Autonomic reassociation of client in a wireless local area network

The spontaneous re-association of the client in the city network of the first non-bureaucratic bureau Technical Field This invention relates to a wireless networking system, and in particular to a wireless network access point that provides a backbone network source to wireless clients. The access point can detect a degraded condition on the backbone network and notify the client of the degraded condition.

2. Description of the Related Art In the past two decades, the development of primitive computing power accompanied by the growth of computer equipment has increased at a rate. This remarkable growth, together with the emergence of the Internet, has led to a problem for other people and others. The arrival of a new era of system and information accessibility. The simultaneous explosion of information and technology integration in daily life has led to new requirements for how people manage and maintain computer systems. When looking for someone to manage complex and benevolent When it comes to the support of simple computer systems, the demand for information technology professionals has already exceeded the supply. Because access to information through personal computers, handheld devices, and wireless devices has become ubiquitous, the current infrastructure, systems, and data The stability of IT is at increasing risk of failure. This increasing complexity, together with the lack of skilled information technology professionals, indicates the inevitable need to make many things associated with todays computing Function automation · Spontaneous (eutoiioinic) calculation is a proposal to solve this technical problem. Spontaneous computing must construct a system that regulates itself in almost the same way that the human autonomic nervous system regulates and protects the human body.

In the past ten years, portable computing has been accelerating to meet the needs of mobile office. This large number of mobile offices have traditionally relied on the cable connection to the backbone network in order to access things such as printers, email servers, databases, and storage. Equipment, and even resources such as Internet connections. In just the past few years, the industry has

200480037728.6 The rapid deployment of the city network without the bureau, which provides enhanced convenience compared to the cable connection to the backbone network. In addition to the convenience, the wireless network also provides no travel while maintaining the network connection. · Recently, the wireless LAN standard called the IE£E 802.11 standard has been adopted, and it has won recognition in the industrial, scientific, and medical communities·The IEEE 802.11 standard for search-less networks is used in 2,400.The standard for systems operating in the industrial, scientific, and medical (ISM) band of 2,483.5 MHz. The ISM band is available worldwide and allows unlicensed operation of spread spectrum systems. IEEE 802.11 RF transmission uses multiple signaling schemes (modulations) at different data rates to transfer a single data packet between wireless systems. In the wireless city network, wireless clients obtain access to resources on the backbone network through the use of access points. The backbone network is generally on a wired network such as Ethernet, but it can also be a second wireless network. Or any combination of them. When the access point provides connectivity to resources directly on the wired network, the access point will especially include a wired LAN interface, a bridging function, and a wireless LAN interface in order to communicate between the wireless network and the wired network Bridged communication · Most devices use the city network without finding an office as a connection to the existing Ethernet (cable or Shao) network coverage (overlay), the existing Ethernet network plays the role of the backbone or provides access to the backbone and its resources. Generally, access points are provided in different locations to create a continuous geographic coverage range of the wireless network. Because the range of 802.11 is limited to 30, and the length of Ethernet is physically limited to 100, the office environment is generally in a different backbone Deploy several access points on it. Allocate various wireless access points to different wireless spectrums or channels to allow the wireless range to be less than 4.

The components of the access point generally include LAN interface, LAN hub, bridging function, and wireless LAN interface. Executing software to perform router and network address translation functions. For example, these components are generally used as a stand-alone unit, that is, peer-to-peer LAN, LAN The backbone, and the independent operation of the access point component as an independent peer-to-peer LAN. This independent operation allows the access point to become very flexible. However, due to this separate operation of the access point component, problems will arise. When an Ethernet backbone fails, the cashless LAN interface component of the access point provides independent

