1. Redes Inalámbricas – Tema 2.C Wireless LANs: the IEEE 802.11 standards
The 802 wireless family
IEEE
The physical layer
The MAC layer
Quality of service: e
MIMO: n
Management tools

2. Redes Inalámbricas – Tema 2.C Wireless LANs: the IEEE 802.11 standards
The 802 wireless family
IEEE
The physical layer
The MAC layer
Quality of service: e
MIMO: n
Management tools

3. IEEE 802 Active Working Groups and Study Groups
802.1 Higher Layer LAN Protocols Working Group
Link Security Executive Committee Study Group is now part of 802.1
802.3 Ethernet Working Group
Wireless LAN Working Group
Wireless Personal Area Network (WPAN) Working Group
Broadband Wireless Access Working Group
Resilient Packet Ring Working Group
Radio Regulatory TAG
Coexistence TAG
Mobile Broadband Wireless Access (MBWA) Working Group
Media Independent Handoff Working Group
Wireless Regional Area Networks

4. Historical notes
The IEEE Working Group for WLAN Standards was created in 1997:
Defines the MAC and 3 different physical layers that work at 1Mbps and 2Mbps:
Infrared (IR) in base band
Frequency hopping spread spectrum (FHSS), band de 2,4 GHz
Direct sequence spread spectrum (DSSS), band de 2,4 GHz
IEEE Std b (September 1999):
Extension of DSSS; Up to 11 Mbps
IEEE Std a (December 1999):
A different physical layer (OFDM): Orthogonal frequency domain multiplexing
Up to 54 Mbps
IEEE Std g (June 2003)
...

5. Evolution of the IEEE 802.11 standard
OFFICIAL IEEE WORKING GROUP PROJECT TIMELINES
IN PROCESS  - Standards, Amendments, and Recommended Practices
802.11p: Inter car communications
Communication between cars/road side and cars/cars
Planned for relative speeds of min. 200km/h and ranges over 1000m
Usage of GHz band in North America
802.11s: Mesh Networking
Design of a self-configuring Wireless Distribution System (WDS) based on
Support of point-to-point and broadcast communication across several hops
802.11r: Faster Handover between BSS
Secure, fast handover of a station from one AP to another within an ESS
Current mechanisms (even newer standards like i) plus incompatible devices from different vendors are massive problems for the use of, e.g., VoIP in WLANs
Handover should be feasible within 50ms in order to support multimedia applications efficiently

6. Evolution of the IEEE 802.11 standard
Other interesting groups
802.11t: Performance evaluation of networks
Standardization of performance measurement schemes
802.11v: Network management
Extensions of current management functions, channel measurements
Definition of a unified interface
802.11w: Securing of network control
Classical standards like , but also i protect only data frames, not the control frames. Thus, this standard should extend i in a way that, e.g., no control frames can be forged.
Note: Not all “standards” will end in products, many ideas get stuck at working group
Standards are available here:

7. IEEE and WiFi
Wi-Fi is a set of standards for wireless networks based on IEEE specifications.
Wi-Fi is a trademark of the Wi-Fi Alliance (formerly the Wireless Ethernet Compatibility Alliance), the trade organization that tests and certifies that equipments meet the IEEE x standards.
The main problem which is intended to solve through normalization is compatibility. This means that the user is assured that all devices having the seal Wi-Fi can work together regardless of the manufacturer of each.
A complete list of devices that have the certification Wi-Fi:

8. Redes Inalámbricas – Tema 2.C Wireless LANs: the IEEE 802.11 standards
The 802 wireless family
IEEE
The physical layer
The MAC layer
Quality of service: e
MIMO: n
Management tools

9. Spread Spectrum Transmission

10. Comparison of Wireless Modulation Schemes
FHSS transmissions less prone to interference from outside signals than DSSS
WLAN systems that use FHSS have potential for higher number of co-location units than DSSS
DSSS has potential for greater transmission speeds over FHSS
Throughput much greater for DSSS than FHSS
Amount of data a channel can send and receive

