USOO8045531B2
`
`(12) United States Patent
`Cheng et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 8,045,531 B2
`Oct. 25, 2011
`
`(54) SYSTEMAND METHOD FOR NEGOTIATION
`OF WLAN ENTITY
`
`(75) Inventors: Hong Cheng, Singapore (SG); Pek Yew
`Tan, Singapore (SG); Saravanan
`Govindan, Singapore (SG)
`
`(73) Assignee: Panasonic Corporation, Osaka (JP)
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 1120 days.
`
`(21) Appl. No.:
`
`10/591, 184
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`6,522,881 B1
`2/2003 Feder et al.
`6,965,605 B1 * 1 1/2005 Amos et al. ................... 370/401
`7,191,236 B2 * 3/2007 Simpson-Young et al. .. 709/228
`7,478,146 B2 *
`1/2009 Tervo et al. ................... TO9.220
`7,606,208 B2 * 10/2009 Benveniste .
`370,338
`7,697.549 B2 * 4/2010 Eran ..............
`... 370/401
`2003/0035464 A1
`2/2003 Dehner et al. ................ 375/132
`(Continued)
`
`JP
`
`FOREIGN PATENT DOCUMENTS
`10-041969
`2, 1998
`(Continued)
`
`(86). PCT No.:
`
`PCT/UP2005/003390
`
`S371 (c)(1),
`(2), (4) Date: May 14, 2007
`(87) PCT Pub. No.: WO2005/083942
`PCT Pub. Date: Sep. 9, 2005
`Prior Publication Data
`US 2007/O258.414A1
`Nov. 8, 2007
`
`(65)
`
`(30)
`
`Foreign Application Priority Data
`
`Mar. 2, 2004 (JP) ................................. 2004-058245
`Jul. 16, 2004 (JP) ................................. 2004-209470
`
`(51) Int. Cl.
`(2009.01)
`H0474/00
`(52) U.S. Cl. ........ 370/338; 370/252; 370/254; 370/328;
`370/329; 370/341; 455/412:455/435.1; 455/515;
`455/55.0.1
`(58) Field of Classification Search .................. 370/338,
`370/328,341,395.2, 395.21, 252,254, 329,
`370/330; 455/4.1.2, 502, 414.1, 435.1, 509,
`455/515,550.1
`See application file for complete search history.
`
`B. O'Hara, et al., “CAPWAP Problem Statement” draft-ietf-capwap
`problem-statement-02, CAPWAP Working Group, Internet-Draft,
`pp. 1-9, Aug. 20, 2004.
`
`(Continued)
`Primary Examiner — Olumide TAjibade Akonai
`(74) Attorney, Agent, or Firm — Dickinson Wright PLLC
`(57)
`ABSTRACT
`A method for negotiations between various entities of a wire
`less local area network (WLAN) including negotiations
`between controlling nodes (CNS) and wireless access points
`(WAPs) and negotiations between WAPs is disclosed. These
`negotiations are used for the purpose of establishing the capa
`bilities of the various entities, determining how Such capa
`bilities may be optimally divided among the negotiating enti
`ties and then dividing the capabilities among the entities
`based on this determination. The capabilities include those
`required for the operation, control and management of the
`WLAN entities and the encompassing WLAN. The disclosed
`method introduces means for flexibly accommodating the
`varying degrees of differences in capabilities among the
`WLAN entities between the WLAN entities including
`dynamic changes in WLAN topologies.