200480037728.6 The first peer-to-peer wireless LAN function continues to operate. Therefore, wireless peer-to-peer clients can share mapped drives and other resources found on the wireless network. However, users connected to the access point cannot reach the Network resources found on an Ethernet backbone. At the same time, another client in the same physical area that happens to be connected to a different access point through the second Ethernet backbone can maintain full access to the backbone resources. This The inconsistency in the availability of network resources is problematic because it increases the frustration level of users affected by the engraving and increases the computational cost as a direct result of the increase in help center calls. However, it is based on spontaneous calculations. It has been found that there are difficulties in alleviating this inconsistent network availability of the client. The content of the invention has been found that when a performance degradation state is detected on the network that plays the role of the backbone of the innocent network, the re-association request is sent to and access Point the associated one or more clients to solve the above-mentioned problem. The most effective way to realize the client's re-association request is by means of broadcasting to all clients indicating the request. However, to the clients winter re-association The association request is also valid.

Another aspect of the present invention includes the type of information contained in the re-association request. The re-association request, whether through broadcast or through individual packets, may have information about the level of performance degradation of the backbone network, and may include Useful other information. Once the client is notified of the reduced performance, the client can freely search for access to the backbone network through other access points that are available and not affected by the geographic area where the client resides. The impact of reduced performance · In a specific embodiment, in addition to transmitting a day new association request, it also reduces the rate at which the client is further associated with the wireless network. In response to detecting a reduced performance state, the association rate is reduced.

In another specific embodiment, in which the beacon is normally transmitted with a specific time to identify the availability of the access point, and in addition to transmitting the re-association request, the transmission of the beacon is suspended. In this way, the transmission of the beacon is suspended, reducing Clients attempting to gain access to resources found on the backbone network will have access to reduced performance relative to the backbone network.

200480037728.6 Opportunity to associate with the first point. In another specific embodiment, the response to the detection of a performance degradation state completely rejects the clients further association. The client actively sends a beacon in the process of attempting to associate with the access point In this case, this implementation steel is particularly useful. Brief description of the drawings Figure 1 depicts a situation in which the freezing treatment of the present invention is advantageous; Figure 2 is a block diagram of an access point configured according to an embodiment of the present invention; Figure 3 is based on the present invention block diagram of opposite client embodiment of the invention; FIG. 4 is described in maintaining and / or establishing the connection in FIG. 2 when the associated point is a flowchart of the logical receiving client implementation of FIG. 3; FIG. 5 is A flowchart showing the logic implemented by the access point in FIG. 2 according to an embodiment of the present invention; FIG. 6 is a flowchart showing the logic implemented by the access point in FIG. 2 according to an embodiment of the present invention; and FIG. 7 is a flowchart describing the logic implemented by the client in FIG. 3 when maintaining and/or establishing an association with the access point in FIG. The additional function of responding to the re-association request sent by the access point.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the present invention will be described more fully hereinafter with reference to the accompanying drawings in which preferred embodiments of the present invention are shown, at the beginning of the following description, it should be understood that those skilled in the art can modify this The invention described in the fan can still obtain the advantageous results of this invention. Therefore, the following description should be understood as a wide teaching disclosure for technicians in the city, and should not be understood as a limitation of the present invention. The description of "one embodiment", "an embodiment" or similar language in this from beginning to end means that a specific feature, structure or characteristic described in conjunction with an embodiment is included in at least one embodiment of the present invention. Therefore, throughout this The phrases "in one embodiment," "in a specific embodiment," and similar language appearing in the