11. Orthogonal Frequency Division Multiplexing (OFDM)
With multipath distortion, receiving device must wait until all reflections received before transmitting
Puts ceiling limit on overall speed of WLAN
OFDM: Send multiple signals at same time
High number of low BW ‘modems’ are used, each on a different sub channel
The ‘slow’ sub channels are multiplexed into a ‘fast’ combined channel
Error correction is done with FEC and bit stripping
Avoids problems caused by multipath distortion
Used in a networks

12. Notion of a channel Signal Power
It is common knowledge that wireless communication happens over a fixed set of frequencies, called a channel. Such a system makes efficient use of such spectrum while allowing for multiple parties to communicate on orthogonal or independent channels.
This figure shows the power spectral density of a transmission, or which frequency is being utilized with how much aggregate output power.
Wireless communication is carried over a set of frequencies called a channel
Thanks to: Mishra, Shrivastava, Banerjee, and Arbaugh, The University of Wisconsin, Madison

13. Available spectrum is typically divided into disjoint channels
Channels in Wireless
Channel A
Channel B
Channel C
Channel D
Fixed Block of Radio Frequency Spectrum
Given a fixed amount of RF spectrum, communication engineers divide it up into disjoint channels. Each channel carries some communication traffic independent of the rest. The capacity of the wireless
Available spectrum is typically divided into disjoint channels
Thanks to: Mishra, Shrivastava, Banerjee, and Arbaugh, The University of Wisconsin, Madison

14. Ideal Spectrum Usage
Channel A
Channel B
Power
Frequency
Use entire range of frequencies spanning a channel
Usage drops down to zero right outside a channel
Thanks to: Mishra, Shrivastava, Banerjee, and Arbaugh, The University of Wisconsin, Madison

15. Realistic Spectrum Usage
Channel A
Channel B
Real Usage
Wastage of spectrum
In reality, this is what communication circuits can achieve
Results in inefficient usage of spectrum
Thanks to: Mishra, Shrivastava, Banerjee, and Arbaugh, The University of Wisconsin, Madison

16. Realistic Spectrum Usage
Channel A
Channel B
Real Usage
Wastage of spectrum
Is it possible to eliminate such inefficiencies ?
Thanks to: Mishra, Shrivastava, Banerjee, and Arbaugh, The University of Wisconsin, Madison

17. Define a new channel Define a new channel as shown
Channel B
Channel A’
Define a new channel as shown
Overlaps with neighboring two channels
Called a `partially overlapped’ channel
Thanks to: Mishra, Shrivastava, Banerjee, and Arbaugh, The University of Wisconsin, Madison

18. Define a new channel Channel A’ would interfere with both A and B
Channel B
Channel A’
Channel A’ would interfere with both A and B
Is it possible to get any gains from using A, A’ and B ?
Thanks to: Mishra, Shrivastava, Banerjee, and Arbaugh, The University of Wisconsin, Madison

19. 802.11b Channels
In the UK and most of EU: 13 channels, 5MHz apart, – GHz
Each channel is 22MHz
Significant overlap
Best channels are 1, 6 and 11

20. An 802.11 Experiment Amount of Interference
Can we use channels 1, 3 and 6 without interference ?
Link A Ch 1
Link C Ch 6
Link B Ch 3
Ch 1
Ch 3
Ch 6
Amount of Interference
Thanks to: Mishra, Shrivastava, Banerjee, and Arbaugh, The University of Wisconsin, Madison

21. An 802.11 Experiment 35 meters 60 meters Link A Ch 1 Link B Ch X
Thanks to: Mishra, Shrivastava, Banerjee, and Arbaugh, The University of Wisconsin, Madison

