3. References
• NPTEL Video Lecture :-
https://www.youtube.com/watch?v=6SWBxiPeSqk
• Textbook:- Wireless Communication and Networks,
William Stallings [UNIT-14]
• Website :-
https://in.mathworks.com/help/wlan/gs/what-is-
wlan.html
• https://www.spiceworks.com/tech/networking/articles/
wpa-wifi-protected-access/
4. Introduction
• 802.11 is a member of the IEEE 802 family,
which is a series of specifications for local area
network (LAN) technologies.
• IEEE 802 specifications are focused on the two
lowest layers of the OSI model because they
incorporate both physical and data link
component
5. Individual specifications in the 802 series are identified by a second number
Other specifications describe other parts of the 802 protocol stack. 802.2 specifies a
common link layer, the Logical Link Control (LLC), which can be used by any lower-layer
LAN technology. Management features for 802 networks are specified in 802.1. Among
802.1's many provisions are bridging (802.1d) and virtual LANs, or VLANs (802.1q).
7. Disadvantages of WLAN
•Quality of Services.
•Proprietary Solutions
•Restrictions
•Global operation
•Low Power
•License free operation
•Robust transmission technology
8.
9. Network Architecture
• 802.11 networks consist of four major physical
components, The components are:
- Distribution System
- Access Points
- Wireless Medium
- Stations
10. Terminology
• Distribution System:- When several access
points are connected to form a large coverage
area, they must communicate with each other
to track the movements of mobile stations.
• The distribution system is the logical
component of 802.11 used to forward frames
to their destination
11. Terminology
• Access points
Frames on an 802.11 network must b
converted to another type of frame for delivery
to the rest of the world. Devices called access
points perform the wireless-to-wired bridging
function
12. Terminology
• Stations
Networks are built to transfer data between
stations. Stations are computing devices with
wireless network interfaces. Typically, stations
are battery-operated laptop or handheld
computers
14. Infrastructure Networks
• Access points are used for communication
• The communication is carried out with two hops
• Advantages of using a AP
- There is no restriction on the distance between
mobile stations
- AP can help with power saving
15. Association
• stations must associate with an access point to
obtain network service
• Association is the process by which mobile
station joins an 802.11 network
• Associations are also exclusive on the part of the
mobile station: a mobile station can be associated
with only one access point.
16. Extended Service set (ESS)
• BSS cannot provide coverage for large areas
• 802.11 allows wireless networks of arbitrarily
large size to be created by linking BSSs into an
extended service set (ESS)
• An ESS is created by chaining BSSs together with
a backbone network.
• 802.11 does not specify a particular backbone
technology ( but usually Ethernet is used)
23. 802.11 b (WIFI 1)
• Released in 1999
• Technology used: DSSS
• Modulation Scheme: DQPSK
• Base Frequency: 2.4 GHz
• Bandwidth : 11 MHz
• Maximum Throughput : 11 Mbps
• Antenna Scheme : SISO
• PPDU Format: non-HT
24. 802.11 a (WIFI 2)
• Released in 1999
• Technology used: OFDM
• Modulation Scheme: BPSK, QPSK, 16 QAM, 64 QAM ( based
on data rate)
• Base Frequency: 5 GHz
• Bandwidth : 5,10,20 MHz
• Maximum Throughput : 54 Mbps
• Antenna Scheme : SISO
• PPDU Format: non-HT
25.
26. 802.11 g (WIFI 3)
• Released in 2003
• Modulation Scheme used: Multiple
• Base Frequency: 2.4 GHz
• Bandwidth : Multiple
• Maximum Throughput : 54 Mbps
• Antenna Scheme : SISO
• PPDU Format: non-HT
27.
28. 802.11 n (WIFI 4)
• Released in 2009
• Modulation Scheme used: OFDM
• Base Frequency: 2.4 GHz and 5GHz
• Bandwidth : 20,40 Mhz
• Maximum Throughput : < 600 Mbps
• Antenna Scheme : MIMO up to 4 streams
• PPDU Format: HT, non-HT, Duplicate
29. 802.11 n (WIFI 5)
• Released in 2013
• Modulation Scheme used: OFDM
• Base Frequency: 2.4 GHz and 5GHz
• Bandwidth : 20,40 Mhz
• Maximum Throughput : < 600 Mbps
• Antenna Scheme : MIMO up to 4 streams
• PPDU Format: HT, non-HT, Duplicate
30. 802.11 n (WIFI 6)
• Released in 2021
• Modulation Scheme used: OFDMA
• Base Frequency: 2.4 GHz, 5 GHz, 6 GHz ( WIFI 6E)
• Bandwidth : 20, 40, 80, 160, 80+80 MHz
• Maximum Throughput : < 10 Gbps
• Antenna Scheme : UL and DL MU-MIMO up to eight
streams
• PPDU Format: HE, non-HT duplicate
31. 802.11 be (WIFI 7)
• To be released in 2024 tentatively
• Modulation Scheme used: OFDMA
• Base Frequency: 2.4 GHz, 5 GHz, 6 GHz
• Bandwidth : 20, 40, 80, 160, 320 Mbps
• Maximum Throughput : < 40 Gbps
• Antenna Scheme : UL and DL MU-MIMO up to 16
streams
• PPDU Format: EHT
32.
33. Security
• The 802.11i task group has developed a set of capabilities to
address the WLAN security issues.
• In order to accelerate the introduction of strong security
into WLANs, the Wi-Fi Alliance promulgated Wi-Fi
Protected Access (WPA) as a Wi-Fi standard.
• WPA is a set of security mechanisms that eliminates most
802.11 security issues and was based on the current state of
the 802.11i standard.
