U.S. patent application number 13/930541 was filed with the patent office on 2013-11-07 for automatic detection of wireless network type.
The applicant listed for this patent is Microsoft Corporation. Invention is credited to Mohammad Shabbir Alam, Jean-Pierre Duplessis, Anton W. Krantz, Sean Lyndersay, Timothy M. Moore, Ashwin Palekar.
Application Number | 20130298204 13/930541 |
Document ID | / |
Family ID | 34465787 |
Filed Date | 2013-11-07 |
United States Patent
Application |
20130298204 |
Kind Code |
A1 |
Duplessis; Jean-Pierre ; et
al. |
November 7, 2013 |
Automatic Detection of Wireless Network Type
Abstract
Techniques for facilitating automatic detection of a type of
wireless network are described. In accordance with one or more
embodiments, wireless network client(s) can automatically detect
the "type" of a network (e.g., method of authentication and
encryption) without requiring input from the user. In accordance
with one or more embodiments, a wireless network detection system
having a connection component and a detection component is
provided. The connection component facilitates connection of a
client system to at least one of a plurality of wireless networks.
The detection component identifies a type of an available wireless
network. Identification can be based, for example, upon information
received in an information element and/or iterative probing of the
wireless network beacon.
Inventors: |
Duplessis; Jean-Pierre;
(Redmond, WA) ; Lyndersay; Sean; (Mountain View,
CA) ; Krantz; Anton W.; (Kirkland, WA) ; Alam;
Mohammad Shabbir; (Redmond, WA) ; Palekar;
Ashwin; (Sammamish, WA) ; Moore; Timothy M.;
(Bellevue, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Microsoft Corporation |
Redmond |
CA |
US |
|
|
Family ID: |
34465787 |
Appl. No.: |
13/930541 |
Filed: |
June 28, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12403851 |
Mar 13, 2009 |
8477943 |
|
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13930541 |
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10729209 |
Dec 5, 2003 |
7505596 |
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12403851 |
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Current U.S.
Class: |
726/4 |
Current CPC
Class: |
H04W 48/16 20130101;
H04W 84/12 20130101; H04L 63/20 20130101; H04W 12/0609 20190101;
H04W 12/04033 20190101; H04L 63/205 20130101; H04L 63/0428
20130101; H04L 63/06 20130101 |
Class at
Publication: |
726/4 |
International
Class: |
H04W 12/06 20060101
H04W012/06 |
Claims
1. An apparatus comprising: one or more processors; and one or more
computer-readable storage media storing computer-executable
instructions that are executable by the one or more processors to
cause the apparatus to perform operations comprising: attempting to
connect to a wireless network via a first wireless connection
protocol that supports 802.1x authentication; monitoring for a
failure associated with said attempting; responsive to ascertaining
that the failure occurs, determining that the network requests user
entry of an encryption key according to a second wireless
connection protocol; or responsive to ascertaining that the failure
does not occur, determining that the wireless network supports the
first wireless connection protocol; and displaying a user interface
based on which of the first network connection protocol or the
second network connection protocol is supported by the wireless
network.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of and claims priority to
U.S. application Ser. No. 12/403,851, filed on Mar. 13, 2009, which
is a continuation of and claims priority to U.S. application Ser.
No. 10/729,209, now issued as U.S. Pat. No. 7,505,596, filed on
Dec. 5, 2003, the disclosures of which are incorporated in their
entirety by reference herein.
BACKGROUND
[0002] Computer device(s) performing network communications over
wireless links are becoming increasingly popular. Conventionally,
when a user comes within range of a wireless network, the client
device (e.g., computer system) is able to discern two pieces of
information about that network, without connecting to it (e.g.,
from the wireless network beacon): (1) the service set identifier
(SSID) of the network (e.g., essentially its name); and, (2)
whether or not the network encrypts data. If the network employs
encryption, an encryption key is required. The encryption key can
be manually entered by the user and/or sent in accordance with the
802.1x protocol.