22. IEEE 802.11b Data rate Transmission range Frequency Security
1, 2, 5.5, 11 Mbit/s, depending on SNR
User data rate max. approx. 6 Mbit/s
Transmission range
300m outdoor, 30m indoor
Max. data rate ~10m indoor
Frequency
Free 2.4 GHz ISM-band
Security
Limited, WEP insecure, SSID
Availability
Many products and vendors
Connection set-up time
Connectionless/always on
Quality of Service
Best effort, no guarantees (unless polling is used, limited support in products)
Manageability
Limited (no automated key distribution, sym. Encryption)
Pros
Many installed systems and vendors
Available worldwide
Free ISM-band
Cons
Heavy interference on ISM-band
No service guarantees
Relatively low data rate

23. IEEE 802.11a Data rate Transmission range Frequency Security
6, 9, 12, 18, 24, 36, 48, 54 Mbit/s, depending on SNR
User throughput (1500 byte packets): 5.3 (6), 18 (24), 24 (36), 32 (54)
6, 12, 24 Mbit/s mandatory
Transmission range
100m outdoor, 10m indoor
E.g., 54 Mbit/s up to 5 m, 48 up to 12 m, 36 up to 25 m, 24 up to 30m, 18 up to 40 m, 12 up to 60 m
Frequency
Free , , GHz ISM-band
Security
Limited, WEP insecure, SSID
Availability
Some products, some vendors
Connection set-up time
Connectionless/always on
Quality of Service
Best effort, no guarantees (same as all products)
Manageability
Limited (no automated key distribution, sym. Encryption)
Pros
Fits into 802.x standards
Free ISM-band
Available, simple system
Uses less crowded 5 GHz band
Higher data rates
Cons
Shorter range

24. IEEE 802.11g Ratified in June 2003 by the IEEE Standards Board
standard preliminary draft submitted in December 2001;
Uses the 2.4 GHz band
OFDM and codification PBCC
Backward compatibility IEEE b
They can co-exist in the same WLAN
New transmission speeds: 6, 9, 12, 18, 24, 36, 48 & 54 Mbps

25. Examples of the physical parameters of a real deviceal
DATA SHEET of a Cisco Aironet a/b/g CardBus Wireless LAN Client Adapter

26. WiFi and health
RFR's biological effects are measured in terms of specific absorption rate (SAR) -- how much energy is absorbed into human tissue -- which is expressed in Watts per kilogram (W/kg). A dangerous level (by U.S. standards) is considered to be anything above 0.08 W/kg. Thus far, RFR measurements for Wi-Fi, both at home and abroad, are a minute fraction of emissions that could amount to this level. Wi-Fi, in fact, emits less than other common sources of RFR like microwaves and mobile phones. Since mobile phones were recently cleared as a potential carcinogen by a comprehensive, long-term study conducted by the Danish Institute of Cancer Epidemiology in Copenhagen, it seems very unlikely that devices emitting a lower (and less frequent) level could be more dangerous.
By Naomi Graychase, January 12, 2007
More information:

27. Redes Inalámbricas – Tema 2.C Wireless LANs: the IEEE 802.11 standards
The 802 wireless family
IEEE
The physical layer
The MAC layer
Quality of service: e
MIMO: n
Management tools

28. Available architectures
Independent Basic Service Set (IBSS)
is the simplest of all IEEE networks in that no network infrastructure is required. As such, an IBSS is simply comprised of one or more Stations which communicate directly with each other.
Do not confuse it with ad hoc!!
infrastructure Basic Service Set (BSS)
Components:
Station (STA)
Access Point (AP) or Point Coordinator (PC)
Basic Service Set (BSS)
Extended Service Set (ESS)

29. The MAC basics CSMA/CA with binary exponential backoff
The protocol, at its minimum, consists of two frames: data and ack
Point Coordination Function (PCF)
Distributed Coordination Function (DCF)
MAC
Services without
contention
Services with
The 5 timing values:
Slot time
SIFS: short interframe space (< slot time)
PIFS: PCF interframe space (=SIFS+1slot)
DIFS: DCF interframe space (=SIFS+2slots)
EIFS: extended interframe space
DIFS
PIFS
SIFS
Contention window
defer access
busy medium
slot

