U.S. patent application number 12/474020 was filed with the patent office on 2009-11-26 for method and apparatus for controlling wireless network access privileges based on wireless client location.
This patent application is currently assigned to Trapeze Networks, Inc.. Invention is credited to Matthew K. Gray, Coleman P. Parker, Jeffrey J. Peden, II.
Application Number | 20090293106 12/474020 |
Document ID | / |
Family ID | 37003370 |
Filed Date | 2009-11-26 |
United States Patent
Application |
20090293106 |
Kind Code |
A1 |
Gray; Matthew K. ; et
al. |
November 26, 2009 |
METHOD AND APPARATUS FOR CONTROLLING WIRELESS NETWORK ACCESS
PRIVILEGES BASED ON WIRELESS CLIENT LOCATION
Abstract
An access point through which a wireless device attaches to a
wireless network determines the access privileges that will be
accorded to the device based on a criteria set, such as the ID and
physical location of the device requesting network access, the
access point through which the device is connected to the network
and user credentials. The location of the device is determined by a
location determination system using the signal strength of the
device signal. The location information and ID information is
provided to an access server that uses the criteria set to retrieve
access privileges from a privilege database. The retrieved access
privileges are then applied to the wireless device by means of the
access point and other devices in the wireless network.
Inventors: |
Gray; Matthew K.;
(Somerville, MA) ; Peden, II; Jeffrey J.;
(Burlington, MA) ; Parker; Coleman P.; (Watertown,
MA) |
Correspondence
Address: |
PERKINS COIE LLP
P.O. BOX 1208
SEATTLE
WA
98111-1208
US
|
Assignee: |
Trapeze Networks, Inc.
Pleasanton
CA
|
Family ID: |
37003370 |
Appl. No.: |
12/474020 |
Filed: |
May 28, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11094987 |
Mar 31, 2005 |
7551574 |
|
|
12474020 |
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Current U.S.
Class: |
726/4 |
Current CPC
Class: |
H04L 63/0876 20130101;
H04L 63/0254 20130101; H04W 12/08 20130101; H04W 12/79 20210101;
H04L 63/102 20130101; H04L 63/107 20130101; H04W 12/06 20130101;
H04L 63/108 20130101; H04L 12/4641 20130101 |
Class at
Publication: |
726/4 |
International
Class: |
G06F 17/30 20060101
G06F017/30 |
Claims
1. A method for controlling access privileges in a wireless network
based on the location of a wireless client that is connected to the
network via radio-frequency signals sent between the wireless
client and an access point, the method comprising: (a) computing
the location of the wireless client based on measured properties of
the radio frequency signals; (b) receiving information that
identifies the wireless client; (c) generating a set of access
privileges based on the location and the identifying information of
the wireless client; and (d) applying the access privileges to the
wireless client.
2. The method of claim 1 wherein step (a) comprises computing the
location of the wireless client using an RF fingerprinting
method.
3. The method of claim 1 wherein step (b) comprises receiving from
the access point a device ID of the wireless client.
4. The method of claim 3 wherein the device ID is a device MAC
address.
5. The method of claim 3 wherein step (b) comprises receiving from
the access point an access point ID of the access point.
6. The method of claim 1 wherein step (c) comprises retrieving the
set of access privileges from a privilege database using the
location and the identifying information of the wireless
client.
7. The method of claim 1 wherein the access point interacts with a
RADIUS server to obtain access to the network and wherein step (d)
comprises sending the access privileges to the RADIUS server and
using the radius server to cause the access point to apply the
privileges.
8. The method of claim 1 wherein step (d) comprises assigning the
wireless client to a virtual LAN, identifying each data packet sent
from the wireless client with a tag specifying that the data packet
is part of the virtual LAN and using devices that respond to the
tag to apply the access privileges.
9. The method of claim 8 wherein step (d) further comprises
changing the access privileges assigned to the wireless client by
changing the virtual LAN to which the wireless client is
assigned.
10. The method of claim 8 wherein step (d) further comprises
changing the access privileges assigned to the wireless client by
changing devices that respond to the tag to apply different access
privileges to the wireless client.
11. The method of claim 1 wherein step (d) comprises using stateful
packet filtering to apply the privileges.
12. The method of claim 1 wherein step (c) is performed by an
access server connected to the wireless network and wherein the
access point recurrently polls the access server to cause step (c)
to be recurrently performed.