`
`16 Claims, 10 Drawing Sheets
`
`wAP contRoller Discowerschs
`
`/ 201
`
`WAP CONTROLLER CHOOSES ONE
`AMONG DiscovERED NWT witH
`CASSOCATE
`
`203
`
`/
`
`205
`WAP CONTROLLERAN CNCNTROLEER
`NEGOATE TO DETERMNEVISION OF WAN -/
`FUNCTIONALTY
`
`20
`
`-
`
`WAP CONTROLLERENIATES NEGTATIONBY SENDING
`CN CONROLLER CAPALES INFORMATIC
`(NeONTRorisatisations
`REQUESTING FORCARABIESINFORMATION FROM
`WAP CONTROLLER
`28
`encontroller determinesapyision of wan
`FUNCTIONALTYBASED ONCAPABluTES OF WAPAND K- 215
`SENS to WAp
`f
`WAP CONTROLLER SENDSNEGATWE
`ACKNWLEMENT TOs CN CONRLLER
`WTH ACTIONAL INFORMAdM
`
`2
`
`
`
`WAP CONRLERHECKS
`1FFUNCTONALITYDIVISIONSFASBLE
`AND ACCEPTABLE
`
`HECKF
`SEGOTATIONSNEECTOBE
`ERMINATD BASED
`
`yES
`
`219
`
`WAP GONTROLLERSENDS PosTVE
`ACKNOWLEDGEMENT TO CN CONTROLLER
`
`TERMINATE
`NEGOATONS
`
`- 221
`
`21
`
`CN CONTROLLERESTABLISHES PROESSNs
`SCHEDULE FORASS3CIATED WAP
`
`End C
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000001
`
`

`

`US 8,045,531 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`2003/0163579 A1* 8, 2003 Knauerhase et al. ......... TO9/230
`2005.0053005 A1* 3, 2005 Cain et al. ..........
`370,235
`2005/00593.96 A1* 3, 2005 Chuah et al. ............... 455,435.1
`
`
`
`JP
`
`FOREIGN PATENT DOCUMENTS
`2000-069050
`3, 2000
`
`OTHER PUBLICATIONS
`“Part 11: Wireless LAN Medium Access Control (MAC) and Physi
`cal Layer (PHY) Specifications.” Information Technology, Telecom
`munications and Information Exchange between systems, Local and
`Metropolitan Area Networks, Specific Requirements, ANSI/IEEE
`Std 802.11, 1999 Edition (R2003), LAN MAN Standards Committee
`of the IEEE Company Society, 528 pages total, Jun. 12, 2003.
`
`PCT International Search Report dated May 17, 2005.
`B. Ohara, et al., “Architecture for Control and Provisioning of Wire
`less Access Points (CAPWAP).” CAPWAP Working Group Internet
`Draft, Feb. 2004, pp. 1-35.
`H. Tang, et al., “Issues of the Radio Access Network with Distributed
`Radio Network Control Functions for Universal Mobile Telecommu
`nication System,” the 14th IEEE 2003 International Symposium on
`Personal, Indoor and Mobile Radio Communication Proceedings,
`Sep. 2003, pp. 931-935.
`P. Calhoun, et al., “CAPWAP Problem Statement. CAPWAP Work
`ing Group Internet-Draft, Feb. 2004, pp. 1-9.
`H. Cheng, et al., “Functionality Classifications for Control and Pro
`visioning of Wireless Access Points.” CAPWAP Internet-Draft, Feb.
`2004 pp. 1-9.