30. DCF example
The backoff intervals are chosen within the contention window. That is in the interval [0, CW]
The CW can vary between 31 slots (CWmin) and 1023 slots (CWmax)
CW increases after a failed transmission and re-initialized after a successful transmission
B1 = 25
B2 = 20
B1 = 5
B2 = 15
data
wait
data
wait
B2 = 10
B1 and B2 are the backoff intervals in STA 1 and 2
CW = 31

31. A couple of problematic configurations
Exposed node
Hidden node A A B C B C D

32. Hidden nodes situations
MU3 cannot hear MU1 or MU2 because of the distance
The obstacle prevents MU1 and MU2 from hearing one another

33. RTS/CTS mechanism Based on the network allocation vector (NAV) source
DIFS+contention
source
RTS
data
SIFS
SIFS
SIFS
destination
CTS
ACK
DIFS
Other STA
NAV (RTS)
Contention window
NAV (CTS)
defer access

34. PCF: Point Coordination Function
Data+Poll
DATA+ACK
Beacon
ACK
Station 2 sets NAV(Network Allocation Vector)
CF-End
PIFS
SIFS
(no response) CP PC
STA1
Contention Free Period
STA2
NAV
Reset
Time
STA3
Station 3 is hidden to the PC, it does not set the NAV.
It continues to operate in DCF.
The beacons are used to maintain synchronization of the timers in the stations and to send control information
The AP generates the beacons at regular intervals
The stations know when the next beacon will arrive
the target beacon transmission time (TBTT) are announced in the previous beacon

35. Frames structure management (00) control (01), data (10),
Types of addresses:
Source address (SA)
Destination Address (DA)
Transmitter Address (TA)
Receiver Address (RA)
BSS identifier (BSSID)
management (00)
control (01),
data (10),
reserved (11) SA DA TA RA 1
Wireless DS -
RA = BSSID
To the AP
BSSID
RA = DA
From the AP
IBSS
Addr. 4
Addr. 3
Addr. 2
Addr. 1
From DS
To DS
Función

36. Addressing and DS bits AP Client Client Server Server DS RA (BSSID) TA
SA/TA AP AP SA RA
Client AP DA
Client DA
Server
Server SA DA TA RA 1
Wireless DS -
RA = BSSID
To the AP
BSSID
RA = DA
From the AP
IBSS
Addr. 4
Addr. 3
Addr. 2
Addr. 1
From DS
To DS
Función

37. Services The IEEE 802.11 architecture defines 9 services
Station services:
Authentication
Deauthentication
Privacy  WEP
Data delivery
Distribution services:
Association  generate a connection between a STA and a PC
Disassociation
Reassociation  like association but informing the previous PC
Distribution
integration
Similar to plugging in and out in a regular network

38. State variables and services
In a IBSS there is no auth. nor ass. Data service is allowed
State 1:
unauthenticated,
unassociated
Class 1
frames
Successful authentication
Deauthentication notification
State 2:
authenticated,
unassociated
Class 1 & 2 frames
Deauthentication notification
Successful authentication or reassociation
Disassociation notification
State 3:
authenticated,
associated
A STA can be authenticated by several AP but associated only with one AP
Class 1, 2 & 3 frames

39. BSSID y SSID BSSID (Basic Service Set Identity) SSID (Service Set ID)
BSS: MAC address of the AP
Ad-Hoc: 46 bits random number
SSID (Service Set ID)
Known as the Network Name because it is basically the name that identifies the WLAN
Lenght: 0~32 octets
0: it is the broadcast SSID
Used to distinguish WLAN among them
The access points and stations who want to connect to a single WLAN must use the same SSID