[0003] With the information that the client device can retrieve
from the wireless network beacon, the client device can generally
determine whether the network is of type unencrypted, encrypted or,
with the addition of a Wi-Fi Protected Access (WPA) information
element, encrypted using WPA-pre-shared key or encrypted using WPA.
If it is unencrypted, then a user needs only to acknowledge that
the network is insecure, and that they wish to use it in spite of
that information. However, if it is encrypted and does not use WPA,
then it either requires the user to enter a WEP key or it is an
802.1x-enabled network which distributes the WEP key automatically
(requiring the client computer to enable 802.1x authentication to
complete the connection).
[0004] Since the client computer cannot tell whether the non-WPA
encrypted network requires the user to enter a WEP key or is an
802.1x-enabled network which does not support WPA, it typically
requests input from the user. In the vast majority of cases, the
user is in no position, from a technical knowledge perspective, to
answer such a request.
SUMMARY
[0005] This Summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the Detailed Description. This Summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used as an aid in determining the scope of
the claimed subject matter.
[0006] Embodiments provide for a system and method facilitating
automatic detection of a type of wireless network. In accordance
with one or more embodiments, wireless network client(s) can
automatically detect the "type" of a network without requiring
input from the user. The "type" in this context, refers to the
method of authentication and encryption that the network requires
(e.g., unencrypted networks requiring no authentication, encrypted
networks requiring the user to enter a WEP key, encrypted networks
supporting 802.1x authentication, Wi-Fi Protected Access (WPA)
networks requiring the user to enter a WPA pre-shared key, 802.1x
enabled network which do support WPA, and/or wireless provisioning
services supporting networks). Thus, the system employs a technique
for efficiently and safely determining which of the network types
the user is attempting to connect to, thereby allowing the
operating system to present the user with an appropriate user
interface. For example, the system can provide a way to distinguish
whether (1) a manually-entered WEP key or (2) 802.1x authentication
is required by the wireless network.
[0007] In accordance with one or more embodiments, a wireless
network detection system having a connection component and a
detection component is provided. The connection component
facilitates connection of a client system to at least one of a
plurality of wireless networks. The detection component identifies
a type of an available wireless network.
[0008] In one example, identification by the detection component
can be based, at least in part, upon receipt of a specific
information element from a wireless network beacon. In another
example, the detection component iteratively probes the wireless
network beacon in connection with identifying a type of the
wireless network.
[0009] For example, the detection component can first attempt to
connect to the wireless network as if it were a wireless
provisioning services (WPS) supporting network. By waiting for
certain kinds of failure(s) in the authentication sequence, the
detection component can determine if the network requires the user
to enter a WEP key.
[0010] If the failures are not observed, the detection component
can wait a longer period of time (e.g., up to thirty seconds) for a
particular piece of the authentication sequence (e.g., Protected
extensible authentication protocol-type length value (PEAP-TLV))
that identifies a WPS network. In the absence of this piece of the
sequence, the detection component can identify the wireless network
as an 802.1x-enabled network to the connection component. If the
particular piece of the authentication sequence is detected by the
detection component, then the detection component can identify the
network as a WPS supporting network to the connection
component.
[0011] Accordingly, the user is not asked to determine the network
type. This can lead, for example, to user(s) who are more
successful in their use of wireless networks and further reduce
user frustration with wireless network(s).
[0012] To the accomplishment of the foregoing and related ends in
accordance with one or more embodiments, certain illustrative
aspects are described herein in connection with the following
description and the annexed drawings. These aspects are indicative,
however, of but a few of the various ways in which the principles
of various embodiments may be employed, and embodiments are
intended to include all such aspects and their equivalents. Other
advantages and novel features of the embodiments may become
apparent from the following detailed description when considered in
conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a block diagram of a wireless network detection
system in accordance with one or more embodiments.
[0014] FIG. 2 is a block diagram of example wireless network types
in accordance with one or more embodiments.
[0015] FIG. 3 is a flow chart of a method facilitating wireless
network detection in accordance with one or more embodiments.
[0016] FIG. 4 is a flow chart of a method facilitating wireless
network detection in accordance with one or more embodiments.