`* cited by examiner
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000002
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 1 of 10
`
`US 8,045,531 B2
`
`FIG. 1
`
`117
`
`
`
`115
`
`115
`
`115
`
`115
`
`115
`
`113
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000003
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 2 of 10
`
`US 8,045,531 B2
`
`FIG 2
`
`WAP CONTROLLER DISCOVERS CNs
`
`201
`
`WAP CONTROLLER CHOOSES ONE
`AMONG DISCOVERED CNs WITH WHICH
`TO ASSOCIATE
`
`
`
`
`
`
`
`WAP CONTROLLER AND CN CONTROLLER
`NEGOTIATE TO DETERMINE DIVISION OF WLAN
`FUNCTIONALITY
`
`2O3
`
`205
`
`WAP CONTROLLER INITATES NEGOTIATION BY SENDING
`CN CONTROLLER CAPABILITIES INFORMATION
`CN CONTROLLER INITIATES NEGOTIAION BY
`REQUESTING FOR CAPABILITIES INFORMATION FROM
`WAP CONTROLLER
`
`CN CONTROLLER DETERMINES A DIVISION OF WLAN
`FUNCTIONALITY BASED ON CAPABILITIES OF WAP AND
`SENDS TO WAP
`
`2O7
`
`209
`
`215
`
`WAP CONTROLLER SENDS NEGATIVE
`ACKNOWLEDGEMENT TO CN CONTROLLER
`WITH ADDITIONAL INFORMATION
`
`EGOTIATIONS NEED TO BE
`TERMINATED BASED
`ON POLICE
`
`
`
`
`
`YES
`
`219
`
`TERMINATE
`NEGOTIATIONS
`
`221
`
`
`
`
`
`
`
`211
`
`
`
`WAP CONTROLLER CHECKS
`IF FUNCTIONALITY DIVISION IS FEASIBLE
`AND ACCEPTABLE
`
`YES
`WAP CONTROLLER SENDS POSITIVE
`ACKNOWLEDGEMENT TO CN CONTROLLER
`
`
`
`213
`
`217
`
`CN CONTROLLERESTABLISHES PROCESSING
`SCHEDULE FOR ASSOCIATED WAP
`
`END
`
`
`
`
`
`
`
`
`
`
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000004
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 3 of 10
`
`US 8,045,531 B2
`
`FIG. 3
`
`307
`
`
`
`3O7
`
`307
`
`3.11
`
`N CN CONTROLLER
`
`307
`
`307
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000005
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 4 of 10
`
`US 8,045,531 B2
`
`
`
`[07
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000006
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 5 of 10
`
`US 8,045,531 B2
`
`FIG. 5
`
`
`
`
`
`503
`
`START
`
`5O1
`
`MONITOR nASP PROCESSING
`LOAD
`
`CHECK IF AGGREGATE nASP LOAD
`FACTOR EXCEEDS nASP LOAD THRESHOLD
`
`
`
`YES
`DETERMINE WHICH PARTS OF nASP PROCESSING LOAD CAN BE
`DISTRIBUTED TO OTHER WAPs WHILE MANTAINING EXISTING
`ASSOCIATIONS WITH MTS
`
`SEND SOLICITATION MESSAGES TO OTHER WAPs TO DETERMINE WHICH
`ARE AGREEABLE TO PROCESS DETERMINED PARTS OF nASP
`PROCESSING LOAD
`
`ESTABLISH TUNNEL CONNECTION WITH AGREEABLE WAPS AND
`TRANSFER nASP PROCESSING LOAD RELEVANT CONTEXT
`INFORMATION IF NECESSARY
`
`505
`
`507
`
`509
`
`DISTRIBUTE DETERMINED PARTS OF nASP PROCESSING LOAD TO
`WAPS WITH WHOM TUNNEL CONNECTIONS HAVE BEEN
`ESTABLISHED
`
`511
`
`END
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000007
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 6 of 10
`
`US 8,045,531 B2
`
`S.
`S
`
`s
`
`S.
`
`S
`N
`1.
`
`Ot
`DI
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000008
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 7 of 10
`
`US 8,045,531 B2
`
`
`
`
`
`5
`
`-
`
`o
`2
`a
`2 O d
`
`O
`
`s
`
`s
`
`&
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000009
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 8 of 10
`
`US 8,045,531 B2
`
`
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000010
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 9 of 10
`
`US 8,045,531 B2
`
`917
`
`WAP2
`
`95
`
`905
`
`FIG. 9
`
`909
`
`
`
`FRAME TYPE
`
`ACTION
`
`
`
`
`
`FRAME FOR ACK
`
`DATA FRAMES
`
`SIGNAL PROTOCOLCNTRL
`SEND TO
`TRANSMISSION BLOCK
`
`MANAGEMENT FRAMES PROCESS LOCALLY
`
`
`
`CONTROL FRAMES
`
`PROCESS LOCALLY
`
`913
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000011
`
`

`

`U.S. Patent
`
`Oct. 25, 2011
`
`Sheet 10 of 10
`
`US 8,045,531 B2
`
`FIG 10
`
`START
`
`1000
`
`1001
`
`NETWORK TOPOLOGY MONITORED
`
`1003
`
`NETWORK TOPOLOGY CHANGE?