20048003772 & 6 The first part is related to the same embodiment. Now referring to the drawings more specifically, Figure 1 depicts the situation in which the principle of the present invention is advantageous. The device 100 includes two access points 106 and 102, each Each access point covers the geographic area of the general pattern of 108 and 104 respectively. The access point provides access to distributed resources and services for associated wireless clients or wireless stations via wireless media. Preferably, access Points 106 and 102 include IEEE 802.11 media access control functions and a transmission layer interface to the wireless medium. Here, wireless clients 114 and 118 are used to denote various wireless clients throughout the device 100. The wireless clients 114 and 118 are generally and preferably mobile computing units such as laptop computers and palmtop computers. As mobile units, the clients 114 and 118 generally do not have printing capabilities, nor do they require too much printing. Other resources that cannot be carried by hardware. Such printing performance and other resources can be found on the backbone networks 110 and 112. According to the device 100, these backbone networks are connected to two access points 106 and 102, respectively. The access points 106 and 102 then provide these resources and services of the backbone network to the wireless network, so that these resources and services are available to the wireless clients 114 and 118. The backbone networks 110 and 112 provide the assembler 100 Distributed resources and services. These resources And services include, but are not limited to, print servers and printers, email servers, fax servers, database servers, and Internet access. Backbone networks 110 and 112 are preferably Ethernet LANs, however, alternatively, connections 110 and Π2 can be connected to No money or optical distribution scheme for the same resources and services. In addition, the backbone connections 110 and 112 can be bridged connections, which should later provide the resources and services of the backbone network. The wireless clients 114 and 118 can be configured in a dedicated mode and can be configured by This is when their respective signal strength allows direct peer-to-peer data transmission and share each others resources. Otherwise, clients 114 and 118 can reach each other through backbone networks 110 and 112; in this case, their communication will be Will pass through the access points associated with them.

2 is a block diagram of an access point configured according to an embodiment of the present invention. The access point 200 includes a wireless LAN interface 222, a bridge FIFO or flow controller 202, and a LAN interface 212. The wireless interface 222 can be any use such as RF, Infrared, VHF, UHF, and wireless interface of any wireless medium such as wave. However, in a preferred embodiment, the wireless

200480037728.6 No.

The LAN interface 222 is implemented as an 802.11-compatible wireless city network interface. The LAN interface 212 can be a wired land-based (bnd·based) network interface, an optical network interface such as a fiber optic network interface, or a set of The second wireless network interface. However, in the preferred embodiment, the LAN interface 212 is implemented as an interface for a land-based network for Ethernet. The LAN interface 212 is usually connected or bridged to a backbone network that provides resources and services. Wireless The LAN interface 222 provides resources and services found on the backbone network to the moneyless clients associated with the wireless LAN interface 222. The term "association" used here describes such a service, which is used to establish an access point to the client The mapping of the end and enables the client to call the resources and services found on the backbone network. The bridge FIFO/flow controller 202 bridges and controls between the wireless client coupled through the wireless LAN interface 222 and the backbone network coupled to the LAN interface 212 Communication flow. The flow controller 202 maintains a FIFO for the two-way communication between the interfaces 222 and 212. The flow controller 202 may be implemented entirely in hardware, or partly implemented in hardware and partly implemented in software/firmware. However, in the preferred embodiment shown in FIG. 2, the flow controller 202 is implemented using a microprocessor 210, which has a The boot code executed on 210 and the program storage device of the microcode 208. The boot code is generally executed directly from the program storage device 208, and the microcode is generally transferred to the memory 204 for faster execution. The flow control deleter 202 also includes the execution of the low-level Field-powered interface controller 206, these low-level functions include the hand bumping function required to span the interface 232 to the wireless LAN interface 222 and span the interface 234 to the LAN interface 212.The structure of the wireless LAN interface 222 includes a physical layer RF transceiver 224. The transmission FIFO 230 and the reception FIFO 228, and a low-wrinkle controller 226 for interfacing with the flow controller via the interface 232. The wireless LAN interface 222 includes antenna 233 for coupling electromagnetic energy to the air. It should be noted that the term "RF" used here is consistent with the IEEE 802.11 specification. In the entire IEEE 802.11 specification, The direct sequence spread spectrum (DSSS) system described therein is oriented to such an RF LAN system that has a 2.4 GHz band designated for industrial, scientific, and medical (ISM) applications provided in the United States under FCC 15.247 In other words, the actual modulation frequency used by the RF transceiver 224 is in the 2.4 GHz microwave ISM band instead of what is traditionally called

20048003772& 6 In the "RF" frequency band·

The structure of the LAN interface 212 includes a physical layer Ethernet transceiver 218, a transmission FIFO 220, and a reception FIFO 216. A low-compliance controller 214, an Ethernet transceiver for interfacing with the stream controller via the interface 234. 218 is coupled to the backbone network 110 or 112. The controllers 226 and 214 can be implemented in hardware, or as a combination of hardware and software/firmware components. However, in a preferred embodiment, the controllers 226 and 214 are in the form of hardware Implemented for faster operation. The wireless LAN interface 222 and the LAN interface 212 implement at least the physical and media access layer in the ISO LAN network model. The higher ISO layer is implemented in the flow controller 202. However, it is possible The higher layers of the ISO model are implemented in the interfaces 222 and 212.