[0017] FIG. 5 is a flow chart further illustrating the method of
FIG. 4 in accordance with one or more embodiments.
[0018] FIG. 6 illustrates an example operating environment in which
one or more embodiments may function.
DETAILED DESCRIPTION
[0019] Embodiments are described with reference to the drawings,
wherein like reference numerals are used to refer to like elements
throughout. In the following description, for purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of various embodiments. It may be
evident, however, that embodiments may be practiced without these
specific details. In other instances, well-known structures and
devices are shown in block diagram form in order to facilitate
describing various embodiments.
[0020] As used in this application, the terms "component,"
"handler," "model," "system," and the like are intended to refer to
a computer-related entity, either hardware, a combination of
hardware and software, software, or software in execution. For
example, a component may be, but is not limited to being, a process
running on a processor, a processor, an object, an executable, a
thread of execution, a program, and/or a computer. By way of
illustration, both an application running on a server and the
server can be a component. One or more components may reside within
a process and/or thread of execution and a component may be
localized on one computer and/or distributed between two or more
computers. Also, these components can execute from various computer
readable media having various data structures stored thereon. The
components may communicate via local and/or remote processes such
as in accordance with a signal having one or more data packets
(e.g., data from one component interacting with another component
in a local system, distributed system, and/or across a network such
as the Internet with other systems via the signal). Computer
components can be stored, for example, on computer readable media
including, but not limited to, an ASIC (application specific
integrated circuit), CD (compact disc), DVD (digital video disk),
ROM (read only memory), floppy disk, hard disk, EEPROM
(electrically erasable programmable read only memory) and memory
stick in accordance with one or more embodiments.
[0021] Referring to FIG. 1, a wireless network detection system 100
in accordance with one or more embodiments is illustrated. The
system 100 can facilitate automatic detection of a type of wireless
network by a client (e.g., without requiring input from a
user).
[0022] "Type" of wireless network refers generally to the kind of
authentication and encryption that the network requires. In one
example, wireless networks can be divided into six types: [0023]
(1) Unencrypted (e.g., open) networks which generally require no
authentication. [0024] (2) Wired equivalent privacy (WEP) encrypted
networks where the user needs to enter a WEP key [0025] (3) Wi-Fi
Protected Access (WPA) encrypted network where the user needs to
enter a WPA pre-shared key (WPAPSK) [0026] (4) 802.1x-enabled
networks that do not support WPA. [0027] (5) 802.1x-enabled
networks that do support WPA [0028] (6) Wireless provisioning
services (WPS) supporting-enabled networks that do or do not
support WPA
[0029] The IEEE 802.11 set of standards defines two network types:
encrypted networks (e.g., WEP networks) and unencrypted networks.
Owing to the well-known weaknesses of the WEP protocol, the
wireless industry implemented support for the IEEE 802.1x standard
as a mechanism for addressing the key deficiencies in the WEP
protocol, those being user authentication, encryption key
management and encryption key distribution. For WEP-encrypted
networks, the user needs to provide an encryption key and for
802.1x enabled networks the key is provided automatically if the
user has a valid credential (e.g., such as a digital certificate or
username and password). For 802.11 networks which are encrypted,
this presents a usability problem as it is currently not possible
to determine a priori whether the user needs to enter the WEP key
or whether the network supports 802.1x, in which case they do not
have to enter it.
[0030] To address the underlying weaknesses of the WEP algorithm,
which has been shown to be cryptographically weak, a security
enhancement to the 802.11 set of standards was introduced, called
Wi-Fi Protected Access (WPA). WPA also addresses some of the
usability issues of the original 802.11 standard by specifying an
information element which WPA-capable access points include in
their beacon frame. This information element describes inter alia
whether the network requires the user to enter the encryption key
called WPA pre-shared key mode (WPA-PSK) or whether the key is
provided automatically by virtue of the user's credential, referred
to as "WPA mode".
[0031] Having presented an overview of example implementations in
accordance with one or more embodiments, consider now an example
environment in which example implementations may by employed.
