conditioned on whether virtual port is manually or automatically enabled for a system, for a particular station, and/or for a particular station. The data can be stored in a global look-up table, or alternatively, an external database or fast response cache. 
     At step  620 , access points are configured with local look-up table data. The local look-up data can be limited to include stations that are connected, attempting to connect, were formerly connected, or are predicted to connect, to a particular access point. In other embodiments, access points retrieve or receive information as needed from a controller or other resource. 
     At step  630 , responsive to a change in conditions, a controller evaluates whether AP assignments and/or parameters should be updated. As discussed above, global information relating to network load, predicted loads, bandwidth usage, and more can be taken into consideration for updates. Consequently, in an embodiment, changes to one station can occur in response to changes in another station connected to a different access point across the network. The process continues  650  until ended  695  by, for example, a reboot, shut down, or disabling of virtual port. 
       FIG. 7  is a flow diagram illustrating a method  700  for providing per station control of multiple stations across multiple access points from an access point (e.g., the access points  120 A-N of  FIG. 1 ), according to one embodiment. 
     The method  700  starts  705 , at step  710 , when a beacon frame with aggregated BSSIDs and parameters is generated. Some or all of the BSSIDs are uniquely-assigned and/or persistent BSSIDs. Some BSSIDs may be supported by a different access point. BSSIDs preferably belong to a same class, channel and antenna connector. One example of a Multiple BSSID element  800  for beacon or probe response frames under IEEE 802.11 kvr is illustrated in  FIG. 8 . Element ID field  802  identifies the multiple BSSID value. Length  804  has a value of 1 plus the length of the extensions in units of octets. MaxBSSID Indicator  806  indicates the maximum number of BSSIDs supported, although an access point can operate with fewer. A value of n translates to 2^n stations supported, so a value of 3 indicates that 8 BSSIs are supported. The value can be manually configured by a network administrator or automatically, for example, by a controller-based or access-point based algorithm. Optional Sub-elements  808  contains zero or more sub-elements. Each of fields  802 ,  804  and  806  is one octet in size except the Optional Sub-elements  808  which can be of variable size. Other formats are possible. 
     At step  720 , beacon frames are broadcast to stations. Beacon frames advertise a presence of an access point and keeps connected stations synchronized with parameter information. The beacon frames include the aggregated BSSIDs. Each station can retrieve updated information associated with its BSSID from beacons. 
     At step  730 , connected stations are serviced. Data is sent to and received from stations according to individualized parameters set for a station, such as uplink parameters, and other custom parameters. The process ends  795 . 
     According to some IEEE 802.11 standards, EDCA provides a probabilistic-based, quality of service by grouping traffic into four access classes: voice, video, beset effort and background in respective order of priority. Frames are passed to the MAC layer from upper protocol layers with a priority value set between 0 and 7, which are used for mapping into one of the four access classes. Each class can have a separate transmission queue and medium access parameters. The values of AIFS  752 , CW  754  and others ensure priority to the medium. 
     Generic Computing Device ( FIG. 9 ) 
       FIG. 9  is a block diagram illustrating an exemplary computing device  900  for use in the system  100  of  FIG. 1 , according to one embodiment. The computing device  900  is an exemplary device that is implementable for each of the components of the system  100 , including the stations  110 A-N, the access points  120 A-N, and the controller  130 . The computing device  900  can be a mobile computing device, a laptop device, a smartphone, a tablet device, a phablet device, a video game console, a personal computing device, a stationary computing device, a server blade, an Internet appliance, a virtual computing device, a distributed computing device, a cloud-based computing device, or any appropriate processor-driven device. 
     The computing device  900 , of the present embodiment, includes a memory  910 , a processor  920 , a storage device  930 , and an I/O port  940 . Each of the components is coupled for electronic communication via a bus  999 . Communication can be digital and/or analog, and use any suitable protocol. 
     The memory  910  further comprises network applications  912  and an operating system  914 . The network applications  912  can include the modules of controllers or access points as illustrated in  FIGS. 3 and 4 . Other network applications  912  can include a web browser, a mobile application, an application that uses networking, a remote application executing locally, a network protocol application, a network management application, a network routing application, or the like. 
     The operating system  914  can be one of the Microsoft Windows® family of operating systems (e.g., Windows 95, 98, Me, Windows NT, Windows 2000, Windows XP, Windows XP x64 Edition, Windows Vista, Windows CE, Windows Mobile, Windows 7 or Windows 8), Linux, HP-UX, UNIX, Sun OS, Solaris, Mac OS X, Alpha OS, AIX, IRIX32, or IRIX64. Other operating systems may be used. Microsoft Windows is a trademark of Microsoft Corporation. 
     The processor  920  can be a network processor (e.g., optimized for IEEE 802.11), a general purpose processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a reduced instruction set controller (RISC) processor, an integrated circuit, or the like. Qualcomm Atheros, Broadcom Corporation, and Marvell Semiconductors manufacture processors that are optimized for IEEE 802.11 devices. The processor  920  can be single core, multiple core, or include more than one processing elements. The processor  920  can be disposed on silicon or any other suitable material. The processor  920  can receive and execute instructions and data stored in the memory  910  or the storage device  930   
     The storage device  930  can be any non-volatile type of storage such as a magnetic disc, electrically erasable programmable read-only memory (EEPROM), Flash, or the like. The storage device  930  stores code and data for applications. 
     The I/O port  940  further comprises a user interface  942  and a network interface  944 . The user interface  942  can output to a display device and receive input from, for example, a keyboard. The network interface  944  (e.g. RF antennae) connects to a medium such as Ethernet or Wi-Fi for data input and output. 
     Many of the functionalities described herein can be implemented with computer software, computer hardware, or a combination. 
     Computer software products (e.g., non-transitory computer products storing source code) may be written in any of various suitable programming languages, such as C, C++, C#, Oracle® Java, JavaScript, PHP, Python, Perl, Ruby, AJAX, and Adobe® Flash®. The computer software product may be an independent application with data input and data display modules. Alternatively, the computer software products may be classes that are instantiated as distributed objects. The computer software products may also be component software such as Java Beans (from Sun Microsystems) or Enterprise Java Beans (EJB from Sun Microsystems). 
     Furthermore, the computer that is running the previously mentioned computer software may be connected to a network and may interface to other computers using this network. The network may be on an intranet or the Internet, among others. The network may be a wired network (e.g., using copper), telephone network, packet network, an optical network (e.g., using optical fiber), or a wireless network, or any combination of these. For example, data and other information may be passed between the computer and components (or steps) of a system of the invention using a wireless network using a protocol such as Wi-Fi (IEEE standards 802.11, 802.11a, 802.11b, 802.11e, 802.11g, 802.11i, 802.11n, and 802.11ac, just to name a few examples). For example, signals from a computer may be transferred, at least in part, wirelessly to components or other computers. 
     In an embodiment, with a Web browser executing on a computer workstation system, a user accesses a system on the World Wide Web (WWW) through a network such as the Internet. The Web browser is used to download web pages or other content in various formats including HTML, XML, text, PDF, and postscript, and may be used to upload information to other parts of the system. The Web browser may use uniform resource identifiers (URLs) to identify resources on the Web and hypertext transfer protocol (HTTP) in transferring files on the Web. 
     This description of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications. This description will enable others skilled in the art to best utilize and practice the invention in various embodiments and with various modifications as are suited to a particular use. The scope of the invention is defined by the following claims.