`
`NO
`
`YES
`NETWORKENTITY ACCOMMODATING TOPOLOGY
`CHANGE TRIGGERED WITH "OPERATIONAL
`ASSOCATIONS' SIGNAL
`
`NETWORKENTITY ACCOMMODATING TOPOLOGY
`CHANGE TRIGGERED WITH "OPERATIONS
`UPDATE SIGNAL
`
`NETWORKENTITY EFFECTING TOPOLOGY CHANGE
`TRIGGERED WITH "OPERATIONAL ASSOCATIONS
`REGUEST SIGNAL
`
`NETWORKENTITY ACCOMMODATING TOPOLOGY
`CHANGE TRIGGERED WITH "OPERATIONAL
`ASSOCIATIONS UPDATE SIGNAL
`
`1005
`
`1007
`
`1009
`
`101
`
`1013
`
`NETWORKENTITY EFFECTING TOPOLOGY CHANGE
`TRIGGERED WITH "OPERATIONS UPDATE SIGNAL
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000012
`
`

`

`US 8,045,531 B2
`
`1.
`SYSTEMAND METHOD FOR NEGOTATION
`OF WLAN ENTITY
`
`TECHNICAL FIELD
`
`The present invention relates to the field of wireless local
`area networks and in particular to the operation of Such net
`works in heterogeneous environments.
`
`BACKGROUND ART
`
`10
`
`2
`These problems refer to static differences between WLAN
`entities as they are results of differences in basic design. In
`addition to these, there are also problems related to dynamic
`differences between WLAN entities.
`In particular, during the functioning of a WLAN, the pro
`cessing load at a WAP can become substantially high even
`exceeding the processing capacity of the WAP. This could be
`due to increases in the number of associated mobile terminals
`(MTs) or due to increases in the volume of traffic from the
`associated MTs. These differences in processing load over
`time constitute a dynamic factor as they are dependent on the
`dynamics of the MTs.
`These dynamic differences in processing load across the
`WAPs consisting of a WLAN have traditionally been
`addressed by affecting handovers of MTs from their associ
`ated WAPs where processing load is high, to re-associate the
`MTs with other WAPs where processing load is relatively
`low.
`Patent Document 1 discloses means for addressing
`dynamic differences in the levels of processing load at WAPs
`by means of proactive handovers of associated MTs. While
`Patent Document 1 addresses the problem of dynamic dif
`ferences in processing loads across WAPs, it does so by
`mandating that MTs associated with one WAP also be within
`the coverage areas of other WAPs so as to be able to perform
`handovers and re-associations. If a MT is not within the
`coverage area of one or more other assisting WAPs, it is then
`expected to physically displace to Such a coverage area in
`order to relieve the first WAP of some processing load. These
`constraints are rigid and limit the efficacy of Patent Docu
`ment 1. Such limitations are common to all handover-based
`methods.
`Patent Document 2 presents a method for WAPs to
`modify, based on prevailing processing load levels, the inter
`vals between the beacon signals that they transmit in order to
`attract or dissuade MT associations. This method also
`involves the constraints of requiring a MT to be within the
`coverage areas of alternate WAPs where processing load is
`low or being agreeable to displace towards such areas.
`Patent Document 3 focuses on proactive MTs that make
`association decisions. However the method is also limited by
`the factors described earlier.
`While such methods attempt to solve the problem of
`dynamic differences in processing load, they do so by intro
`ducing stringent prerequisites and thereby introduce more
`problems. Another shortcoming of Patent Document 1.
`Patent Document 2, Patent Document 3 and other han
`dover-based methods for dealing with dynamic differences in
`WAPs is related to the bulk shifting of communication ses
`sions. In practice MTS maintain a number of communication
`sessions with the WAPs with which they are associated. As a
`result, it is very likely that the communication sessions of
`only one MT or a few MTs constitute a considerable amount
`of processing load at the WAP. If the WAP were to affect the
`said MTs to handover and re-associate with another WAP, the
`processing load at the first WAP would be reduced, however
`by adversely affecting the other WAP. The other WAP then
`becomes overloaded and reverses the handover to the first
`WAP. This may continue without delivering any net gains for
`the WLAN. This points out that the processing load is not
`finely distributed by methods of handovers. In other words,
`dynamic differences are not finely managed.