[0032] Wired Equivalent Privacy
[0033] WEP is defined by the IEEE 802.11 standard and is intended
to provide a level of data confidentiality that is equivalent to a
wired network. Due to the nature of wireless LAN networks,
implementing a security infrastructure that monitors physical
access to the network can be difficult. Unlike a wired network
where a physical connection is required, anyone within range of a
wireless access point (AP) can conceivably send and receive frames
as well as listen for other frames being sent. This makes
eavesdropping and remote sniffing of wireless LAN frames very
easy.
[0034] WEP provides data confidentiality services by encrypting the
data sent between wireless nodes. WEP encryption for an 802.11
frame is indicated by setting a WEP flag in the MAC header of the
802.11 frame. WEP provides data integrity for random errors by
including an integrity check value (ICV) in the encrypted portion
of the wireless frame.
[0035] The following tables illustrates the two shared keys that
WEP defines:
TABLE-US-00001 TABLE 1 Key type Description Multicast/global key
Encryption key that helps to protect multicast and broadcast
traffic from a wireless AP to all of its connected wireless
clients. Unicast session key Encryption key that helps to protect
unicast traffic between a wireless client and a wireless AP and
multicast and broadcast traffic sent by a wireless client to the
wireless AP.
WEP encryption employs the RC4 symmetric stream cipher with 40-bit
and 104-bit encryption keys.
[0036] Wi-Fi Protected Access
[0037] WPA is a Wi-Fi standard designed to improve upon the
security features of WEP. Unlike WEP, 802.1x authentication is
required in WPA. With WPA, rekeying of both unicast and global
encryption keys is required. For the unicast encryption key, the
Temporal Key Integrity Protocol (TKIP) changes the key for every
frame, and the change is synchronized between the wireless client
and the wireless access point (AP). For the global encryption key,
WPA includes a facility for the wireless AP to advertise the
changed key to the connected wireless clients.
[0038] TKIP replaces WEP with an encryption algorithm that is
stronger than the WEP algorithm. TKIP also provides for
verification of the security configuration after the encryption
keys are determined; synchronized changing of the unicast
encryption key for each frame; and, determination of a unique
starting unicast encryption key for each pre-shared key
authentication.
[0039] WPA further employs a method known as "Michael" that
specifies an algorithm that calculates an 8-byte message integrity
code (MIC). The MIC is placed between the data portion of the IEEE
802.11 frame and the 4-byte integrity check value (ICV). The MIC
field is encrypted together with the frame data and the ICV.
[0040] WPA is an interim standard that will be replaced with the
IEEE's 802.11i standard upon its completion.
[0041] Wireless Provisioning Services (WPS) Supporting Networks
[0042] WPS allows Wi-Fi network providers and/or enterprises to
send provisioning and configuration information to a mobile client
as it connects to the Internet or a corporate network, providing
seamless and automatic provisioning and configuration of the client
with uniform sign-up experience. As a user logs onto a wireless
network, the network recognizes the user, automatically sets up the
session, and bills the user's account.
[0043] The security of a wireless session is improved because the
automatic authentication and encryption provided by WPS minimizes
the chances that a user's wireless session will be broken into by
rogue access points or hackers. With WPS, a network can request
substantially any type of information from the user, for example, a
user name, a coupon code, and/or demographic information.
[0044] Distinctions Between Example Wireless Network Types
[0045] Turning briefly to FIG. 2, a diagram 200 example wireless
network types in accordance with one or more embodiments.
[0046] Wireless networks encompassed by the original 802.11
specification 210 include encrypted 214 and not encrypted 216. The
802.1x specification further facilitated automatic distribution of
the WEP encryption key 222 and 802.1x authentication 224. The
introduction of WPS further provides for 802.1x authentication 224
to be sub-divided into network(s) that support WPS 242 and
network(s) that do not support WPS 244.
[0047] Alternatively, introduction of the WPA specification
provided for wireless network supporting the 802.11 specification
and further encompassing the WPA specification 230. These
network(s) are encrypted 234 and can be sub-divided into WPA 236
(e.g., 802.1x-enabled networks that support WPA) and WPA PSK 238.