• As 802.11i evolves, WPA will evolve to maintain
compatibility
34. FEATURES OF WPA
• WPA, is a network security standard mandatory for wireless
networks to protect them via authentication and encryption,
replacing the older Wired Equivalent Privacy (WEP) system.
• It was formally adopted in 2003
• WPA requires that users input a password for authentication to
ensure that the WiFi networks are protected.
• It supports authentication servers or remote authentication dial-in
(RADIUS) servers. Additionally, it also encrypts data better than
WEP.
• WPA was designed to be backward-compatible and doesn’t require
upgrading the hardware.
• Users can add WPA to the hardware through firmware upgrades.
• WPA uses TKIP protocol
35. FEATURES OF WPA
• Organizations can apply the WPA standard in one of two
modes, and they can use these modes in all three generations
of WPA:
WPA personal: It is also referred to as WPA pre-shared key
(WPA-PSK). It is designed for use on small or home networks
WPA enterprise: This mode is designed for medium or large
networks and is also known as WPA-802.1x. Its system is
more challenging to configure. Users must employ their
personal identities to join the network through a RADIUS
server ( remote authentication dial-in )
36. Essential Elements of WPA
• . Temporal Key Integrity Protocol (TKIP)
-TKIP employs a 128-bit shared temporary key between the
wireless user and access points (AP). It distributes new
temporary keys every 10,000 packets, enhancing the network’s
security. It ensures that the same key is not re-used to encrypt
data by frequently processing changes in the encryption keys.
• Advanced Encryption Standard (AES)
• Built-in authentication
• Four-way handshake
• Message Integrity Check (MIC)
37. • The 802.11i architecture consists of three main ingredients:
• Authentication: A protocol is used to define an exchange
between a user and an AS that provides mutual authentication and
generates temporary keys to be used between the client and the AP
over the wireless link.
• Access control: This function enforces the use of the
authentication function, routes the messages properly, and
facilitates key exchange. It can work with a variety of authentication
protocols.
• Privacy with message integrity: MAC-level data (e.g., an LLC
PDU) are encrypted, along with a message integrity code(MIC)
that ensures that the data have not been altered.
38.
39. Hotspots
• Hotspot: A hotspot is a physical location
where people can access the Internet,
typically using Wi-Fi, via a wireless local area
network (WLAN) with a router connected to
an Internet service provider.
40. Hotspots
• Mobile hotspot: A mobile hotspot (sometimes
called a portable hotspot) is a hotspot that’s just
that—mobile! While a “regular” Wi-Fi hotspot is
tied to a physical location, you can create a
mobile hotspot by using your Smartphone's data
connection to connect your laptop to the
Internet. This process is called “tethering.”
41. Security Issues with Public Wi-Fi Network
• Evil twin attack. Hackers set up malicious hotspots with seemingly trustworthy
names (e.g. “Cafe free Wi-Fi”). When you connect, they can easily intercept your
data.
• Man-in-the-middle attack (MitM). Bad actors break into a network and eavesdrop
on data as it travels between connected devices and the Wi-Fi router. For example,
as you enter your password into your online bank account.
• Password cracking attack. Scammers use software that automatically tries a huge
volume of usernames and passwords to unlock a router’s management interface.
• Packet sniffing attack. Malicious hackers capture data units sent across unsecured
Wi-Fi. Then, they unpack the data to extract individual login credentials or financial
information.
• Security vulnerabilities and/or misconfigurations. Sometimes default router settings
allow cybercriminals to log in as an administrator, or plant malicious software on
compromised devices.
42. Virtual Private Networks
• VPN stands for "Virtual Private Network" and
describes the opportunity to establish a protected
network connection when using public networks.
VPNs encrypt your internet traffic and disguise your
online identity.
• This makes it more difficult for third parties to track
your activities online and steal data. The encryption
takes place in real time.
43.
44. Virtual Private Networks
• A VPN is created by establishing a virtual point-to-
point connection through the use of tunneling
protocols over existing networks
• User can be part of a local network sitting at a remote
location. It makes use of tunneling protocols to
establish a secure connection
• VPN can be used to camouflage our geolocation.
45. How VPN works
• A VPN hides your IP address by letting the network redirect it
through a specially configured remote server run by a VPN host.
• This means that if you surf online with a VPN, the VPN server
becomes the source of your data.
• This means your Internet Service Provider (ISP) and other third
parties cannot see which websites you visit or what data you send
and receive online.
• A VPN works like a filter that turns all your data into "gibberish".
Even if someone were to get their hands on your data, it would be
useless.
46.
47. Advantages of VPN
• Secure Communication over insecure network
- Encryption of IP
-Encryption of protocols
-Two Factor Authentication
• Private address on top of public address
• Access regional content
48. HIPERLAN STANDARD
• Stands for High Performance Radio LAN
• It is European alternative for WLAN networks
• It is defined by the European Telecommunications Standards Institute (ETSI)
• The 4 Hiperlan standards are Hiperlan 1 , Hiperlan 2, HIPERACCESS,
HIPERLINK
• Due to competition from IEEE 802.11, which was simpler to implement and made
it faster to the market, HiperLAN never received much commercial
implementation.
• Much of the work on HiperLAN/2 has survived in the PHY specification for IEEE
802.11a, which is nearly identical to the PHY of HiperLAN/2.
• HIPERACCESS was intended as a last-mile technology.
• HIPERLINK was intended as a short-range point-to-point technology at 155 Mbit/s.
49. HiperLan Features
• HIPERLAN uses cellular-based data networks to connect to an
ATM backbone.
• The main idea behind HIPERLAN is to provide an
infrastructure or ad-hoc wireless with low mobility and a small
radius.
• HIPERLAN supports isochronous traffic with lo
• On the physical layer FSK and GMSK modulations are used in
HiperLAN