40. The Extended Service Set (ESS)
BSS AP
WLAN
LAN
Distribution System (DS)
Inter-acces point protocol (IAPP)

41. IAPP and the Task Group f
Scope of Project: to develop recommended practices for an Inter-Access Point Protocol (IAPP) which provides the necessary capabilities to achieve multi-vendor Access Point interoperability across a Distribution System supporting IEEE P Wireless LAN Links.
Purpose of  Project: ... including the concepts of Access Points and Distribution Systems. Implementation of these concepts where purposely not defined by P As based systems have grown in popularity, this limitation has become an impediment to WLAN market growth. This project proposes to specify the necessary information that needs to be exchanged between Access Points to support the P DS functions. The information exchanges required will be specified for, one or more Distribution Systems; in a manner sufficient to enable the implementation of Distribution Systems containing Access Points from different vendors which adhere to the recommended practices
Status
The F Recommendation has been ratified and published in 2003.
IEEE F was a Trial Use Recommended Practice. The IEEE 802 Executive Committee approved its withdrawal on February 03, 2006

42. Wireless Distribution System
IEEE , WDS means
Multiple wireless “ports” inside the access-point, to wirelessly interconnect cells (access-points connecting to other access-points)
pre-IEEE , did not support WDS:
Three ports exist in one access-point (one Ethernet, and two wireless cells)
One wireless backbone extension can be made (using two radio modules in the access-point)
WDS allows:
Extending the existing infrastructure with wireless backbone links
Totally wireless system without any wired backbones, needed in locations where large areas are to be covered and wiring is not possible

43. WDS examples Bridging two wired networks
As a repeater to extend a network

44. Operational processes Traffic flow - WDS operation
AP-1000 or AP-500
Bridge learn
table
STA-2
AP-1000 or AP-500 2
Bridge learn
table
Avaya Wireless PC-Card
STA-1 2
STA-2
Association table 2
Avaya Wireless PC-Card
STA-2
STA-1 2
Association table
Wireless Backbone
STA-1
WDS
Relay
Packet for STA-2
ACK
WDS
Relay
Packet for STA-2
ACK
Packet for STA-2
ACK
BSS-B
STA-2
STA-1
BSS-A

45. Linksys Wireless-G Access Point

46. Linksys Wireless-G Access Point

47. Linksys Wireless-G Access Point

48. Linksys Wireless-G Access Point

49. Linksys Wireless-G Access Point

50. Linksys Wireless-G Access Point

51. Linksys Wireless-G Access Point

52. Linksys Wireless-G Access Point

53. Linksys Wireless-G Access Point

54. Linksys Wireless-G Access Point

55. Linksys Wireless-G Access Point

56. Redes Inalámbricas – Tema 2.C Wireless LANs: the IEEE 802.11 standards
The 802 wireless family
IEEE
The physical layer
The MAC layer
Quality of service: e
MIMO: n
Management tools

57. Limitations of the MAC standard for QoS
DCF (Distributed Coordination Function)
Only support best-effort services
No guarantee in bandwidth, packet delay and jitter
Throughput degradation in the heavy load
PCF (Point Coordination Function)
Inefficient and complex central polling scheme
Unpredictable beacon frame delay due to incompatible cooperation between CP and CFP modes
Transmission time of the polled stations is unknown

58. Overview of e
Task group e formed in Sep and Approved in July 2005
Current version: IEEE P802.11e/D13.0
Backwardly compatible with the DCF and PCF
New QoS mechanism: HCF (Hybrid Coordination Function)
Contention-based channel access
EDCA (Enhanced Distributed Channel Access)
was Enhanced Distributed Coordination Function (EDCF)
Controlled channel access (includes polling)
HCCA (HCF controlled channel access)
The station that operates as the central coordinator for all other stations within the same QoS supporting BSS (QBSS) is called the hybrid coordinator (HC).
The HC reside inside an AP
A BSS that includes an e-compliant HC is referred to as a QBSS.