With the introduction of WPS, the WPA node 236 can be further
sub-divided into network(s) that support WPS 252 and network(s)
that do not support WPS 254.
[0048] The Wireless Network Detection System 100
[0049] Returning to FIG. 1, the wireless network detection system
100 includes a connection component 110 and a detection component
120. The connection component 110 facilitates connection of a
client system 130 to at least one of a plurality of type of
wireless networks. The detection component 120 can iteratively
probe an available wireless network beacon 140 in connection with
identifying a type of the wireless network. For example, the system
100 can employ a probing technique to determine the network type of
a "new" network the first time the user tries to connect to it.
[0050] Additionally and/or alternatively, the system 100 can employ
an information element from the wireless network beacon 140 to
facilitate determination of the network type.
[0051] As discussed previously, conventionally, when a user comes
within range of a wireless network, the client computer is able to
discern two pieces of information about that network, without
connecting to it (e.g., from the wireless network beacon): (1) the
SSID of the network (e.g., essentially its name); and, (2) whether
or not the network encrypts data. If the network employs
encryption, an encryption key is required. The encryption key can
be manually entered by the user and/or via the 801.1.times.
protocol. Thus, for each of the network types, the information the
client computer requires from the user can be different.
[0052] However, with the information that the computer can retrieve
from the network beacon, the computer can only determine whether
the network is (a) unencrypted (type #1) or (b) encrypted (type #2
or #4) or, with the addition of the WPA information element,
encrypted using WPA-PSK (type #3) or encrypted using WPA (type
#5).
[0053] If it is unencrypted (e.g., type #1), then the user can
acknowledge that the network is insecure, and that they wish to use
it in spite of that information. However, if it is encrypted and
does not use WPA, then it is either of type #2 or #4. If it is type
#2, the user would need to enter a WEP key, and if it is type #4,
the user not need to enter a WEP key, but the client computer needs
to enable 802.1x authentication to complete the connection. Since
the client computer cannot tell whether the network is #2 or #4, it
essentially has to ask the user. In the vast majority of cases, the
user is in no position (from a technical knowledge perspective) to
answer such a question. The introduction of WPS network(s) has made
the situation even more complicated (e.g., three different types of
encrypted networks).
[0054] The wireless network detection system 100 efficiently and
safely determines which of a plurality of network types the user is
attempting to connect to, in order to present the user with
appropriate user interface (UI). As noted previously, for each of
the network types, the information the client computer needs from
the user can be different. Thus, the system 100 can provide a way
to distinguish whether (1) a manually-entered WEP key or (2) 802.1x
authentication is required by the wireless network without
significant user input.
[0055] In one example, the system 100 employs an information
element (IE) from the wireless network beacon 140 to facilitate
determination of the network type. The general concept of an IE is
part of the 802.11 standard. In accordance with one or more
embodiments, a specific IE, for example, two bits, can be used to
provide information to distinguish between the types of network
(e.g., three). The following table illustrated the structure and
layout of an example IE:
TABLE-US-00002 TABLE 2 Size Name Value (octets) Description Element
ID 0xDD 1 Length 11 1 OUI 0x00:50:f2 3 OUI Type 5 1 WPS supported
True/False 1 Indicates whether the network supports wireless
provisioning services 802.1X required True/False 1 For WEP (not
WPA) networks, indicates whether 802.1X is required
[0056] In this example, the wireless network beacon 140 provides
the IE to the detection component 120. Based, at least in part,
upon the IE, the detection component 120 identifies the type of
wireless network.
[0057] In another example, the system 100 employs a probing
technique to determine the encryption type of a network, for
example, performed the first time the user tries to connect to it.
For example, the detection component 120 can first attempt to
connect to the wireless network as if it were a WPS network. WPS
networks are a subset of 802.1x networks (e.g., type #4 or type #5)
and may or may not support WPA. By waiting for certain kinds of
failure(s) in the authentication sequence, the detection component
120 can determine if the network is of type #2 (e.g., manually
entered WEP key). For example, the probing can mitigate impact upon
the user by recognizing a common type of network (e.g., manually
entered WEP key).
