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

2. Rick Graziani graziani@cabrillo.edu2 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.

3. Rick Graziani graziani@cabrillo.edu3 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

4. Rick Graziani graziani@cabrillo.edu4 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

5. Rick Graziani graziani@cabrillo.edu5 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.

6. 802.11 Standards

7. Rick Graziani graziani@cabrillo.edu7 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

8. Rick Graziani graziani@cabrillo.edu8 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,

9. Rick Graziani graziani@cabrillo.edu9 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

10. Rick Graziani graziani@cabrillo.edu10 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)

11. Overview of WLAN Topologies IBSS BSS ESS Access Points Quick Preview: Station/AP Connectivity

12. Rick Graziani graziani@cabrillo.edu12 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.

13. Rick Graziani graziani@cabrillo.edu13 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.

14. Rick Graziani graziani@cabrillo.edu14 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).

15. Rick Graziani graziani@cabrillo.edu15 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).

16. Rick Graziani graziani@cabrillo.edu16 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)

17. Rick Graziani graziani@cabrillo.edu17 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

18. Rick Graziani graziani@cabrillo.edu18 Quick Preview: Station/AP Connectivity 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

19. Rick Graziani graziani@cabrillo.edu19 Quick Preview: Station/AP 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)

20. Rick Graziani graziani@cabrillo.edu20 Quick Preview: Station/AP Connectivity 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)

21. Rick Graziani graziani@cabrillo.edu21 Quick Preview: Station/AP Connectivity The Cisco APs have the default SSID tsunami. SSID

22. Rick Graziani graziani@cabrillo.edu22 Quick Preview: Station/AP Connectivity Using Windows Using NetStumbler Looking for an AP? Right click

23. Rick Graziani graziani@cabrillo.edu23 Quick Preview: Station/AP Connectivity 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

24. 802.11 Medium Access Mechanisms DCF Operations Hidden Node Problem RTS/CTS Frame Fragmentation

25. Rick Graziani graziani@cabrillo.edu25 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 LLCLLC

26. Rick Graziani graziani@cabrillo.edu26 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)

27. Rick Graziani graziani@cabrillo.edu27 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

28. Rick Graziani graziani@cabrillo.edu28 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

29. Rick Graziani graziani@cabrillo.edu29 DCF IEEE mandated access mechanism for 802.11 is DCF (Distributed Coordination Function) –Basis for CSMA/CA –Discussed in detail next

30. Rick Graziani graziani@cabrillo.edu30 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!

31. Rick Graziani graziani@cabrillo.edu31 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) An example will be coming !

32. Rick Graziani graziani@cabrillo.edu32 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. General 802.11 Frame (more on this later) An example will be coming !

33. Rick Graziani graziani@cabrillo.edu33 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)

34. Rick Graziani graziani@cabrillo.edu34 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. An example will be coming !

35. Rick Graziani graziani@cabrillo.edu35 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

36. Rick Graziani graziani@cabrillo.edu36 Wanting to transmit (2/3) (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

37. Rick Graziani graziani@cabrillo.edu37 Wanting to transmit (3/3) 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. General 802.11 Frame (more on this later) Others update NAV

38. Rick Graziani graziani@cabrillo.edu38 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

39. Rick Graziani graziani@cabrillo.edu39 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

40. Rick Graziani graziani@cabrillo.edu40 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)

41. Rick Graziani graziani@cabrillo.edu41 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. General 802.11 Frame (more on this later) Others update NAV Martha and George receive “broadcast- based” 802.11 frame. ( ( () ) )

42. Rick Graziani graziani@cabrillo.edu42 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!

43. Rick Graziani graziani@cabrillo.edu43 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!

44. Rick Graziani graziani@cabrillo.edu44 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)

45. 802.11 Medium Access Mechanisms DCF Operations Hidden Node Problem RTS/CTS Frame Fragmentation

46. Rick Graziani graziani@cabrillo.edu46 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.

47. Rick Graziani graziani@cabrillo.edu47 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

48. Rick Graziani graziani@cabrillo.edu48 Hidden Node Problem Solutions: –Move the node –Remove the obstacle –Use RTS/CTS (Request to Send / Clear to Send)

49. 802.11 Medium Access Mechanisms DCF Operations Hidden Node Problem RTS/CTS Frame Fragmentation

50. Rick Graziani graziani@cabrillo.edu50 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.

51. Rick Graziani graziani@cabrillo.edu51 RTS/CTS Solution The CTS is sent to the AP’s entire coverage area

52. Rick Graziani graziani@cabrillo.edu52 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.

53. Rick Graziani graziani@cabrillo.edu53 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

54. Rick Graziani graziani@cabrillo.edu54 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.

55. Rick Graziani graziani@cabrillo.edu55 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.

56. Rick Graziani graziani@cabrillo.edu56 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

57. 802.11 Medium Access Mechanisms DCF Operations Hidden Node Problem RTS/CTS Frame Fragmentation

58. Rick Graziani graziani@cabrillo.edu58 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.

59. Rick Graziani graziani@cabrillo.edu59 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.”

60. Rick Graziani graziani@cabrillo.edu60 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.

61. Rick Graziani graziani@cabrillo.edu61 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… S etting 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.