59. EDCA parameters for AC 4 access categories (AC),
AIFS[AC] = SIFS + AIFSN[AC] * aSlotTime, AIFSN[AC]  2.

60. EDCA and AC Mapping

61. HCF: Hybrid Coordination Function
During CFP
Poll STAs and give a station the permission to access channel
Starting time and maximum duration of each TXOP are specified by the HC
During CP
Can use the EDCA rules
HC can issue polled TXOPs in the CP by sending CF-Poll after a PIFS idle period
Controlled Contention
Allows STAs to request the allocation of polled TXOPs
STAs send resource request frames with the requested TC and TXOP duration
HC sends an ACK for resource request to the STA

62. HCF superframes

63. Performance

64. QoS: 802.11e and WMM™ WMM (Wi-Fi Multimedia)
Prioritized QoS subset of e draft
Widely accepted by e members
Added to Wi-Fi certification in September 2004

65. WMM™ for Video
Source: Wi-Fi Alliance

66. Redes Inalámbricas – Tema 2.C Wireless LANs: the IEEE 802.11 standards
The 802 wireless family
IEEE
The physical layer
The MAC layer
Quality of service: e
MIMO: n
Management tools
Thanks to: Paul Young / Bernie Rasenberger

67. What is “Wireless N”?
802.11n is the long anticipated update to Wi-Fi standards.
Ratified by IEEE in September 2009.
“Pre-N” wireless devices were available prior to ratification (Draft N) with speeds of up to 300Mb/s and range of up to 300 metres (300x300).
Increases channel utilisation through MAC aggregation (40MHz) and increased range & throughput through the use of MIMO (Multiple Input/Multiple Output) technology of 2+ antennas.
Will co-exist with b/g networks, but can degrade them because of channel overlap caused by MAC aggregation.
Same performance hit if you mix n clients with b clients, as you get with mixing g & b clients (OFDM).

68. What is “Wireless N”? 802.11n Release Date November 2009 Speed
300 Mbps
Throughput
74 Mbps
Frequency
2.4GHz &/or 5.0GHz
Range (outdoor)
250 meters
802.11n’s improved technology
802.11n’s version of OFDM: a/g already uses OFDM (Orthogonal Frequency-Division Multiplexing) to achieve data rates of 54 Mbps n OFDM technology builds on a/g OFDM modulation by creating support for multiple channels (MIMO), allowing more bandwidth per channel, and higher code rates. This brings the maximum data rate of a single n OFDM channel to 65 Mbps.
MIMO antenna systems: The n standard allows up to 4 MIMO transmit/receive antenna pairings n OFDM has a maximum data rate of 65 Mbps, multiplying that by the 4 MIMO antenna channels raises the data rate to 260 Mbps, which is a significant improvement when compared to 54 Mbps.
40 MHz channels: To further improve data rates, n allows the use of 40 MHz channels-twice the existing 20MHz channels used by a/b/g-which effectively doubles the data rate to over 500 Mbps. 40 MHz channel size is also the most controversial tenet of the new standard, having the potential to disrupt existing a/b/g networks due to co-channel interference.
Aggregation: Aggregation is an important feature developed to overcome shortcomings of having to be backward compatible with a/b/g networks. It improves mixed-mode performance and efficiency by bundling several frames together that are destined for n devices, while still being able to transmit single data frames to legacy devices.
RIFS (Reduced Inter-Frame Spacing): RIFS is a required n feature that also improves performance by reducing the amount of dead time required between OFDM transmissions. It should be noted that this feature is restricted to greenfield deployments.

69. Why is it so fast? Spatial multiplexing
With spatial multiplexing, the stream of data is split between 2 antennae and reassembled at the receiver. More data goes through in the same amount of time than when using a single antenna.

70. Why is it so fast? Support for 40Mhz Channels
So far each b/g channel only used 20MHz of the spectrum. With more spectrum available, more data can go through.