[0058] If the failures are not observed, the detection component
120 can wait a longer period of time (e.g., up to thirty seconds)
for a particular piece of the authentication sequence (e.g.,
Protected extensible authentication protocol-type length value
(PEAP-TLV)) that identifies a WPS network. In the absence of this
piece of the sequence, the detection component 120 can identify the
wireless network as type #4 or type #5 to the connection component
110. If the particular piece of the authentication sequence is
detected by the detection component 120, then the detection
component 120 can identify the network as a WPS supporting network
to the connection component 110.
[0059] Accordingly, the user is not asked to determine the network
type. This can lead, for example, to user(s) who are more
successful in their use of wireless networks and further reduce
user frustration with wireless network(s).
[0060] It is to be appreciated that the wireless network detection
system 100, the connection component 110, the detection component
120, the client system 130 and/or the wireless network beacon 140
can be computer components as that term is defined herein.
[0061] Turning briefly to FIGS. 3-5, methodologies that may be
implemented in accordance with one or more embodiments are
illustrated. While, for purposes of simplicity of explanation, the
methodologies are shown and described as a series of blocks, it is
to be understood and appreciated that embodiments are not limited
by the order of the blocks, as some blocks may, in accordance with
one or more embodiments, occur in different orders and/or
concurrently with other blocks from that shown and described
herein. Moreover, not all illustrated blocks may be required to
implement the methodologies in accordance with one or more
embodiments.
[0062] Embodiments may be described in the general context of
computer-executable instructions, such as program modules, executed
by one or more components. Generally, program modules include
routines, programs, objects, data structures, etc. that perform
particular tasks or implement particular abstract data types.
Typically the functionality of the program modules may be combined
or distributed as desired in various embodiments.
[0063] Referring to FIG. 3, a method facilitating wireless network
detection 300 in accordance with an aspect of one or more
embodiments is illustrated. At 310, connection to a wireless
network as a WPS network is attempted. At 320, a determination is
made as to whether the attempt was successful. If the determination
at 320 is NO, at 330, the wireless network is identified as
required a WEP key, and, no further processing occurs.
[0064] If the determination at 320 is YES, at 340, up to a
threshold period of time (e.g., 30 seconds) is waited for a receipt
of a particular piece of authentication information that identifies
a WPS network (e.g., PEAP-TLV sequence). At 350, a determination is
made as to whether the particular piece of authentication
information has been received. If the determination at 350 is NO,
at 360, the network is identified as type #4 or type #5, and, no
further processing occurs. If the determination at 350 is YES, at
370, the network is identified as WPS-supporting, and, no further
processing occurs.
[0065] Next, referring to FIGS. 4 and 5, a method facilitating
wireless network detection 400 in accordance with an aspect of one
or more embodiments is illustrated. At 404, the connection process
is begun. At 408, a determination is made as to whether the
wireless network is encrypted (e.g., based, at least in part, upon
information received from the wireless network beacon). If the
determination at 408 is NO, at 412, the network is identified as
not encrypted. At 416, a user can be prompted for confirmation to
connect to an insecure network, and, no further processing
occurs.
[0066] If the determination at 408 is YES, at 420, a determination
is made as to whether the network is WPA (e.g., based, at least, in
part, upon information received from the wireless network beacon).
If the determination at 420 is YES, at 422, at determination is
made as to whether the network is WPA PSK (e.g., based, at least in
part, upon information received from the wireless network beacon).
If the determination at 422 is YES, at 424, the network is
identified as WPA PSK. At 428, a user can be prompted to enter a
WPA pre-shared key, and, no further processing occurs. If the
determination at 422 is NO, processing continues at 432.
[0067] If the determination at 420 is NO, at 432, a determination
is made as to whether the network supports 802.1x. For example, as
discussed previously, the determination can be made by employing a
probing technique and/or an information element received from the
wireless network beacon. If the determination at 432 is NO, at 436,
the network is identified as a manual WEP type. At 440, a user can
be prompted to enter a WEP key, and, no further processing
occurs.