`Non Patent Document 1 Institute of Electrical and Elec
`tronics Engineers Standard 802.11-1999 (R2003)
`Non Patent Document 2 “CAPWAP Problem State
`ment, draft-ietf-capwap-problem-statement-02.txt
`
`15
`
`Wireless local area networks (WLANs) have invoked great
`interests from both consumers and the industry. The current
`most popular WLANs are based on the Non Patent Docu
`ment 1 standards. While these standards have helped the
`initial uptake of WLANs, in their current form, they are not
`Suited for large-scale wireless network deployments. This is
`because the cost and control of WLAN entities become com
`plex in large environments.
`Currently, many WLAN equipment manufacturers have
`addressed large-scale deployments by introducing new split
`architecture. Here, control aspects of the Non Patent Docu
`ment 1 WLAN specifications are centralized at controller
`nodes (CNs) while other aspects are distributed to numerous
`wireless access points (WAPs). With the diversity of manu
`25
`facturers and their implementations of the split architecture,
`there are incompatibilities between WLAN entities from dif
`ferent manufacturers.
`There are currently some efforts to provide standardized
`means for managing large-scale WLANs in the Internet Engi
`30
`neering Task Forces (IETF) Control and Provisioning of
`Wireless Access Point (CAPWAP) working group. Non
`Patent Document 2 describes the efforts of the CAPWAP
`working group. However these efforts do not consider the
`problems of accommodating WAPs with dissimilar func
`tional capabilities within a single WLAN. As such these prob
`lems limit the development of the WLAN market.
`Furthermore, it is expected that future deployments of
`WLANs will feature dynamic wireless networks. In such
`types of deployments, network topologies will change during
`the operational lifecycle of the WLAN to enable enhanced
`applications and services. WLAN elements in such networks
`will be provisioned with both wired and wireless connectivity
`to enable dynamic topologies. However current assumptions
`of WLANs (and also CAPWAP) only refer to static network
`topologies. So while current WLANs are capable of adjusting
`to the dynamic conditions of the wireless medium, they are
`unable to accommodate the effects of dynamic topology
`changes.
`For example, current WLAN systems adjust to declines in
`the signal-to-interference ratio (SIR) of the wireless medium
`by increasing the signal transmission power. However Such
`minor corrections are inadequate to accommodate the Vari
`ances in latency and overhead introduced by changes in
`WLAN topology. Furthermore, these variances in latency and
`overhead impede the operation of the CAPWAP split archi
`tecture. This is because the split architecture is sensitive to
`delays due to the very nature of the distributed operations.
`The redundancies of WLAN and CAPWAP processing per
`formed at intermediate wireless access points (WAP) of a
`dynamic CAPWAP topology together with the corresponding
`physical overheads are detrimental to the CAPWAP split
`operations.
`Given such scenarios, WLAN entities currently available
`from various vendors are incapable of interoperation in a
`single WLAN and are also incapable of operation in a
`dynamic topology WLAN.
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`Exhibit 1001
`Hewlett Packard Enterprise Company v. Sovereign Peak Ventures, LLC
`Page 000013
`
`

`

`US 8,045,531 B2
`
`3
`Patent Document 1 "Method and apparatus for facilitat
`ing handoff in a wireless local area network, US 2003/
`OO3.5464 A1
`Patent Document 2 “Dynamically configurable beacon
`intervals for wireless LAN access points”, US 2003/0163579
`A1
`Patent Document 3 "Method and apparatus for selecting
`an access point in a wireless network, U.S. Pat. No. 6,522,
`881 B1
`
`DISCLOSURE OF THE INVENTION
`
`4
`aspect of the present invention overcomes the limitations of
`handover-based methods for managing dynamic differences
`between WLAN entities.