13. The method of claim 1 wherein step (c) is recurrently performed
and the set of access privileges is recurrently sent to the access
point.
14. The method of claim 1 wherein step (d) comprises applying the
access privileges to the wireless client for a predetermined period
of time.
15. The method of claim 14 wherein step (d) comprises performing an
additional action after the predetermined period of time has
expired.
16. The method of claim 1 wherein step (d) comprises applying the
access privileges to the wireless client based on the time of
day.
17. Apparatus for controlling access privileges in a wireless
network based on the location of a wireless client that is
connected to the network via radio-frequency signals sent between
the wireless client and an access point, the apparatus comprising:
a location system that computes the location of the wireless client
based on measured properties of the radio frequency signals; an
access server that receives information that identifies the
wireless client; a policy server that generates a set of access
privileges based on the location and the identifying information of
the wireless client; and a mechanism that applies the access
privileges to the wireless client.
18. The apparatus of claim 17 wherein the location system comprises
means for computing the location of the wireless client using an RF
fingerprinting method.
19. The apparatus of claim 17 wherein the access server comprises
means for receiving from the access point a device ID of the
wireless client.
20. The apparatus of claim 19 wherein the device ID is a device MAC
address.
21. The apparatus of claim 19 wherein the access server comprises
means for receiving from the access point an access point ID of the
access point.
22. The apparatus of claim 17 wherein the policy server comprises
means for retrieving the set of access privileges from a privilege
database using the location and the identifying information of the
wireless client.
23. The apparatus of claim 17 wherein the access point interacts
with a RADIUS server to obtain access to the network and wherein
the mechanism that applies the access privileges to the wireless
client comprises means for sending the access privileges to the
RADIUS server and means for using the radius server to cause the
access point to apply the privileges.
24. The apparatus of claim 17 wherein the mechanism that applies
the access privileges to the wireless client comprises: means for
assigning the wireless client to a virtual LAN; means for
identifying each data packet sent from the wireless client with a
tag specifying that the data packet is part of the virtual LAN; and
means for using devices that respond to the tag to apply the access
privileges.
25. The apparatus of claim 24 wherein the mechanism that applies
the access privileges to the wireless client further comprises
means for changing the access privileges assigned to the wireless
client by changing the virtual LAN to which the wireless client is
assigned.
26. The apparatus of claim 24 wherein the mechanism that applies
the access privileges to the wireless client further comprises
means for changing the access privileges assigned to the wireless
client by changing devices that respond to the tag to apply
different access privileges to the wireless client.
27. The apparatus of claim 17 wherein the mechanism that applies
the access privileges to the wireless client comprises means for
using stateful packet filtering to apply the privileges.
28. The apparatus of claim 17 wherein the access point recurrently
polls the access server to recurrently cause the policy server to
generate a set of access privileges based on the location and the
identifying information of the wireless client.
29. The apparatus of claim 17 wherein the policy server recurrently
generates a set of access privileges based on the location and the
identifying information of the wireless client and the generated
set of access privileges is recurrently sent to the access
point.
30. The apparatus of claim 17 wherein the mechanism that applies
the access privileges to the wireless client comprises means for
applying the access privileges to the wireless client for a
predetermined period of time.
31. The apparatus of claim 30 wherein the mechanism that applies
the access privileges to the wireless client comprises means for
performing an additional action after the predetermined period of
time has expired.
32. The apparatus of claim 17 wherein the mechanism that applies
the access privileges to the wireless client comprises means for
applying the access privileges based on the time of day.
33. Apparatus for controlling access privileges in a wireless
network based on the location of a wireless client that is
connected to the network via radio-frequency signals sent between
the wireless client and an access point, the apparatus comprising:
means for computing the location of the wireless client based on
measured properties of the radio frequency signals; means for
receiving information that identifies the wireless client; means
for generating a set of access privileges based on the location and
the identifying information of the wireless client; and means for
applying the access privileges to the wireless client.
34. The apparatus of claim 33 wherein the means for computing the
location of the wireless client comprises means for computing the
location of the wireless client using an RF fingerprinting
method.
35. A computer program product for controlling access privileges in
a wireless network based on the location of a wireless client that
is connected to the network via radio-frequency signals sent
between the wireless client and an access point, the computer
program product comprising a computer usable medium having computer
readable program code thereon, including: program code for
computing the location of the wireless client based on measured
properties of the radio frequency signals; program code for
receiving information that identifies the wireless client; program
code for generating a set of access privileges based on the
location and the identifying information of the wireless client;
and program code for applying the access privileges to the wireless
client.
36. The computer program product of claim 35 wherein the program
code for computing the location of the wireless client comprises
program code for computing the location of the wireless client
using an RF fingerprinting method.
Description
FIELD OF THE INVENTION
[0001] This invention relates to wireless networks and, more
particularly, to controlling access privileges of wireless clients
that either attempt to access the network or are connected to the
network, but change their status.
BACKGROUND OF THE INVENTION
[0002] Wireless networks that link together multiple computers are
commonplace and the technology for implementing such networks is
rapidly growing. The common names for such networking technology
are "wireless networking", "WiFi" or "802.11 networking." The big
advantage of wireless networking is simplicity, because it allows
computers to be connected anywhere in a home or office without the
need for physical wires, thereby allowing the computers to be
mobile. The computers, called "wireless clients", connect to the
network using broadcast radio signals which can travel up to
distances of approximately 100 feet.
[0003] Wireless networks are generally governed by one of several
standards promulgated by the Institute of Electrical and
Electronics Engineers (IEEE). The basic standard is denoted as the
802.11 standard and covers wireless networks. The standard has
several different versions labeled by a, b and g notations. The
different standard versions differ in several respects, including
the broadcast signal frequency, transmission speed and data coding
techniques. For example, the first wireless networking systems to
reach the marketplace were constructed according to the 802.11b
standard. Equipment that conforms to the 802.11b standard transmits
at 2.4 GHz, can handle data transmission speeds up to 11 megabits
per second and uses a data coding technique called "complementary
code keying". The 802.11a standard next appeared. Equipment
conforming to this standard operates at 5 GHz, can handle up to 54
megabits per second and uses a data coding technique called
"orthogonal frequency-division multiplexing" (OFDM). The 802.11g
standard has characteristics of both the 802.11a and 802.11b
standards in that conforming equipment operates at 2.4 Ghz, but has
data transmission speeds of 54 megabits per second and uses OFDM
encoding.
[0004] Wireless communications are usually designed to take place
in a localized area quite often via a local communications network.
Such a localized area may be a building, an area within a building,
an area comprising several buildings, outdoor areas, or a
combination of indoor and outdoor areas. However, due to the
broadcast nature of the radio-frequency signal, persons outside of
the localized area can often receive the signal and, thus,
communicate with the network. In many environments, information on
the network is confidential and the ability of unauthorized persons
to attach to the network is a serious problem.
[0005] A common technique for enhancing the security of a wireless
network is to encode the information broadcast via the
radio-frequency signals with a WEP key. WEP stands for "Wired
Equivalent Privacy", and is an encryption standard that is part of
the 802.11 standard. Another technique is to track the physical
location of the mobile equipment and disconnect it from the network
if the equipment strays outside of a predetermined localized
area.
[0006] The communication between mobile wireless devices and the
local area network (LAN) is often performed using devices, such as
"access points" (APs) that are attached to the LAN. The APs are
communication ports for wireless devices, which broadcast the
radio-frequency signals to, and receive the radio-frequency signals
from, the wireless clients. The APs pass messages received from the
wireless device across the LAN to other servers, computers,
applications, subsystems or systems, as appropriate. Typically, the
APs are coupled to one or more network servers, which manage the
message traffic flow. Application servers may be coupled to or
accessed via the network servers, to provide data or typical
application functionality to the wireless device.
[0007] Detection and location within a defined local area is often
performed using a LAN to which a set of sensors is attached. In
order to use such a local area network to determine the physical
location of a wireless client, the local area network is equipped
with a plurality of radio-frequency signal sensors, which may be
incorporated into the access points or may be separate from the
access points. Using a technique called "RF fingerprinting" a
digital definition of the physical localized area is first
developed and then a statistical signal strength model is developed
to provide a context within which the detection and tracking will
occur. Then the actual radio-frequency signal strength as measured
at the sensors is compared to the model to calculate the physical
location of each device.
[0008] The digital definition of the localized area is comprised of
a set of defined regions, areas or locations (collectively referred
to as "locales") taking into account various obstructions. Once the
digital form of the localized area is formed, the locales are
defined and the statistical signal strength model is then
defined.
[0009] With the digital form of the physical space defined, the
signal strength model can be determined. The signal strength model
defines, for each access point within the localized area, a pattern
of signal strength reception that is anticipated from a mobile
device transmitting within the area, taking into account the
obstructions and placement of the access points. The signal
strength model can be created by actually installing sensors in the
physical space and then measuring the strength of signals received
at the sensors as a transmitting wireless client moves through the
area. Alternatively, simulated access points and simulated wireless
client readings can be used to generate the signals strength
model.
[0010] After the signal strength model is determined, the location
of a wireless client can be determined by collecting actual signal
strength data from the device as it moves about or resides in the
localized area and comparing the actual data against values
predicted by the signal strength model. The RF fingerprinting
process is described in more detail in U.S. Pat. No. 6,674,403, the
contents of which are hereby incorporated in their entirety by
reference.
[0011] Alternatively, other location techniques could be used. For
example, some known location techniques use the time of arrival of
signals or differences between the time of arrival of signals from
the wireless device at the APs to calculate the location of the
wireless device. For example, such systems are described in U.S.
Pat. Nos. 6,801,782 and 6,756,940.
[0012] Once a wireless client has been located, access is usually
denied if the unit is outside the localized area. This provides
security and prevents unauthorized users from attaching or staying
attached to the network, but is not very flexible because the
system cannot differentiate between authorized users who are
properly attached to the network.
SUMMARY OF THE INVENTION
[0013] In accordance with the principles of the invention, the
access point through which a device attaches to the network
determines the access privileges that will be accorded to the
device based on a criteria set, such as the ID and physical
location of the device requesting network access, the access point
through which the device is connected to the network and user
credentials. The criteria set is used to determine network access
privileges that can include access (or lack thereof to different
portions of the network, access to particular local hosts, access
to the Internet, access to particular hosts on the Internet, access
to particular services on the Internet (filtered either by port or
by stateful protocol analysis), restrictions on bandwidth
consumption, flagging of traffic with particular quality of service
benefits or restrictions, or any number of other network
configuration parameters.
[0014] When a device changes any of the criteria in the criteria
set, the network access privileges dynamically change in an
appropriate manner. Similarly, if the network access privileges for
that criteria set change, then the network access privileges for a
device with that criteria set would change to conform. In some
cases, when enough information has not been collected to accurately
determine the location of a device, the device would be assigned
default network access privileges.
[0015] In one embodiment, an access point contacts an access server
on the network and requests network access privileges that should
be provided to the device requesting access. In another embodiment,
the access server publishes the network access privilege
information to all access points, either in response to a poll by
an access point or asynchronously.
[0016] In another embodiment, virtual local area networks (VLANs)
are established on the network and each device is assigned to a
particular VLAN. Network access privileges can then be assigned to
a particular VLAN.
[0017] In still another embodiment, a VLAN is created by tagging
each data packet or frame with an ID code associated with a
particular VLAN. Special access points are used that detect the tag
and use the VLAN ID code to determine the network access privileges
accorded to the VLAN and, thus, to the user.
[0018] In yet another embodiment, network access restrictions can
be applied by another device in the data path, such as a switch,
router or gateway. In addition, restrictions could also be applied
by a stateful packet filter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The above and further advantages of the invention may be
better understood by referring to the following description in
conjunction with the accompanying drawings in which:
[0020] FIG. 1 is a block schematic diagram showing typical
components in a wireless network.
[0021] FIG. 2 is a more detailed block schematic diagram of a
server in the system of FIG. 1 incorporating a location system and
an access server.
[0022] FIG. 3 is a flowchart showing the steps in an illustrative
process for applying network access privileges to wireless clients
in accordance with the principles of the invention.
DETAILED DESCRIPTION
[0023] FIG. 1 is a block schematic diagram of a typical wireless
network 100. Two wireless clients, 102 and 104, are shown. The
wireless clients 102 and 104 are linked to the network 100 by means
of access points of which two access points 108 and 112 are
illustrated in the figure. Those skilled in the art would
understand that at least one access point is required, but typical
networks would have many access points.
[0024] The access points 108 and 112 are connected to a network 116
which can be a LAN, such as an Ethernet network, or another type of
network. The network 116 may also have other devices, such as
servers 118 and 120 connected to it. Network 116 may further be
connected to another network, such as a WAN or the Internet via a
router 114.
[0025] One or more signal sensors may also be connected to the
network 116, of which two sensors, 106 and 110, are shown. These
sensors measure the signal strength of the RF signal generated by
the wireless clients 102 and 104 and are used by a conventional
location tracking system, for example, an RF fingerprinting system
as described above. As known in the art, the sensors 106 and 110
may also be integrated into the access points 108 and 112. The
location tracking system typically operates on one of the servers,
such as server 118. In accordance with the principles of the
invention, the server 118 may also incorporate an access control
system.
[0026] In one embodiment, the access control system operates when a
wireless client, such as client 102 connects to a wireless access
point, such as access point 108. Access point 108 then contacts the
access control server 118 and requests information on the network
access privileges that should be provided to the client 102. The
server then accesses a database to retrieve the privileges assigned
to the client based on information identifying the client, the
device location, the access point to which the client is connected
and other user authentication credentials. For example in one
embodiment, the wireless client device can be identified by using
the device Media Access Control (MAC) address as a client device
ID. Similarly, the access point is identified by its network IP
address. The additional information can include user credentials.
This information is sent to the access control server with the
request. Alternatively, information that identifies the wireless
client may be sent directly from the wireless client, via the
access point, to the access control server.
[0027] A more detailed view of server 118 incorporating the access
system is shown in FIG. 2 and the process performed by the system
is shown in FIG. 3. The process begins in step 300 and proceeds to
step 302 where a wireless client requests access to the network
from a wireless access point. The wireless access point, in turn,
requests access to the network from the access system and
specifically from an access server 210 over the network 208 as
shown in step 304.
[0028] In one embodiment, the access server 210 is a RADIUS (Remote
Authentication Dial In User Services) server. A RADIUS server
performs access control services in accordance with the well-known
RADIUS access control protocol that defines a request/response
process. The RADIUS protocol is well-known and is defined by the
Internet Engineering Task Force (IETF) in Request for Comment (RFC)
2865 and expanded in additional documents published by the IETF. In
this embodiment, the access server 210 acts as a RADIUS security
server. When an access point makes a request on behalf of a
wireless client for network access, the access server 210 also
receives information identifying the wireless client and access
point from the access point. Using this information, the access
server 210 consults a policy server 204 as set forth in step 306,
which generates network access privileges assigned to that wireless
client. In accordance with the RADIUS protocol, the access server
210 then returns a permit access or deny access response to the
access point. If a permit access response is returned, the access
server uses the privilege information returned by the policy server
to specify additional restrictions or privileges to be applied to
the wireless client. Restrictions on access to a particular device
are implemented using the media access control (MAC) address of
that device. Restrictions based on the access point use the access
point ID code. User credential restrictions are based on user
credentials specified in a set of standards known as IEEE 802.11i
standards which build upon an IEEE 802.1X standard.
[0029] As noted above, the access server 210 consults a policy
server 204 that is also running in the access server 118. When the
policy server 204 receives a request from the access server 210 for
network access privilege information for a particular wireless
client, as set forth in step 308, it requests location information
from a location system 200 running in server 118 as indicated
schematically by arrow 202 using the client device ID received from
the access point, via the access server 210, to identify the
client. In particular, as previously mentioned, location system 200
uses information collected from signal strength sensors to
calculate the location of wireless clients in the system.
[0030] The location informed returned by the location system 200
may take one of several forms. In one form, the location
information is a label which may have hierarchical, adjacency and
geometric relationships with other labeled locations. For example,
two very broad locations called "zones" may be used called the
"inside" zone and the "outside" zone. The "Inside" zone may be
composed of sub-zones, such as "engineering", "executive" and
"sales". The "engineering" sub-zone and the "sales" sub-zone may be
adjacent, but the "engineering" sub-zone may not be adjacent to the
"executive" sub-zone. Further, each location may have a specified
geometry associated with it in one or more coordinate frames
(called "views") corresponding to different maps or visualizations
of a space. The location information may also take the form of a
set of coordinates, xyz at a minimum and theoretically also
containing other degrees of freedom. Location information may
further consist of multiple labels or coordinates and associated
confidences. For example "inside": 90%, "outside": 10%,
"engineering": 70% and "sales": 30%. In this arrangement, due to
the hierarchical nature of the locations, the confidences only sum
to 100% at the same level in the hierarchy. The location
information is returned from the location system 200 to the access
server 204 as indicated schematically by arrow 212.
[0031] Next, in step 310, using the client device ID, the device
location, the access point to which the client is connected and the
other user authentication credentials provided by the access point,
the policy server 204 accesses the privilege database 206 and
retrieves the privilege set associated with the combination of
information provided by the access point. For example, the location
information may be used to control access by a particular
configured mapping, such as a client device located in the
"outside" zone is not granted access; a client device located in
the "inside" zone is granted "standard access" and a client device
located in the "engineering" sub-zone is granted "privileged
access."
[0032] Alternatively, the location information may be applied such
that rights are dynamically granted and revoked. For example, a
client device may be initially fully restricted and with no
privileges and thus be unable to access any services on the
network. If the same device moves to the "inside" zone, it is
granted rights A, B and C. Later, if that device moves to the
"sales" sub-zone, it is granted right D and right A is revoked.
Still later if the device moves to the "engineering" sub-zone, it
is granted grant right E and right B is revoked. Alternatively, if
that device is located in the "executive" sub-zone, it is granted
rights D, F and G and rights A and C are revoked.
[0033] Further, policies may be applied based on "second order"
information about the location. For example, a client device may be
granted network access only if it is in the same location as a
device in previously defined privileged group or a device may be
granted access if it has been in a particular location in the past
twenty-four hours. Finally, in each of these cases the applied
policy could be determined by asking an external system
[0034] In addition to the combination of the client device ID,
device location, access point ID and user authentication
credentials, a wide range of other qualifications could apply,
including the time of day, any previously-visited locations, the
presence of other particular users in the same location, the
quantity of users in the same location, the presence or quantity of
users in some other fixed or related location, the data rate of
communication, the presence or absence of other users on the same
access point, the relative location of the user and the access
point and permutations of the aforementioned criteria. Further,
privileges and restrictions may be applied for a period of time
during which the privileges and restrictions are valid. For
example, a given set of privileges and restrictions may be applied
for the next ten minutes. After the period of time has expired, the
policy server can specify an additional action that can be
performed. For example, the policy server may specify that, after
the period of time has expired, the network connection will be
terminated, or the wireless client will be required to request an
additional time period for access.
[0035] The privilege set retrieved from the database 206 specifies
various privileges or restrictions that are applied to the wireless
client. These privileges and restriction can include granting, or
denial, of access to (1) different portions of the network 208, (2)
particular hosts on the network 208, (3) the Internet, (4)
particular hosts on the Internet and (5) particular services on the
Internet (filtered either by port or by stateful protocol
analysis). Other restrictions can include restrictions on bandwidth
consumption. Other operations can also be performed, such as
flagging of traffic with particular quality of service restrictions
or benefits or any number of other network configuration
parameters. Privileges and restrictions are typically applied by a
component in the data path between the wireless client device and
the network to which it is connected. This component will typically
be an access point, a switch or a router. The inline component will
apply the privileges and restrictions by routing, dropping,
redirecting, modifying or responding to each packet based on the
privilege set.
[0036] In the aforementioned embodiment using RADIUS servers, once
the policy server 204 obtains the privilege set and restrictions
from the privilege database 206, it returns the access information
to the access server 210 in step 312. Then, in step 314, the access
server 210 applies the restrictions to the wireless client
identified by the client device ID. The process then finishes in
step 314.
[0037] In another embodiment, access restrictions and privileges
are applied across the network by using the RADIUS access server
210 to assign each client device to a virtual local network (VLAN)
that is established using VLAN tagging. More specifically, a
particular restriction and privilege set is associated with a VLAN
and inline components mentioned above are programmed to provide
privileges and restrictions to all devices on that VLAN. With this
arrangement, a particular restriction and privilege set is applied
to a client by assigning that client to a VLAN that has been
programmed to implement those privileges and restrictions.