More details related to the configuration and use of the access point 200 will be described with respect to the following flowchart. Certain details related to the construction and use of access points are well known in the art, and they are omitted so as not to obscure the current disclosure with unnecessary details.

Figure 3 is a block diagram of a client configured according to an embodiment of the present invention. The client 300 includes a physical layer RF transceiver 322, a transmit FIFO 328 and a receive FIFO 326, and is used to interface with other components of the client 300 through the PCI bus 310 The low-level controller 324. The wireless LAN interface 322 includes a antenna 334 for coupling electromagnetic energy to the air. The controller 300 also includes a video controller 318, which provides control signals to the video LCD display 320. The PCI master controller 308 is operatively coupled to various modules within the client 300. The standard processing part is reported to the PCI bus controller 308, and includes a microprocessor 302, a memory controller 304, and a memory 306. The processor 302 receives its boot code from the flash program storage device 316 through the PCI bus controller 308. The storage module 312 provides the client with a DASD storage device for storing application software and application data, and for storing and executing operating system code. The client 300 also includes a male disk and mouse interface 314 coupled to the PCI bus controller 308 The keyboard and mouse interface 314 accepts user input from the provided plate and pill mark. The controller 324 of the wireless LAN interface 322, or the signature processor 302 and the controller 324 can be established according to the logic shown in FIG. 4 The association and wireless connection of the access point 200 will be described in detail in the following description. However, in a preferred embodiment, the access point is completely implemented in the controller 324 according to the logic described in FIG. 4

20048003772&6 The association and wireless connection of the first entry point 200. Figure 4 is a flowchart describing the logic implemented by the client in Figure 3 when maintaining and/or establishing an association with the access point in Figure 2. Initially Starting at 400, then the client 300 scans (402) for any available access points within its geographic range and then determines (404) whether an access point is found. If it is not found, the client 300 then scans (402) for available access points. If one or more access points are found, the client 300 will associate and connect (408) to the first available access point found to be the highest in the predetermined priority list. The priority list can be determined by the user Enter, or automatically entered by the system administrator through the network during initial setup. Users will be more inclined to enter the access point they have used most of the venue to the top of the list. Often, this is the access point closest to the home where the user is usually physically camped, so by virtue of its proximity to the user, the access point provides high signal strength and gives the best The signal quality client 300 then makes a two-stage determination (410 and 412) regarding the status of the association and the link. First, it is determined (410) whether the association remains valid. If the association is not valid, the client 300 continues to scan (402) for available access points. If the association is still valid, the client 300 Determine (412) whether the link quality is acceptable. Because of many different reasons, the link quality will not remain the same, so it must be checked regularly. For example, if the client 300 is roaming, that is, whether it is by public transportation, car, If you are physically moving by walking, the signal strength of the access point will weaken as the client moves away from the access point. Alternatively, due to external electromagnetic interference, the quality of the connection may be reduced. When the link is confirmed (412) When the quality is acceptable, the client 300 maintains the association, and continuously monitors the connection status (410) and the quality boy (412). If it is determined (412) that the connection quality boy is unacceptable, the client 300 stomach Risk to leave, and scan (402) available alternative access points within its range, in an attempt to find a higher-level spam signal quality of the receiver. In the subsequent description of Figure 7 will be more technically fascinated by the client Operational characteristics of 300· Fig. 5 is a flowchart showing the logic implemented by the access point in Fig. 2 according to an embodiment of the present invention· Now referring to Figs. 1, 2 and 5, such an example will be given, which shows This shows that the backbone network 112 shown in FIG. 1 encounters a network failure or it suffers from a significantly reduced query performance status.