62. Rick Graziani graziani@cabrillo.edu62 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

63. Rick Graziani graziani@cabrillo.edu63 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.

64. Client Adapters 2.4 Online Curriculum

65. Rick Graziani graziani@cabrillo.edu65 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.

66. Rick Graziani graziani@cabrillo.edu66 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.

67. Rick Graziani graziani@cabrillo.edu67 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.

68. Rick Graziani graziani@cabrillo.edu68 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.

69. Rick Graziani graziani@cabrillo.edu69 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.

70. Rick Graziani graziani@cabrillo.edu70 Cisco Aironet 5 GHz 54 Mbps WLAN card 802.11a IEEE 802.11a-compliant CardBus Type II adapter.

71. Rick Graziani graziani@cabrillo.edu71 Parts of the client adapter

72. Rick Graziani graziani@cabrillo.edu72 LED Status

73. Rick Graziani graziani@cabrillo.edu73 Windows Drivers

74. Rick Graziani graziani@cabrillo.edu74 Linux and Macintosh Drivers

75. Rick Graziani graziani@cabrillo.edu75 Downloading Drivers and Software http://www.cisco.com/public/sw-center/sw-wireless.shtml

76. Rick Graziani graziani@cabrillo.edu76 IBSS (Ad-Hoc ) or BSS (Infrastructure) Client adapters work in both IBSS and BSS networks.

77. Aironet Client Utility (ACU)

78. Rick Graziani graziani@cabrillo.edu78 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.

79. Rick Graziani graziani@cabrillo.edu Aironet Client Utility: Main Screen

80. Rick Graziani graziani@cabrillo.edu80 Windows CE, OS X, and Linux

81. Rick Graziani graziani@cabrillo.edu Aironet Client Utility: Loading Firmware

82. Rick Graziani graziani@cabrillo.edu Aironet Client Utility: Profile Manager

83. Rick Graziani graziani@cabrillo.edu83 Aironet Client Utility: Adding a Profile

84. Rick Graziani graziani@cabrillo.edu84 Profile: System Parameters

85. Rick Graziani graziani@cabrillo.edu85 Profile: RF Network

86. Rick Graziani graziani@cabrillo.edu86 Profile: Advanced (Infrastructure)

87. Rick Graziani graziani@cabrillo.edu87 Profile: Advanced (Ad Hoc)

88. Rick Graziani graziani@cabrillo.edu88 Profile: Network Security

89. Rick Graziani graziani@cabrillo.edu89 Auto Profile

90. Rick Graziani graziani@cabrillo.edu90 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.

91. Rick Graziani graziani@cabrillo.edu91 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.

92. Rick Graziani graziani@cabrillo.edu92 Aironet Client Monitor (ACM)

93. Rick Graziani graziani@cabrillo.edu93 Aironet Client Monitor (ACM) Right Click

94. ACU Monitoring and Troubleshooting Tools

95. Rick Graziani graziani@cabrillo.edu Aironet Client Utility: Status

96. Rick Graziani graziani@cabrillo.edu Aironet Client Utility: Statistics

97. Rick Graziani graziani@cabrillo.edu Aironet Client Utility: Link Test

98. Rick Graziani graziani@cabrillo.edu Aironet Client Utility: Site Survey

99. Rick Graziani graziani@cabrillo.edu Link Status Meter

100. Installing the ACU Software

101. Rick Graziani graziani@cabrillo.edu101 Installing the Client Adapter Insert the adapter card into the PCMCIA slot in the PC

102. Rick Graziani graziani@cabrillo.edu102 ACU Install and Setup From the UTILS folder on the driver CD, run SETUP SETUP

103. Rick Graziani graziani@cabrillo.edu103 ACU Install and Setup (cont.)

104. Rick Graziani graziani@cabrillo.edu104 ACU Install and Setup (cont.)

105. Rick Graziani graziani@cabrillo.edu105 ACU Install and Setup (cont.)

106. Rick Graziani graziani@cabrillo.edu106 ACU Install and Setup (cont.)

107. Rick Graziani graziani@cabrillo.edu107 ACU Install and Setup (cont.) Aironet Client Utility (ACU)

108. Rick Graziani graziani@cabrillo.edu108 ACU Install and Setup (cont.) Step 14

109. Rick Graziani graziani@cabrillo.edu109 ACU Install and Setup (cont.)

110. Ch. 2 – 802.11 and NICs Part 1 – 802.11 MAC and Cisco Client Adapters Cisco Fundamentals of Wireless LANs version 1.1 Rick Graziani Cabrillo College