`In its broadest aspect, the present invention provides a
`system for providing service in a WLAN whereby a control
`node negotiates with WAPs and provides similar or different
`complimentary functionality for each of the WAPs to form a
`complete functionality defined for the WLANs.
`In its preferred form, the present invention allows for a
`controller module for control nodes to comprise a single or
`plurality of processing schedules composed of sequential lists
`of descriptors for subsets of functional components used for
`each wireless access point.
`In another preferred form, the present invention provides a
`method for providing services in a WLAN wherein a control
`node dynamically discovers the capability of a WAP by send
`ing a single or plurality of messages to a WAP containing a
`section that emulates the data unit sent by a mobile terminal,
`a WAP receiving said message processes said section using
`the same procedure for processing data units received from a
`mobile terminal and sends it back to said control node in a
`reply message and said control node obtaining capabilities
`information of said WAP by examining the processed data
`units in the reply message.
`In another preferred form, the present invention allows a
`method for providing service in a WLAN that allows defined
`WLAN function split between WAPs and one or more control
`nodes wherein a subset of WAPs processes the total of their
`subset of functionality defined for the WLAN, a control node
`provides distinct Subsets of complementary functionality
`defined for the WLAN to each of the Subset of WAPs.
`In yet another preferred form, the present invention allows
`for means for determining a flexible division in WLAN func
`tionality between the negotiating entities. The present inven
`tion first involves classifying the functional capabilities of
`WLAN entities. The entities then determine the capabilities
`of other entities followed by negotiations between them on
`how best to divide the functionality among them. Further
`operations of the WLAN entities are then based on the deter
`mined division of functionality.
`In another aspect, the present invention provides a system
`for load-balancing in a WLAN without requiring association
`handover at a mobile terminal whereby a data unit for a
`mobile terminal is processed with the complete WLAN func
`tions by a single of plurality of WAPs where each WAP
`processes the data unit with only a subset of complete WLAN
`functions.
`In its preferred form, the present invention allows for a
`method of carrying out load balancing in a WLAN without
`requiring a mobile terminal to change association relation
`ship with a WAP wherein the WAP separates the processing
`functions provided to the mobile terminal into an association
`specific part and a non-association specific part, the WAP
`negotiates with another WAP to process the non-association
`specific part and establishes a secure tunnel with the another
`WAP, the WAP tunnels a data unit from a mobile terminal to
`the another WAP through the tunnel after processing the data
`unit with the association specific part of functions and the
`another WAP receiving the processed data unit through the
`tunnel and processing it with non-association part of the
`functions.
`In another preferred form, the present invention provides a
`method for determining the distribution of non-association
`specific functions based on information comprising the size
`of the data unit to be processed, the expected average time for
`processing a data unit, the overhead time for processing a data
`unit or a weighted Sum of said information.
`
`5
`
`10
`
`15
`
`25
`
`35
`
`50
`
`55
`
`60
`
`30
`
`In view of the above discussed problems, it is the objective
`of the present invention to provide an apparatus and method
`for negotiations between controlling nodes (CNs) and wire
`less access points (WAPs) of a WLAN based on policies that
`allow for accommodating static and dynamic differences
`among the WLAN entities including dynamic changes in
`WLAN topologies within a single WLAN.
`It is another objective of the present invention to provide a
`method and policy for negotiations between WLAN entities
`for the purpose of determining selected Subsets of functional,
`load or other components to be processed by each of said
`WLAN entities so as to accommodate variations in system
`design, processing load or network topology.
`It is another objective of the present invention to provide an
`apparatus and method for negotiations between WLAN enti
`ties based on polices that allow for accommodating the
`dynamic differences between them such as differences in
`processing load levels at various WLAN entities within a
`single WLAN.
`It is yet another objective of the present invention to pro
`vide means for accommodating the operations of split archi
`tecture WLANs in the presence of dynamically changing
`network topologies.
`The disclosed invention relates to wireless local area net
`works (WLANs) and particularly to means of addressing the
`issues of static and dynamic differences among WLAN enti
`ties. It introduces policies for negotiations between WLAN
`40
`entities for the purpose of accommodating these differences.
