Wireless Concepts

A wireless network is a set of two or more devices connected with each other via radio waves within a limited space range. The devices in a wireless network have the freedom to be in motion, but be in connection with the network and share data with other devices in the network. One of the most crucial point that they are so spread is that their installation cost is very cheap and fast than the wire networks.

Wireless Terminologies

  • GSM: Universal system used for mobile transportation for wireless network worldwide.
  • Bandwidth: Describes the amount of information that may be broadcasted over a connection
  • BSSID: The MAC address of an access point that has set up a Basic Service Set (BSS).
  • ISM band: A set of frequency for the international Industrial, Scientific, and Medical communities.
  • Access Point: Used to connect wireless devices to a wireless network.
  • Hotspot: Places where wireless network is available for public use.
  • Association: The process of connecting a wireless device to an access point.
  • Orthogonal Frequency-division Multiplexing (OFDM): Method of encoding digital data on multiple carrier frequencies.
  • Direct-sequence Spread Spectrum (DSSS): Original data signal is multiplied with a pseudo random noise spreading code.
  • Frequency-hopping Spread Spectrum (FHSS): Method of transmitting radio signals by rapidly switching a carrier among many frequency channels. 

Wireless Network

  • Wi-Fi refers to wireless local area networks (WLAN) based on IEEE 802.11 standard.
  • It is a widely used technology for wireless communication across a radio channel.
  • Devices such as a personal computer, video-game console, smartphone, etc. use Wi-Fi to connect to a network resource such as the Internet via a wireless network access point.
  • Advantages:
    • Installation is fast and easy and eliminates wiring through walls and ceilings.
    • It is easier to provide connectivity in areas where it is difficult to lay cable.
    • Access to the network can be from anywhere within range of an access point.
    • Public places like airports, libraries, schools or even coffee shops offer you constant Internet connections using Wireless LAN.
  • Disadvantages:
    • Security is a big issue and may not meet expectations.
    • As the number of computers on the network increases, the bandwidth suffers.
    • Wi-Fi enhancements can require new wireless cards and/or access points.
    • Some electronic equipment can interfere with the Wi-Fi networks. 

Wi-Fi Networks at Home and Public Places 

  • Wi-Fi at Home: Wi-Fi networks at home allow you to be wherever you want with your laptop, iPad, or handheld device, and not have to make holes for or hide Ethernet cables.
  • Wi-Fi at Public Places: You can find free/paid Wi-Fi access available in coffee shops, shopping malls, bookstores, offices, airport terminals, schools, hotels, and other public places.

Wireless Technology Statistics

  • Why Wireless Technology Matters?
    • More than half of all open Wi-Fi networks are susceptible to abuse.
    • There will be more than 7 billion new Wi-Fi enabled devices in the next 3 years.
    • 71% of all mobile communications flows over Wi-Fi.
    • By 2017, 60% of carrier network traffic will be offloaded to Wi-Fi.
    • A Wi-Fi attack on an open network can take less than 2 seconds.
    • 90% of all smartphones are equipped with Wi-Fi capabilities.

Types of Wireless Networks 

1. Wireless LAN

Within a building or in a small outdoor area, internet connection is made possible through wireless LAN (WLAN) technology. WLAN technology was initially utilized in homes and businesses, but is now present in shops and dining establishments. Due to the COVID-19 pandemic forcing office workers, students, teachers, and others to work and study from home, the use of home networks has significantly expanded.

Most home network designs are simple. A modem connects to the cable or fiber from a local service provider. A wireless router is connected to the modem and receives the signal from the modem, which it then broadcasts using a wireless protocol, such as the 802.11 standards.

Office networks are more complicated. Access points (APs) are mounted on the ceiling, with each broadcasting a wireless signal to the surrounding area. Multiple APs are required in large offices, each connecting to the office backbone network via a wired connection to a switch.

2. Wireless MAN

Wireless metropolitan area networks have been installed in cities worldwide to provide access for people outside an office or home network. Although these networks have a larger coverage area than networks in offices or homes, the fundamentals are the same. All around the service region, APs can be seen on the sides of buildings or atop telephone poles. APs transmit a wireless signal throughout the region while being wired to the internet. Users connect to the closest AP, which then forwards the connection through its internet connection, to reach their intended destination.

3. Wireless PAN

Wireless personal area networks cover a very limited area — typically a maximum of 100 meters for most applications — using protocols like Bluetooth and Zigbee. Bluetooth enables hands-free phone calls, connects a phone to earpieces or transmits signals between smart devices. Zigbee connects stations along an IoT network. Infrared technology is limited to line of sight, such as connecting TV remotes to televisions.