200480037728.6 The operation of the access point 200 in the second case. Assume that the backbone network 112 shown in FIG. 1 encounters a network failure, and it is assumed that both the clients 114 and 118 are associated with the access point 112. In this case, the client Both ends 114 and 118 will not be able to access the resources and services available on the backbone 112. However, it is still possible for the client 114 to gain access to the backbone 110 through the access point. 106. This is executing the logic shown in Figure 5 The process is achieved by the access point 200. Initially, it starts at 500, and then the access point 200 monitors (502) the data flow to and from the wired LAN. The monitoring (502) is performed by the interface setter 206 in FIG. 2 through the communication monitor 252, which monitors the LAN interface 212 in order to monitor for malfunctions or performance degradation. Alternatively, the monitoring (502) may be performed by the microprocessor 210 Executed in the form of software residing in the anchor 204. In any implementation, the status of the backbone network is monitored by recording the packet and the time required to transmit the packet to and from the backbone. When determining whether the backbone is experiencing performance degradation, compare the actual transmission time with a preset time. In addition, when determining whether there is a performance degradation state, you can compare the total bandwidth with a predetermined value. Then Make judgments about the flow through the backbone network (504) .If judged Determine (504) that the flow is acceptable, then the access point 200 maintains the status quo and monitors (502) the flow on the backbone network. If it is determined (504) that the flow is unacceptable, then set (506) the stop or delay bit in the wrinkle register 250 of the controller 226 of the wireless LAN interface 222 of FIG. 2. As an alternative to the realization of the buffer register 250, you can The stop/pause and delay described with respect to Fig. 6 are executed by the microprocessor 210 with software resident in the memory 204. See Figs. 1, 2 and 5 again, in response to the determination that the flow is unacceptable (504), and then The access point 102 sends (508) a broadcast to the clients associated with the access point 102 to request the associated clients 114 and 118 to re-associate. As an alternative to the broadcast, each re-association request can be sent to each client. Two associated clients and access points monitor (502) the data flow to and from the wired LAN to perform entertainment operations. Figure 6 shows the logic implemented by the access point in Figure 2 according to an embodiment of the present invention flow chart. Although it can be seen that the logic flow shown in Figure 6 and the logic flow shown in Figure 5 are mutually dependent, the logic flow shown in Figure 6 can be executed independently of the logic shown in Figure 5 · Start at 600 at first, and then Determine (602) whether to allow the association of a new client. In the preferred embodiment, this is done by reading the register 250 in FIG. 2 and determining whether a stop is set

200480037728. 6 The first stop is achieved. Although the stop and delay bits of the work register 250 can be set arbitrarily, in a preferred embodiment, the stop bit is set in the register 250 in the unfortunate situation where there is a total network failure. On the contrary, In the case that the performance of the backbone network is degraded and the backbone is still available, it is preferable to set a delay to invalidate the stop bit. In addition, the buffer register 250 in FIG. 2 need not be limited to one or two bits, but can be implemented as a storage Predict multiple bits of the expected delay value depending on the severity of the performance degradation detected on the backbone network. If the stop bit of the register 250 is set, no association is made, and the access point 200 simply determines (602) Whether to allow the key to proceed during the cycle of associations? If the stop bit of the register 250 is not set (invalidate or not declare), then new associations to the client are allowed, and (604) is periodically transmitted to identify the access point 200 can be used for subsequent associated beacons · In the absence of the delay bit of the register 250, beacons are transmitted at standard intervals (604) · However, if the delay bit of the register 250 is set, the beacon interval is extended In this way, depending on the state of the backbone network, new associations are completely suspended or delayed. Preferably, the association is suspended due to network failure conditions, and the association is delayed due to degraded performance. By reducing the rate at which new beacons are sent (604), the interception is increased The possibility that the target client will find another access point to associate with it. Then, the association process is continued by waiting (605) for the client to respond to the beacon. When the client responds, an attempt to authenticate the client is subsequently performed (606). It can be through the access control list (ACL), through the use of the private key /Public key, or by any other known authentication method. Usually, a simple access control list is used, in which the system administrator maintains a list of known clients that are allowed to associate with the backbone network. However, when required For a high degree of security, it is preferable to use a public key/private key encryption method. Then, according to the conclusion of the authentication attempt (606), it is determined (608) whether to associate the client. If the host is not associated, the association is not performed, and the access point 200 continues to wait (605) for the client to respond to the beacon · If it is determined (608) to associate the client, then associate the client and complete Connection to the Main Thousand Network · In Figure 6, the delay of the beacon to be sent (604) and the access point waiting (605) are mainly explained in terms of the release of the client such as the client 300 shown in Figure 3 The state in which the client responds. In the case of an active client, the active client transmits for access