[0068] If the determination at 432 is YES, at 444, a determination
is made as to whether the network supports WPS. Again, the
determination can be made by employing a probing technique and/or
an information element received from the wireless network beacon.
If the determination at 444 is YES, at 448, the network is
identified as WPS-supporting. At 452, WPS information can be loaded
and the connection continued, and, no further processing
occurs.
[0069] If the determination at 444 is NO, at 456, the network is
identified as an 802.1x network. At 460, connection to the wireless
network can be continued using a default 802.1x authentication
type, and, no further processing Occurs.
[0070] In order to provide additional context for various aspects
of one or more embodiments, FIG. 6 and the following discussion are
intended to provide a brief, general description of a suitable
operating environment 610 in which various aspects of one or more
embodiments may be implemented. While embodiments are described in
the general context of computer-executable instructions, such as
program modules, executed by one or more computers or other
devices, those skilled in the art will recognize that embodiments
can also be implemented in combination with other program modules
and/or as a combination of hardware and software. Generally,
however, program modules include routines, programs, objects,
components, data structures, etc. that perform particular tasks or
implement particular data types. The operating environment 610 is
only one example of a suitable operating environment and is not
intended to suggest any limitation as to the scope of use or
functionality of one or more embodiments. Other well known computer
systems, environments, and/or configurations that may be suitable
for use with one or more embodiments include but are not limited
to, personal computers, hand-held or laptop devices, multiprocessor
systems, microprocessor-based systems, programmable consumer
electronics, network PCs, minicomputers, mainframe computers,
distributed computing environments that include the above systems
or devices, and the like.
[0071] With reference to FIG. 6, an example environment 610 for
implementing various aspects of one or more embodiments includes a
computer 612. The computer 612 includes a processing unit 614, a
system memory 616, and a system bus 618. The system bus 618 couples
system components including, but not limited to, the system memory
616 to the processing unit 614. The processing unit 614 can be any
of various available processors. Dual microprocessors and other
multiprocessor architectures also can be employed as the processing
unit 614.
[0072] The system bus 618 can be any of several types of bus
structure(s) including the memory bus or memory controller, a
peripheral bus or external bus, and/or a local bus using any
variety of available bus architectures including, but not limited
to, an 8-bit bus, Industrial Standard Architecture (ISA),
Micro-Channel Architecture (MSA), Extended ISA (EISA), Intelligent
Drive Electronics (IDE), VESA Local Bus (VLB), Peripheral Component
Interconnect (PCI), Universal Serial Bus (USB), Advanced Graphics
Port (AGP), Personal Computer Memory Card International Association
bus (PCMCIA), and Small Computer Systems Interface (SCSI).
[0073] The system memory 616 includes volatile memory 620 and
nonvolatile memory 622. The basic input/output system (BIOS),
containing the basic routines to transfer information between
elements within the computer 612, such as during start-up, is
stored in nonvolatile memory 622. By way of illustration, and not
limitation, nonvolatile memory 622 can include read only memory
(ROM), programmable ROM (PROM), electrically programmable ROM
(EPROM), electrically erasable ROM (EEPROM), or flash memory.
Volatile memory 620 includes random access memory (RAM), which acts
as external cache memory. By way of illustration and not
limitation, RAM is available in many forms such as synchronous RAM
(SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data
rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM
(SLDRAM), and direct Rambus RAM (DRRAM).
[0074] Computer 612 also includes removable/nonremovable,
volatile/nonvolatile computer storage media. FIG. 6 illustrates,
for example a disk storage 624. Disk storage 624 includes, but is
not limited to, devices like a magnetic disk drive, floppy disk
drive, tape drive, Jaz drive, Zip drive, LS-100 drive, flash memory
card, or memory stick. In addition, disk storage 624 can include
storage media separately or in combination with other storage media
including, but not limited to, an optical disk drive such as a
compact disk ROM device (CD-ROM), CD recordable drive (CD-R Drive),
CD rewritable drive (CD-RW Drive) or a digital versatile disk ROM
drive (DVD-ROM). To facilitate connection of the disk storage
devices 624 to the system bus 618, a removable or non-removable
interface is typically used such as interface 626. As recited
herein, storage media does not include signals per se.