`One aspect of the present invention deals with negotiations
`between controlling nodes (CNS) and wireless access points
`(WAPs) of a WLAN based on policies that allow for accom
`modating static differences among them. Specifically, it pre
`45
`sents means for determining a flexible division in WLAN
`functionality between the negotiating entities. The present
`invention first involves classifying the functional capabilities
`of WLAN entities. The entities then determine the capabili
`ties of other entities followed by negotiations between them
`on how best to divide the functionality among them. Further
`operations of the WLAN entities are then based on the deter
`mined division of functionality. This aspect of the present
`invention enhances interoperability for WLAN entities.
`Another aspect of the present invention deals with nego
`tiations between WLAN entities based on polices that allow
`for accommodating the dynamic differences between them.
`Particularly, it addresses the issue of distributing processing
`load among WAPs without requiring physical displacement
`of associated mobile terminals (MTs). It involves first deter
`mining the need to distribute parts of processing load at a
`WAP. This is followed by the determination of which parts of
`processing load may be distributed while at the same time
`maintaining existing association relationships between MT
`and WAP. Next, an overloaded WAP enters into negotiations
`65
`with other WAPs in order to determine how the determined
`parts of processing load may be distributed among them. This
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`5
`In another aspect, the present invention provides a method
`for accommodating variances in a wireless network topology
`wherein the method comprises the step of dynamically adapt
`ing the operations logic of at least one network entity of the
`wireless network topology to alter processing of one or more
`functional Sub-components.
`In its preferred form, the present invention allows for a
`method of accommodating variances in a WLAN by altering
`the processing of selected functional Sub-components at least
`one network entity by means of bypassing processing of said
`selected functional Sub-components.
`In its preferred form, the present invention allows for a
`method of accommodating variances in a WLAN by altering
`the processing of selected functional Sub-components at least
`one network entity by means of selectively processing said
`selected functional Sub-components.
`In another preferred form, the present invention provides a
`method for altering local-level functional semantics while
`maintaining system-wide functional semantics of a wireless
`network by selectivity activating functional Sub-components
`of selected network entities such that the sum of activated
`functional Sub-components across said wireless network cor
`responds to complete functional Sub-components of said
`wireless network.
`In yet another preferred form, the present invention pro
`vides a method for altering local-level functional Semantics
`while maintaining system-wide functional Semantics of a
`wireless network by means of shifting the processing of said
`activated functional Sub-components from a first network
`entity to a second network entity.
`Based on the aspects and preferred forms of the present
`invention, the problem of incompatibility of WAPs of differ
`ent functional capabilities is solved. The present invention
`also solves the problem of WLAN operations in dynamic
`topology environments. In yet another aspect, the present
`invention solves the problem of accommodating dissimilar
`Volumes of processing loads over time.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a diagram illustrating an operational representa
`tion of a wireless local area network (WLAN) system used to
`illustrate a first aspect of the disclosed invention dealing with
`policies for negotiations between WLAN entities, particu
`larly between a controlling node (CN) and wireless access
`points (WAPs):
`FIG. 2 is a diagram depicting the general operational steps
`involved in a first aspect of the present invention dealing with
`policies for negotiations between a CN and WAP:
`FIG. 3 is a diagram showing an integrated WLAN entity
`exemplifying one embodiment of a first aspect of the present
`invention in which the capabilities of a CN and WAP are
`integrated into one entity;
`FIG. 4 is a diagram illustrating a simplified framework for
`a second aspect of the present invention dealing with policies
`for negotiations for the purpose of accommodating dynamic
`differences among WLAN entities, particularly between
`WAPs;
`FIG. 5 is a diagram depicting the general operational steps
`involved in a second aspect of the present invention dealing
`with policies for negotiations for accommodating dynamic
`differences among WLAN entities. Specifically, it deals with
`processing loads at various entities;
`FIG. 6 is a diagram serving to explain the reasoning for one
`embodiment of a second aspect of the present invention,
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`US 8,045,531 B2
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`6
`wherein the definition of processing load is taken to be the
`size of the protocol data unit (PDU) that is received by the
`WAP from associated MTs;
`FIG. 7 is a diagram illustrating one embodiment of a sec
`ond aspect of the present invention in which a central con
`troller performs a Supervisory role in the negotiations for
`accommodating dynamic differences among WLAN entities;
`FIG. 8 is a diagram illustrating one embodiment of a first
`aspect of the present invention in which negotiations strate
`gies are applied to enable CAPWAP split operations in
`dynamic WLAN topologies:
`FIG. 9 is a diagram exemplifying a particular embodiment
`of a first aspect of the present invention relating to
`IEEE802.11 WLAN specifications; and
`FIG. 10 is a diagram depicting a sequence of steps of a first
`aspect of the present invention in which dynamic WLAN
`topologies are enabled.