20048003772& 6 The first question is to transmit the beacon instead of waiting to receive the beacon from the access point. Although the active client does not depend on the beacon sent (604), the delay is in the case of the active client Is applicable and beneficial. Alternatively, in the case of a mixture of passive and active clients, certain embodiments may include the delay currently applied in the process of sending (604) the beacon as a way to wait for (605) the client to respond to the beacon or from the active client Part of the beacon sent by the client · Figure 7 is a flowchart describing the logic implemented by the client in Figure 3 when maintaining and/or establishing an association with the access point in Figure 2, where the client in Figure 3 An additional function capable of responding to the re-association request transmitted by the access point in FIG. 2 is realized. The operation is similar to that in Fig. 4, and the additional functions in the client allow the client 300 to respond intelligently in response to the re-association request transmitted (508) in Fig. 5 · Dare to start at 700, and then the client The client 300 scans (702) for any available access points within its geographic range·and then determines (704) whether an access point is found·if not found, the client 300 then scans (702) for available access points. If one or more access points are found, the client 300 will associate and connect (708) to the The highest first available access point on the list. The priority list can be entered by the user, or automatically entered by the system administrator through the network during the initial setup. Users will be more inclined to enter the access points they have been used as venues to the top of the list. Often, this is the access point closest to where the user usually resides physically, so rely on it Proximity to the user, the access point provides the highest signal strength and gives the best signal quality. The client 300 then conducts two-stage determination of the status of the association and link (710 and 712). First, Determine (710) whether the association remains valid. If the association is not valid, then the client 300 scans (702) for available access points. If the association is still valid, the client 300 determines (712) the money access Is the quality boy acceptable? If it is determined (712) that the link quality is unacceptable, the client 300 ventures away and traces (702) alternative access points available within its range in an attempt to find a higher Level signal quality childs connection · When it is determined (712) that the link quality is acceptable, the client 300 determines (714) whether it has received a re-association request from the access point with which it is associated · If it is determined (714) still If the re-association request is not received, the client 300 keeps this off

200480037728.6, and continue to monitor the connection status (710). If it is confirmed (714) that the re-association request has been received, the client 300 f safely leaves, and scans (702) the available supervisory switch connections within its range In order to try to find an access point with a valid backbone. As described with respect to Figure 5, in the case where it is still possible for the client 114 to gain access to the backbone 110 through the access point 106, this will be used In the case of the access point 102 in FIG. 1 Continuing with this example, in response to a network failure or performance degradation state, the access point 102 will request a re-association request. When the client 114 makes the determination 714 in FIG. 7, that is, determines that it has received the re-association request from the access point 102, the client 300 ventures away, and scans (702) as an alternative access point to find available access points. Enter the point 106, and start (700) a new association cycle with the access point 106. When associating with the new access point 106, the client 114 continues to delete the association with the access point 102, which may involve a different type of re-association request initiated at the client 114 instead of at the access point. The preferred embodiments of the present invention have been illustrated in the accompanying drawings, and although specific terminology is used, the description given in this way is in a general and descriptive sense and not for limitation.

200480037728.6