[0075] It is to be appreciated that FIG. 6 describes software that
acts as an intermediary between users and the basic computer
resources described in suitable operating environment 610. Such
software includes an operating system 628. Operating system 628,
which can be stored on disk storage 624, acts to control and
allocate resources of the computer system 612. System applications
630 take advantage of the management of resources by operating
system 628 through program modules 632 and program data 634 stored
either in system memory 616 or on disk storage 624. It is to be
appreciated that one or more embodiments can be implemented with
various operating systems or combinations of operating systems.
[0076] A user enters commands or information into the computer 612
through input device(s) 636. Input devices 636 include, but are not
limited to, a pointing device such as a mouse, trackball, stylus,
touch pad, keyboard, microphone, joystick, game pad, satellite
dish, scanner, TV tuner card, digital camera, digital video camera,
web camera, and the like. These and other input devices connect to
the processing unit 614 through the system bus 618 via interface
port(s) 638. Interface port(s) 638 include, for example, a serial
port, a parallel port, a game port, and a universal serial bus
(USB). Output device(s) 640 use some of the same type of ports as
input device(s) 636. Thus, for example, a USB port may be used to
provide input to computer 612, and to output information from
computer 612 to an output device 640. Output adapter 642 is
provided to illustrate that there are some output devices 640 like
monitors, speakers, and printers among other output devices 640
that require special adapters. The output adapters 642 include, by
way of illustration and not limitation, video and sound cards that
provide a means of connection between the output device 640 and the
system bus 618. It should be noted that other devices and/or
systems of devices provide both input and output capabilities such
as remote computer(s) 644.
[0077] Computer 612 can operate in a networked environment using
logical connections to one or more remote computers, such as remote
computer(s) 644. The remote computer(s) 644 can be a personal
computer, a server, a router, a network PC, a workstation, a
microprocessor based appliance, a peer device or other common
network node and the like, and typically includes many or all of
the elements described relative to computer 612. For purposes of
brevity, only a memory storage device 646 is illustrated with
remote computer(s) 644. Remote computer(s) 644 is logically
connected to computer 612 through a network interface 648 and then
physically connected via communication connection 650. Network
interface 648 encompasses communication networks such as local-area
networks (LAN) and wide-area networks (WAN). LAN technologies
include Fiber Distributed Data Interface (FDDI), Copper Distributed
Data Interface (CDDI), Ethernet/IEEE 802.3, Token Ring/IEEE 802.5
and the like. WAN technologies include, but are not limited to,
point-to-point links, circuit switching networks like Integrated
Services Digital Networks (ISDN) and variations thereon, packet
switching networks, and Digital Subscriber Lines (DSL).
[0078] Communication connection(s) 650 refers to the
hardware/software employed to connect the network interface 648 to
the bus 618. While communication connection 650 is shown for
illustrative clarity inside computer 612, it can also be external
to computer 612. The hardware/software necessary for connection to
the network interface 648 includes, for example purposes only,
internal and external technologies such as, modems including
regular telephone grade modems, cable modems and DSL modems, ISDN
adapters, and Ethernet cards.
[0079] What has been described above includes examples of one or
more embodiments. It is, of course, not possible to describe every
conceivable combination of components or methodologies for purposes
of describing one or more embodiments, but one of ordinary skill in
the art may recognize that many further combinations and
permutations of the embodiments are possible. Accordingly,
embodiments are intended to embrace all such alterations,
modifications and variations that fall within the spirit and scope
of the appended claims Furthermore, to the extent that the term
"includes" is used in either the detailed description or the
claims, such term is intended to be inclusive in a manner similar
to the term "comprising" as "comprising" is interpreted when
employed as a transitional word in a claim.
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