Wireless developers have constantly improved technology by discovering new ways to transmit signals to users. These advances enable higher data rates and increasing range for each of these wireless technologies.

4. Wireless WAN

Wireless WANs use cellular technology to provide access outside the range of a wireless LAN or metropolitan network. These networks enable users to make phone calls to others connecting either through a wireless WAN or a wired telephone system. Users can also connect to the internet to access websites or server-based applications.

In the United States and the majority of other nations, cell towers can be found almost anywhere. Whenever a user connects, the connection is forwarded to the closest cell tower, which is then either connected to the wired internet or to another tower that is. 

Wireless Standards

Amendments Freq. (GHZ) Modulation Speed (Mbps) Range (ft)
802.11a 5 OFDM 54 25-75
802.11b 2.4 DSSS 11 150-150
802.11g 2.4 OFDM, DSSS 54 150-150
802.11i Defines WPA2-Enterprise/WPA2-Personal for Wi-Fi
802.11n 2.4, 5 OFDM 54 ~100
802.16 (WiMAX) 10-66 70-1000 30 miles
Bluetooth 1:8 1-3 25

Service Set Identifier (SSID)

  • SSID is a token to identify a 802.11 (Wi-Fi) network; by default it is the part of the frame header sent over a wireless local area network (WLAN).
  • It acts as a single shared identifier between the access points and clients.
  • Access points contunuously broadcasts SSID, if enabled, for the client machines to identify the presence of wireless network.
  • SSID is a human-readable text string with a maximum length of 32 bytes.
  • If SSID of the network is changed, reconfiguration of the SSID on every host is required, as every user of the network configures the SSID into their system.
  • A non-secure access mode allows clients to connect to the access point using the configured SSID, a blank SSID, or an SSID configured as “any”.
  • Security concerns arise when the default values are not changed, as these units can be compromised.
  • The SSID remains secret only on the closed networks with no activity, that is inconvenient to the legitimate users.

Wi-Fi Authentication Modes

It is important to understand that there is a distinction between being authenticated onto a wireless network and then having the traffic passed be encrypted. It is possible to be authenticated onto a network and pass open unencrypted traffic; this section looks at the commonly used methods of authentication.

There are three main methods of authentication that are used on today’s wireless LANs:

  • open authentication
  • shared authentication
  • EAP (Extensible Authentication Protocol) authentication

The open authentication method is the simplest of the methods used and only requires that the end device be aware of the Service-Set Identifier (SSID) used on the network, as long as the SSID is known then the device will be allowed onto the network. The problem with this method is that the SSID is typically broadcast and if it is not, it can be easy to figure out with passive capturing techniques.

The shared authentication method is commonly used on individual and small business wireless LAN implementations; this method uses a shared key (Pre-Shared Key – PSK) that is given to both sides of the connection; if they match then the device is allowed onto the network.

The third method uses the Extensible Authentication Protocol (EAP) and is the most common method used by enterprises. The EAP method utilizes an authentication server that is queried for authentication using a variety of credential options. 

Wi-Fi Authentication Process Using a Centralized Authentication Server

Wi-Fi Chalking 

Warchalking occurs when people draw symbols in areas to indicate the presence of an open Wi-Fi network. The symbols used typically say something about the access point. At its height, warchalking attracted hackers to break into the said public Wi-Fi networks and gather information about their users.

  • WarWalking: Attackers walk around with Wi-Fi enabled laptops to detect open wireless networks.
  • WarChalking: A method used to draw symbols in public places to advertise open Wi-Fi networks.
  • WarFlying: In this technique, attackers use drones to detect open wireless networks.
  • WarDriving: Attackers drive around with Wi-Fi enabled laptops to detect open wireless networks.

Types of Wireless Antennas

  • Directional Antenna: Used to broadcast and obtain radio waves from a single direction.
  • Omnidirectional Antenna: It provides a 360 degree horizontal radiation pattern. It is used in wireless base stations.
  • Parabolic Grid Antenna: It is based on the principle of a satellite dish but it does not have a solid backing. They can pick up Wi-Fi signals ten miles or more.
  • Yagi Antenna: Yagi is a unidirectional antenna commonly used in communications for a frequency band of 10 MHz to VHF and UHF.
  • Dipole Antenna: Bidirectional antenna, used to support client connections rather than site-to-site applications.

Parabolic Grid Antenna

  • Parabolic grid antennas enable attackers to get better signal quality resulting in more data to eavesdrop on, more bandwidth to abuse and higher power output that is essential in Layer 1 DoS and man-in-the-middle attacks.
  • Grid parabolic antennas can pick up Wi-Fi signals from a distance of ten miles.

ee

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *