Ch. 2 – 802.11 and NICs Part 1 – 802.11 MAC and Cisco Client Adapters Cisco Fundamentals of Wireless LANs version 1.2

Ch. 2 – 802.11 and NICsPart 1 – 802.11 MAC and Cisco Client

Adapters

Cisco Fundamentals of Wireless LANs version 1.2

Rick Graziani [email protected] 2

Overview

• Sections 2.2 and 2.3 – We will not use most of the online curriculum in these

sections.– This presentation will add additional material.– However, still please read the online curriculum.

Will not use curriculum. Additional information provided.

MAC – Two presentations. This is Part I PHY – Separate presentation.


802.11 Overview and MAC Layer

Part 1 – 802.11 MAC and Cisco Client Adapters

• 2.1 Online Curriculum– 802.11 Standards

• Overview of WLAN Topologies– IBSS– BSS– ESS– Access Points

• 802.11 Medium Access Mechanisms– DCF Operations– Hidden Node Problem– RTS/CTS– Frame Fragmentation

• 2.4 – 2.6 Online Curriculum– Client Adapters– Aironet Client Utility (ACU)– ACU Monitoring and

Troubleshooting Tools

Part 2 – 802.11 MAC• (Separate Presentation)

• 802.11 Data Frames and Addressing

• 802.11 MAC Layer Operations– Station Connectivity– Power Save Operations– 802.11 Frame Formats

• Non-standard devices


Recommended Reading and Sources for this Presentation

• To understand WLANs it is important to understand the 802.11 protocols and their operations.

• These two books do an excellent job in presenting this information and is used throughout this and other presentations.

Matthew S. Gast

ISBN: 0596001835

Pejman Roshan Jonathan Leary

ISBN: 1587050773


Acknowledgements

• Thanks to Pejman Roshan and Jonathan Leary at Cisco Systems, authors of 802.11 Wireless LAN Fundamentals for allowing me to use their graphics and examples for this presentation.

• Also thanks to Matthew Gast for author of 802.11 Wireless Networks, The Definitive Guide for allowing me to use their graphics and examples for this presentation.

802.11 Standards


Overview of Standardization

• Standardization of networking functions has done much to further the development of affordable, interoperable networking products.

• This is true for wireless products as well. • Prior to the development of standards, wireless systems were plagued

with low data rates, incompatibility, and high costs. • Standardization provides all of the following benefits:

– Interoperability among the products of multiple vendors – Faster product development – Stability – Ability to upgrade – Cost reductions


IEEE and 802.11

• IEEE, founded in 1884, is a nonprofit professional organization

• Plays a critical role in developing standards, publishing technical works, sponsoring conferences, and providing accreditation in the area of electrical and electronics technology.

• In the area of networking, the IEEE has produced many widely used standards such as the 802.x group of local area network (LAN) and metropolitan area network (MAN) standards,


IEEE 802 Architecture

Some you may recognize:

• 802.3 – CSMA/CD (Carrier Sense Multiple Access with Collision Detection), often mistakenly called Ethernet

• 802.1d – Spanning Tree

• 802.1Q – VLANs

• 802.5 – Token Ring


IEEE 802.11 Architecture

• 802.11 is a family of protocols, including the original specification, 802.11, 802.11b, 802.11a, 802.11g and others.

• Officially called the IEEE Standard for WLAN MAC and PHY specifications.

• 802.11 “is just another link layer for 802.2”• 802.11 is sometimes called wireless Ethernet, because of its shared

lineage with Ethernet, 802.3.• The wired network side of the network could be Ethernet, Token Ring,

etc.(we will always use Ethernet in our examples)• Access Points and Bridges act as “translation bridges” between

802.11 and 802.3 (or other other protocol)

Overview of WLAN Topologies

IBSS

BSS

ESS

Access Points

Quick Preview: Station/AP Connectivity


Overview of WLAN Topologies

• Three types of WLAN Topologies:– Independent Basic Service Sets (IBSS)– Basic Service Set (BSS)– Extended Service Set (ESS)

• Service Set – A logical grouping of devices.• WLANs provide network access by broadcasting a signal across a wireless

radio frequency.• Transmitter prefaces its transmissions with a Service Set Identifier (SSID)• A station may receive transmissions from transmitters with the same or

different SSIDs.


Independent Basic Service Sets (IBSS)

• IBSS consists of a group of 802.11 stations directly communicating with each other.

• No Access Point used

• Also known as an ad-hoc network.

• Usage: Few stations setup up for a specific purpose for a short period of time. (ex. file transfers.)

• We will have a an IBSS lab, but our main focus will be BSSs and ESSs.


Basic Service Set (BSS)

• BSS, also known as an Infrastructure BSS (never called IBSS)

• Requires an Access Point (AP)– Converts 802.11 frames to Ethernet and visa versa– Known as a translation bridge

• Stations do not communicate directly, but via the AP

• APs typically have an uplink port that connects the BSS to a wired network (usually Ethernet), known as the Distribution System (DS).


Extended Service Set (ESS)

• Multiple BSSs can be connected together with a layer 2 “backbone network” to form an Extended Service Set (ESS).

• 802.11 does not specify the backbone network

• The backbone network is also known as the Distribution System (DS) and could be wired or wireless.

• Stations are “associated” with only one AP at a time.

• The SSID is the same for all BSS areas in the ESS (unless creating multiple BSSs, i.e. one for Marketing and another for Sales).


• What if you want to be able to move between access points without the latency of re-association and re-authentication (these will be explained)?

• Roaming gives stations true mobility allowing them to move seamlessly between BSSs. (More later)

• APs need to be able to communicate between themselves since stations can only associate with one AP at a time.

• IEEE 802.11 working group (Task Group F) is working on standardizing IAPP (Inter-Access Point Protocol)

Extended Service Set (ESS)


Access Points

• Access Point (AP)– Translates (converts) 802.11 frames to Ethernet and

visa versa– Typically provides wireless-to-wired bridging function– All BSS communications must go through the AP, even

between two wireless stations



• This is just a preview.

• Later in this module, we will take a closer look at the following:

– The hardware/software:• Wireless NICs• Client Utilities (Aironet)• Using Windows to set the

IP Address

– The 802.11 MAC Layer Operations:

• Station Connectivity



SSID (Service Set Identifier)

• At a minimum a client station and the access point must be configured to be using the same SSID.

• An SSID is:– Between 2 and 32

alphanumeric characters– Spaces okay– Must match EXACTLY,

including upper and lower case

– Sometimes called the ESSID– Not the same as BSSID (MAC

address of the AP, later)



• SSIDs are sent by the APs in beacons (and other frames)

• Applications such as NetStumbler or even Windows can see these beacons and interpret the information in them.

Can use windows to configure wireless NIC, but we will use the Cisco client utility, Aironet

SSID 2 and 3 are used for roaming where different SSIDs are used (later)



• The Cisco APs have the default SSID tsunami.

SSID



Using Windows

Using NetStumbler

Looking for an AP?

Right click



• Your operating system (Windows) or wireless NIC client (Aironet) will tell you whether or not you have successfully connected (associated).

Windows Toolbar Icon

Aironet Toolbar Icon

Windows Network Properties

802.11 Medium Access Mechanisms

DCF Operations

Hidden Node Problem

RTS/CTS

Frame Fragmentation


802.11 Frames – This isn’t Ethernet (802.3)

• 802.11 has some similarities with Ethernet but it is a different protocol.• Access Points are translation bridges.• From 802.11 to Ethernet, and from Ethernet to 802.11• The “data/frame body” is re-encapsulated with the proper layer 2 frame.• Certain addresses are copied between the two types of frames.

Distribution System (DS)

General 802.11 Frame

IP Packet

IP PacketLLC


802.11 Frames

802.11 Frames

• Data Frames (most are PCF)

– Data

– Null data

– Data+CF+Ack

– Data+CF+Poll

– Data+CF+Ac+CF+Poll

– CF-Ack

– CF-Poll

– CF-Cak+CF-Poll

• Control Frames

– RTS

– CTS

– ACK

– CF-End

– CF-End+CF-Ack

• Management Frames

– Beacon

– Probe Request

– Probe Response

– Authentication

– Deauthentication

– Association Request

– Association Response

– Reassociation Request

– Reassociation Response

– Disassociation

– Traffic Indication Map (TIM)


Medium Access – CSMA/CA

• Both CSMA/CD and CSMA/CA are half-duplex architectures

• Ethernet uses CSMA/CD – Collision Detection– Ethernet devices detect a collision as when the data is transmitted

• 802.11 uses CSMA/CA – Collision Avoidance– 802.11 devices only detect (assume) a collision when the

transmitter has not received an Acknowledgement.– Stations also use a virtual carrier-sense function, NAV

CSMA/CD CSMA/CA

ACK

All stations detect the collision


Medium Access – CSMA/CA

• The 802.11 standard makes it mandatory that all stations implement the DCF (Distributed Coordination Function), a form of carrier sense multiple access with collision avoidance (CSMA/CA). More Coming!

• CSMA is a contention-based protocol making sure that all stations first sense the medium before transmitting (physically and virtually). More Coming!

• The main goal of CSMA/CA is to avoid having stations transmit at the same time, which will then result in collisions and eventual retransmissions. However, collisions may still occur and when they do stations may or may not be able to detect them (hidden node problem). More Coming!

CSMA/CD CSMA/CA

ACK

All stations detect the collision


DCF

• IEEE mandated access mechanism for 802.11 is DCF (Distributed Coordination Function)– Basis for CSMA/CA– Discussed in detail next


DCF Operation

• In DCF operation, a station wanting to transmit :– Checks to see if radio link is clear, CS/CCA – Carrier Sense,

Clear Channel Assessment (Later in PHY presentation)– Checks its NAV timer (coming) to see if someone else is using the

medium.– If medium is available DCF uses a random backoff timer to avoid

collisions and sends the frame.• Transmitting station only knows the 802.11 frame got there if it

receives an ACK.• May also use RTS/CTS to reduce collisions (coming)

An example will be coming!


Duration Field

• Duration/ID field – The number of microseconds (millionth of a second) that the medium is expected to remain busy for transmission currently in progress.– Transmitting device sets the Duration time in microseconds.– Includes time to:

• Transmit this frame to the AP (or to the client if an AP)• The returning ACK • The time in-between frames, IFS (Interframe Spacing)

• All stations monitor this field!• All stations update their NAV (Network Allocation Vector) timer.

General 802.11 Frame (more on this later)



NAV Timer

• All stations have a NAV (Network Allocation Vector) timer.• Virtual carrier-sensing function• Protects the sequence of frames from interruption.• Martha sends a frame to George.• Since wireless medium is a “broadcast-based” (not broadcast frame) shared

medium, all stations including Vivian receive the frame.• Vivian updates her NAV timer with the duration value.• Vivian will not attempt to transmit until her NAV is decremented to 0.• Stations will only update their NAV when the duration field value received is

greater than their current NAV.




Broadcast-based shared medium

• Host A is sending 802.11 frames to another host via the AP.

• All other 802.11 devices in BSS (on this channel) and within range of the signal will see the frame.

• 802.11 framing provides addressing, so only the AP knows it is the next-hop receiver.

• Other 802.11 devices within this BSS can sense that the medium is in use and will update their NAV values. What if a station is in range of the AP but not

the Host A? (Hidden node problem – later)


Interframe Spacing (IFS)

• 802.11 uses four different interframe spaces used to determine medium access (note: microsecond = millionth of a second):– DIFS – DCF Interframe Space

• Minimum amount of medium idle time until contention-based services begin.

– PIFS – PCF Interframe Space • Used by PCF

– SIFS – Short Interframe Space • Used for highest priority transmission, ACKs, RTS, CTS

– EIFS – Extended Interframe Space• Not a fixed interval and used only when there is an error in frame

transmission.



Wanting to transmit (1/3)

• Station wanting to transmit.

• Carrier Sensing:

– Physical: Physically senses medium is idle (CS/CCA – coming).

– Virtual: NAV timer is 0

• Waits DIFS (DCF Interframe Space)

– Minimum amount of medium idle time until contention-based services begin.

– Once DCF is over, stations can contend for access.

• Contention window begins.

– Uses random backoff algorithm to determine when it can attempt to access the medium. (next)

Random backoff slots



• (Detail of random backoff algorthim has been left out, but this will be sufficient.)

• The random backoff algorithm randomly selects a value from 0 to 255 (maximum value varies by vendor and stored in the NIC).

• The random value is the number of 802.11 slot times the station must wait after the DIFS, during the contention window before it may transmit.

• Stations pick a random slot and wait for that slot before attempting to access the medium.

• With several stations attempting to transmit, the station that picks the lowest slot, lowest random number, wins.

Contention Window Begins



• Station transmits, setting the Duration ID to the time needed to transmit data, ACK and IFSs.

• Other stations with higher slots will see the new transmission and wait to transmit.

• If frame arrives at AP (assuming the transmitter is a station), then an ACK will be returned (stations have updated their NAVs from original frame).

• If there is not an ACK received, the sending station assumes there has been a collision (stations have not updated their NAVs because of collision).– If two stations have the same lowest slot time and both transmit, then a

collision occurs.• Stations will update its retry counter (double) to determine a new randomly

selected slot time and process starts all over again.


Others update NAV


Example

Scenario:

• Both Vivian and George want to transmit frames.

• Both stations have same NAV values and physically sense when the medium is idle.

• Both are waiting for Martha’s transmission to end and the medium to become available.

• The medium now becomes available.

I’m waiting

I’m waiting


Example

• George and Vivian are both wanting to transmit.

• Both perform the following:

• Both sense that medium is available using Physical and Virtual Carriers Sensing:– Physical: Physically senses medium is idle (CS/CCA – coming).– Virtual: NAV timer is 0

• Both waits DIFS (DCF Interface Space)

• Contention window begins.– Uses random backoff algorithm to determine when it can attempt

to access the medium. (next)

Random backoff slots


Example

• Both Vivian and George calculate their random backoff algorithm to randomly selects a value from 0 to 255.

• Vivian has a slot time of 7, George a slot time of 31.

• Vivian wins.

• The destination of her frame is George (could have been a station on the wired network.)

Vivian (7), George (31)


Example

• Vivian transmits, setting the Duration ID to the time needed to transmit data, ACK and IFSs.

• George with a higher slot will see the 802.11 frame from Vivian and wait to transmit.

• Assuming their was not a collision from another station, Martha and George update their NAVs.


Others update NAV

Martha and George receive “broadcast-based” 802.11 frame.

( ( ( ) ) )


Example

• The frame arrives at the AP.• After the SIFS, the AP sends an ACK back to Vivian, which is how Vivian

knows the frame was received by the AP.• The AP now has the frame and must contend for access to the medium

like all other stations.• Once it sends the frame to George, George will send an ACK back to the AP.• Remember, 802.11 uses a half-duplex, shared medium and the AP has to

contend for access just like all other devices!


Your turn!

• Get into teams of 2.

• Each person is a wireless client contending for access to shared wireless medium.

• Using the example as an example contend for the wireless medium.

• Station 1: Backoff slot of 3

• Station 2: Backoff slot of 9

• Go through the steps of sending the 802.11 frame to the AP– Use a total NAV value of 1054 microseconds for both stations.

• Answer is on the next slide! Don’t look until you need to check!


Your turn! (Solution)

1. Both stations count down their NAV timers to 0

2. Both stations physically sense the wireless medium is available

3. Both stations wait the DIFS

4. Station 1 and Station 2 prepare to send their 802.11 by updating the NAV value in the Duration/ID field to reflect the time needed to transmit to the AP, the ACK from the AP and IFS for both the originally

transmitted frame and the ACK from the AP. 5. Station 1 sends its 802.11 frame first because it had to wait less time

with a Backoff slot of 3.

6. Station 2 “sees” that Station 1 has accessed the shared medium, the 802.11 frame from Station 1 to the AP, and updates its NAV timer.

7. Station 2 waits for the NAV timer to count down to 0. (Step 1)


DCF Operations

Hidden Node Problem

RTS/CTS

Frame Fragmentation


Hidden Node Problem

• What if a station is in range of the AP but not other hosts, like the transmitting host?

• Wireless networks have fuzzy boundaries, sometimes where may not be able to communicate/see every other node.

• Hidden nodes can be caused by:– Hosts are in range of the AP but not each other.– An obstacle is blocking the signal between the hosts.


Hidden Node Problem

• The problem is collisions.– Collisions occur at the AP (or another station in an IBSS).– Both stations assume the medium is clear and transmit near the

same time, resulting in a collision.– The AP cannot properly receive either signal and will not ACK

either one.– Both stations retransmit, resulting in more collisions.

• Throughput is significantly reduced


Hidden Node Problem

• Solutions:– Move the node– Remove the obstacle– Use RTS/CTS (Request to Send / Clear to Send)


DCF Operations

Hidden Node Problem

RTS/CTS

Frame Fragmentation


RTS/CTS Solution

• The hidden node stations cannot see the RTS.

• The AP replies to Vivian with a CTS, which all nodes, including the hidden node can see.

• Vivian transmits the frame.

• The AP returns an ACK to Vivian.

• The AP sends the message to George who returns an ACK to the AP.

• Vivian attempts to reserve the medium using an RTS control frame to the AP.

• The RTS frame indicates to the AP and all stations within range, that Vivian wants to reserve the medium for a certain duration of time, message, ACK, and SIFS.


RTS/CTS Solution

The CTS is sent to the AP’s entire coverage area


RTS/CTS Solution

• The RTS/CTS procedure can be enabled/controlled by setting the RTS threshold on the 802.11 client NIC.

• RTS/CTS is also used during frame fragmentation (coming).

• RTS/CTS consumes a fair amount of capacity and overhead, resulting in additional latency.

• Normally used in high capacity environments.


Setting the RTS Threshold on a Cisco Client

• Specifies the data packet size beyond which the low-level RF protocol invokes RTS/CTS flow control. A small value causes RTS packets to be sent more often, which consumes more of the available bandwidth and reduces the throughput of other network packets.

• However, small values help the system recover from interference or collisions.

RTS Threshold


Improving WLAN Performance with RTS/CTS by Jim Geier (wi-fiplanet.com)

• If you enable RTS/CTS on a particular station (just the hidden node station), it will refrain from sending a data frame until the station completes a RTS/CTS handshake with another station, such as an access point.

• Keep in mind, though, that an increase in performance using RTS/CTS is the net result of introducing overhead (i.e., RTS/CTS frames) and reducing overhead (i.e., fewer retransmissions). If you don't have any hidden nodes, then the use of RTS/CTS will only increase the amount of overhead, which reduces throughput. A slight hidden node problem may also result in performance degradation if you implement RTS/CTS. In this case, the additional RTS/CTS frames cost more in terms of overhead than what you gain by reducing retransmissions. Thus, be careful when implementing RTS/CTS.


Improving WLAN Performance with RTS/CTS by Jim Geier (wi-fiplanet.com)

• One of the best ways to determine if you should activate RTS/CTS is to monitor the wireless LAN for collisions. If you find a large number of collisions and the users are relatively far apart and likely out of range, then try enabling RTS/CTS on the applicable user wireless NICs. You can activate the function by clicking "enable RTS/CTS" somewhere in the user setup screens. You don't need to enable RTS/CTS at the access point in this case. After receiving a RTS frame from a user's radio NIC, the access point will always respond with a CTS frame.

• Of course, keep in mind that user mobility can change the results. A highly mobile user may be hidden for a short period of time, perhaps when you perform the testing, then be closer to other stations most of the time. If collisions are occurring between users within range of each other, the problem may be the result of high network utilization or possibly RF interference.


RTS/CTS Example

• Stations C, D, E, and F can see traffic (signals) from all stations including HN-A and HN-B (and visa versa).

• HN-A and HN-B can not see each other, but can communicate with the AP.

• RTS/CTS is enabled on HN-A and HN-B, so that the AP will respond with a CTS that the other HN station will see.

• If it wasn’t for the other HN station, neither HN would need RTS/CTS

HN-A RTS/CTS

HN-B RTS/CTS

C

D

E

F

AP


DCF Operations

Hidden Node Problem

RTS/CTS

Frame Fragmentation


Frame Fragmentation

• Since we have already discussed RTS/CTS, let’s also discuss frame fragmentation.

• Later, we will see that RTS/CTS and fragmentation are typically combined.

• Frame fragmentation is a MAC layer function that is designed to increase the reliability of transmitting frames across a wireless medium.


Frame Fragmentation

• In a “hostile wireless medium” (interference, noise) larger frames may have more of a problem reaching the receiver without any errors.

• By decreasing the size of the frame, the probability of interference during transmission can be reduced.

• Breaking up a large frame into smaller frames, allows a larger percentage of frames to arrive undamaged (without errors).

• “Easier to poor sand down a hole than boulders.”


Frame Fragmentation

• Frame fragmentation can increase the reliability of frame transmissions but there is additional overhead:– Each frame fragment includes the 802.11 MAC protocol header.– Each frame fragment requires a corresponding acknowledgement.

• If a frame fragment encounters errors or a collision, only that fragment needs to be retransmitted, not the entire frame.

• The frame control field includes information that this is a fragmented frame.


Frame Fragmentation

• The “network administrator” (user) can define the fragment size.

• Fragment size – The largest packet that the client adapter sends without fragmenting the packet.

• Only unicast packets will be fragmented, not broadcasts or multicasts.

• WiFiPlanet.com: “The fragment size value can typically be set between

256 and 2,048 bytes… Setting the threshold to the largest value (2,048 bytes) effectively disables fragmentation”

Fragment Threshold:

Defines the largest RF packet that the client adapter sends without splitting the packet into two or more smaller fragments. If a single fragment experiences interference during transmission, only that fragment must be resent. Fragmentation generally reduces throughput because the packet overhead for each fragment consumes a higher portion of the RF bandwidth.


Frame Fragmentation

• Frame fragments are sent in a burst, using a single iteration of DCF to access the medium.

• In other words the NAV is set in the first fragment and later fragments to reserve the medium for the entire original frame.

• FYI – Some of the detail– The first frame sets the NAV to be long enough to include the

returning ACK, the next fragment, its ACK, and 3 SIFS.– The following frames set the NAV to include successive ACKs and

SIFS.

From 802.11 Wireless Networks, by Matthew Gast


Frame Fragmentation and RTS/CTS

• In practice, the RTS/CTS exchange is usually combined with frame fragmentation.

• Fragmented frames are usually quite long and therefore will benefit from the RTS/CTS process.

• This will ensure exclusive access to the medium, free from collisions with hidden nodes.

• Many vendors set the default fragmentation threshold to be identical to the RTS/CTS threshold, so when fragmentation occurs so does RTS/CTS.

Client Adapters

2.4 Online Curriculum


Introduction

• The Cisco Aironet Wireless WLAN Adapters are also referred to as client adapters.