`
`BEST MODE OF CARRYING OUT THE
`INVENTION
`
`The disclosed invention of policies for negotiations
`between entities of a wireless local area network (WLAN) is
`described in two major aspects, the first focusing on negotia
`tions for accommodating static differences among WLAN
`entities also comprising accommodating changes in WLAN
`topologies. While the second aspect illustrates means of deal
`ing with dynamic differences, particularly in levels of pro
`cessing load.
`In the following description, for purpose of explanation,
`specific numbers, times, structures, and other parameters are
`set forth in order to provide a thorough understanding of the
`present invention. However, it will be apparent to anyone
`skilled in the art that the present invention may be practiced
`without these specific details.
`Negotiations for Accommodating Static Differences:
`A WLAN system embodying a first aspect of the present
`invention dealing with accommodating static differences
`among WLAN entities is exemplified in FIG.1. The diagram
`illustrates a WLAN system 100 comprising a controller node
`(CN) 101, a number of wireless access points (WAPs) 105
`and 107, a plurality of mobile terminals (MTs) 113 and a
`network backbone 117. For the sake of simplicity, the WLAN
`system 100 is shown with a single CN whereas the system
`embodying the present invention may comprise any number
`of CNS. Also, the diagram indicates a direct connection
`between CN 101 and the WAPs 105 and 107. Alternatively
`there may be a number of intermediate nodes between them.
`Similarly, the connection between CN 101 and the network
`backbone 117 may also include a number of intermediate
`nodes. In all Such cases, the disclosed invention holds scope.
`The CN 101 provides support and control to the WAPs 105
`and 107 that associate with it. A new WAP in the WLAN
`system must first choose and establish association relation
`ships with one or more CNS before it receives support and
`control from the one or more CNs. As such, WAPs may
`simultaneously hold more than one association relationship
`with one or more CNs. Similarly, the MTS 113 choose and
`maintain associations with the WAPs, which in turn provide
`them with services. These services include radio transmission
`and reception, secure transport and mobility. An MT may
`maintain a number of associations with one or more WAPs,
`however FIG. 1 simplifies this with each MT maintaining
`only one association with one WAP.
`It can be inferred about the WLAN system 100 that the
`WAPs connect to the network backbone via the CN. Alterna
`tives to this include the WAPs connecting to the network
`
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`25
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`7
`backbone by other means possibly through otherintermediate
`nodes. In such cases, the CN will only be responsible for the
`control and management of the WAPs associated with it,
`while connectivity to an external network may be handled by
`other entities.
`FIG. 1 shows the CN 101 capable of performing the com
`plete set of WLAN functional operations, as specified by
`some established WLAN standard. It is also capable of other
`control and management functional operations. Each func
`tional operation is logically represented by one of the func
`tional components 115. The operations represented by each
`of the functional components may include encryption,
`decryption, medium access control protocol data unit (MAC
`PDU) processing, authentication, association, quality of Ser
`Vice (QoS) processing, Internet Protocol (IP) processing etc.
`Each functional component is represented by a functional
`component code. For the purpose of illustration, some of the
`functional components in FIG. 1 are represented by func
`tional component codes a, b and c'. For example func
`tional component a may denote