71. Wireless N is also more reliable
Through the use of Multipath we can achieve a more robust signal
Antennas cleverly combine the same signal which has travelled through different paths. Even if the environment changes and some of the signal is obstructed, enough can still go through.
This is how Wireless N achieves A ROBUST SIGNAL, less prone to interference and environmental changes.
Resulting signal
Transmitter
Receiver
Multiple copies of signal received
Adjusted and combined signals

72. Deployment Considerations
802.11n can operate on 2.4 GHz or/and 5 GHz and is backward compatible with a/b/g. Access Points can be set to support 11n only.
AP’s can be:
single radio (2.4GHz only or 5GHz only)
switchable dual radio (switchable between 2.4GHz and 5GHz)
concurrent dual radio (operates 2.4GHz and 5GHz at the same time)

73. Deployment Considerations
When introducing n into existing a/b/g WLANs both bands (2.4GHZ and 5GHz) can have n enabled.
In case of dense AP architecture channel bonding for 2.4GHz should be disabled (set to 20MHz).
Or if there are other 2.4GHz networks in the area – disable channel bonding for 2.4GHz.
802.11n can be offered to throughput-critical clients only which support 11n: 5GHz band can be set as “11n only”. Leaving 2.4GHz for the rest of the clients which will not interfere with the critical data (802.11b/g/n).
dual-radio n AP
2.4GHz
802.11b/g/n
5GHz
802.11n only
High Speed Wi-Fi
Legacy mixed Wi-Fi
802.11n client

74. The ‘Sting’
Increased channel spectrum from 22Mhz to 40Mhz, using MAC aggregation techniques;
Consumes 2 of 3 non overlapping 2.4Ghz channels;
Not an issue in “pure N” networks, but will cause issues in hybrid networks;
Uses OFDM, so if b clients on network performance degrades for all users.

75. Redes Inalámbricas – Tema 2.C Wireless LANs: the IEEE 802.11 standards
The 802 wireless family
IEEE
The physical layer
The MAC layer
Quality of service: e
MIMO: n
Management tools

76. Wireshark / Ethereal
Wireshark is the world's foremost network protocol analyzer, and is the de facto (and often de jure) standard across many industries and educational institutions.
Wireshark development thrives thanks to the contributions of networking experts across the globe. It is the continuation of a project that started in 1998.

77. Wireshark Features
Deep inspection of hundreds of protocols, with more being added all the time
Live capture and offline analysis
Standard three-pane packet browser
Multi-platform: Runs on Windows, Linux, OS X, Solaris, FreeBSD, NetBSD, and many others
Captured network data can be browsed via a GUI, or via the TTY-mode TShark utility
Rich VoIP analysis
Read/write many different capture file formats:
Capture files compressed with gzip can be decompressed on the fly
Live data can be read from Ethernet, IEEE , PPP/HDLC, ATM, Bluetooth, USB, Token Ring, Frame Relay, FDDI, and others
Decryption support for many protocols, including IPsec, ISAKMP, Kerberos, SNMPv3, SSL/TLS, WEP, and WPA/WPA2
Output can be exported to XML, PostScript®, CSV, or plain text

78. Wireshark / Ethereal

79. Kismet
Kismet is an layer2 wireless network detector, sniffer, and intrusion detection system. Kismet will work with any wireless card which supports raw monitoring (rfmon) mode, and can sniff b, a, and g traffic.
Kismet identifies networks by passively collecting packets and detecting standard named networks, detecting (and given time, decloaking) hidden networks, and infering the presence of nonbeaconing networks via data traffic.
Some of the features
Ethereal/Tcpdump compatible data logging
Built-in channel hopping and multicard split channel hopping
Hidden network SSID decloaking
Graphical mapping of networks
Manufacturer and model identification of access points and clients
Detection of known default access point configurations
Runtime decoding of WEP packets for known networks
Over 20 supported card types

80. gKismet

81. Network Stumbler
Allows to save and export data in several different formats
Supports GPS and the ability to store GPS information in conjunction with other data

82. Network Stumbler
The graphical interface used is very intuitive and allows various types of analysis in a simple and direct form

83. Network Stumbler