• The client adapters are fully compatible when used in devices supporting Plug-and-Play (PnP) technology.

• The primary function of the client adapters is to transfer data packets through the wireless infrastructure.

• The adapters operate similarly to a standard network product except that the cable is replaced with a radio connection.


350 Series PC card

• 802.11b

• Integrated antenna.

• A PCMCIA card radio module can be inserted into any device equipped with an external Type II or Type III PC card slot.

• Host devices can include laptops, notebook computers, personal digital assistants, and hand-held or portable devices.


350 Series LM card

• 802.11b

• The 350 Series LM card client adapter, also referred to as an LM card.

• A PCMCIA card radio module, which can be inserted into any device equipped with an internal Type II or Type III PC card slot.

• The primary difference between this and the PC card adapter is that the LM card does not include a built-in antenna.


350 Series PCI client adapter

• 802.11b

• A client adapter card radio module, which can be inserted into any device equipped with an empty PCI expansion slot, such as a desktop computer.

• These cards are typically shipped with an antenna that attaches to an external connector.


350 Series Mini-PCI

• 802.11b

• The Mini-PCI is available to laptop manufacturers to provide integrated 802.11b support.

• The Mini-PCI is also used in the Cisco 1100 AP and 1200 AP to provide 802.11b.


Cisco Aironet 5 GHz 54 Mbps WLAN card

• 802.11a

• IEEE 802.11a-compliant CardBus Type II adapter.


Parts of the client adapter


LED Status


Windows Drivers


Linux and Macintosh Drivers


Downloading Drivers and Software

http://www.cisco.com/public/sw-center/sw-wireless.shtml


IBSS (Ad-Hoc ) or BSS (Infrastructure)

Client adapters work in both IBSS and BSS networks.

Aironet Client Utility (ACU)


ACU Overview

• The following slides are just an overview of the various ACU screens.

• We will discuss many of these features and settings during the semester.

• You will also be configuring many of these features and settings in the various labs.

Rick Graziani [email protected]

Aironet Client Utility: Main Screen


Windows CE, OS X, and Linux


Aironet Client Utility: Loading Firmware


Aironet Client Utility: Profile Manager


Aironet Client Utility: Adding a Profile


Profile: System Parameters


Profile: RF Network


Profile: Advanced (Infrastructure)


Profile: Advanced (Ad Hoc)


Profile: Network Security


Auto Profile


Auto Profile

• After creating profiles for the client adapter, they can be included in the profile manager's auto profile selection feature.

• Then when auto profile selection is enabled, the client adapter automatically selects a profile from the list of profiles that were included in auto profile selection and uses it to establish a connection to the network.

• This makes the wireless profile selection invisible to the user and improves the user experience.


Auto Profile

• This saves me time.

• At home I have a different SSID and I use WEP.

• LuLu Carpenters, has a different SSID and is open authentication (no WEP).

• This way I do not have to select a profile before I am connected, by I connect automatically.


Aironet Client Monitor (ACM)


Aironet Client Monitor (ACM)

Right Click

ACU Monitoring and Troubleshooting Tools


Aironet Client Utility: Status


Aironet Client Utility: Statistics


Aironet Client Utility: Link Test


Aironet Client Utility: Site Survey


Link Status Meter

Installing the ACU Software


Installing the Client Adapter

• Insert the adapter card into the PCMCIA slot in the PC


ACU Install and Setup

From the UTILS folder on the driver CD, run SETUP

SETUP


ACU Install and Setup (cont.)









• Aironet Client Utility (ACU)



Step 14



Ch. 2 – 802.11 and NICsPart 1 – 802.11 MAC and Cisco Client

Adapters

Cisco Fundamentals of Wireless LANs version 1.1

Rick Graziani

Cabrillo College

Documents

Ch. 2 – 802.11 and NICs Part 1 – 802.11 MAC and Cisco Client Adapters Cisco Fundamentals of Wireless LANs version 1.2