[0038] A VLAN can be established by tagging each data packet
generated by a device assigned to that VLAN with information that
identifies the VLAN. VLAN tagging can be carried out in compliance
with an IEEE standard known as the 802.1q standard. This standard
was originally written to define the operation of VLAN bridges that
permit the definition, operation and administration of VLAN
topologies within a bridged LAN infrastructure. In particular, the
standard specifies the contents of a tag field containing VLAN
information that can be inserted into an Ethernet frame. If a port
has an 802.1q-compliant device attached (such as a network switch
or router), these tagged frames can carry VLAN membership
information, such as an ID that identifies the VLAN, which allows
the device to apply restrictions associated with that VLAN by
permitting or denying the tagged frame to pass through the
device.
[0039] In accordance with this VLAN tagging embodiment, in step
310, the policy server would retrieve a VLAN tag from the privilege
database and in steps 312 and 314, this VLAN tag would be provided
to the access server 210, which, in turn, would cause the access
point to which the client device is connected to apply that VLAN
tag to all data packets sent from that device. Then, as previously
mentioned, the VLAN tag will cause the other inline components to
apply the policy by permitting or denying the tagged frame to pass
through the component. When the device moves to a different
location, it may be assigned to a new VLAN by changing the VLAN
tag. This new VLAN may have different privileges and
restrictions.
[0040] Typically, a new network address must be assigned to a
client device when it changes from one VLAN to another VLAN. In
order to avoid this change in the network address, it is also
possible in another embodiment to assign each client device to a
VLAN that is dedicated to that device. Then privileges and
restrictions for a device are changed by changing the privileges
and restrictions assigned to the VLAN dedicated to that device.
[0041] In still another embodiment, after the privilege information
has been applied, each access point then periodically polls the
access server to verify that the appropriate access permissions are
still in place. Therefore, when a device changes its user
credentials, its location (by moving) or its access point, the
access restrictions can be changed appropriately. Similarly, if the
policy for the combination of the device, user, location and access
change, the restrictions would change to conform. In some cases,
when enough information has not been collected to accurately
determine the location of the device, the device would be assigned
temporarily a default set of permissions.
[0042] In yet additional embodiments, the access server could
either publish privilege information to all access points or could
notify the access points of changes to the access permissions
asynchronously. In other embodiments, the access point or another
gateway device could determine the location of the wireless client
instead of the location system running in a server. Further,
instead of the access point applying any restrictions, any device,
such as a switch, router or gateway, in the data path could control
access. In addition, instead of applying network restrictions via
an 802.1q VLAN tag, the restrictions could instead be applied
through a stateful packet filter.
[0043] A software implementation of the above-described embodiment
may comprise a series of computer instructions either fixed on a
tangible medium, such as a computer readable media, for example, a
diskette, a CD-ROM, a ROM memory, or a fixed disk, or transmittable
to a computer system, via a modem or other interface device over a
medium. The medium either can be a tangible medium, including but
not limited to optical or analog communications lines, or may be
implemented with wireless techniques, including but not limited to
microwave, infrared or other transmission techniques. It may also
be the Internet. The series of computer instructions embodies all
or part of the functionality previously described herein with
respect to the invention. Those skilled in the art will appreciate
that such computer instructions can be written in a number of
programming languages for use with many computer architectures or
operating systems. Further, such instructions may be stored using
any memory technology, present or future, including, but not
limited to, semiconductor, magnetic, optical or other memory
devices, or transmitted using any communications technology,
present or future, including but not limited to optical, infrared,
microwave, or other transmission technologies. It is contemplated
that such a computer program product may be distributed as a
removable media with accompanying printed or electronic
documentation, e.g., shrink wrapped software, pre-loaded with a
computer system, e.g., on system ROM or fixed disk, or distributed
from a server or electronic bulletin board over a network, e.g.,
the Internet or World Wide Web.
[0044] Although an exemplary embodiment of the invention has been
disclosed, it will be apparent to those skilled in the art that
various changes and modifications can be made which will achieve
some of the advantages of the invention without departing from the
spirit and scope of the invention. For example, it will be obvious
to those reasonably skilled in the art that, in other
implementations, other mechanisms for computing the location of the
wireless client and for granting privileges may be used. In
addition, although client server networks have been shown for
purposes of illustration, access policies could also be imposed on
network traffic on conventional mesh-style networks using the
principles of the invention. Other aspects, such as the specific
process flow and the order of the illustrated steps, as well as
other modifications to the inventive concept are intended to be
covered by the appended claims.
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