In this gist, we learn about Definition of Wifi , Architecture of Wifi and Advantages of wifi

WIFI.DOCX

Wi-Fi
(Wireless Fidelity) is a technology that allows electronic devices to connect to a local area network (LAN) wirelessly using radio waves. It is commonly used for internet access in homes, offices, and public spaces.
-Standard:
   Based on the IEEE 802.11 family of standards.
-Frequency Bands:
   Operates mainly on 2.4 GHz and 5 GHz bands; newer versions also use 6 GHz (Wi-Fi 6E).
-Range:
   Typically covers about 30 meters indoors; range can vary depending on interference and obstacles.
-Speed:
    Varies by version (e.g., Wi-Fi 4, 5, 6, and 6E); newer versions offer higher speeds and better performance.
-Security:
   Protected using encryption protocols like WPA2 and WPA3.
1. Devices (End-User Devices)
-Station (STA):
  This refers to any Wi-Fi enabled device, like a laptop, smartphone, tablet, etc. It connects wirelessly to the network.
oMobile Stations: Devices like smartphones, laptops, etc., that connect to an access point (AP).
-Fixed Stations: 
 Devices that are permanently installed, like desktop computers or printers.
2. Access Point (AP)
-The Access Point is a critical component that serves as a bridge between the wireless devices and the wired network (often the internet).
-It transmits and receives data wirelessly over radio waves.
-An AP connects directly to the wired network (router, switch, or hub), allowing the Wi-Fi devices (stations) to access resources like the internet.
3. Basic Service Set (BSS)
-The BSS is a fundamental building block of Wi-Fi networks. It's a group of devices that communicate with each other.
-There are two types of BSS:
-Infrastructure BSS: Where a group of devices communicates through an AP.
-Independent BSS (IBSS): Known as an ad-hoc network, where devices communicate directly without an AP.
4. Extended Service Set (ESS)
-An ESS is a network that includes multiple BSSs (each with its own AP). This allows for greater coverage and roaming capabilities.
-ESS is often used in larger networks, like campuses or large office buildings, where multiple APs are required for seamless coverage.
5. Service Set Identifier (SSID)
-SSID is a unique identifier for a Wi-Fi network. It helps devices find and join the appropriate network among multiple available networks.
-Each AP broadcasts the SSID of the network it supports. Devices use this to identify which network to connect to.
6. Wireless Distribution System (WDS)
-WDS allows the interconnection of multiple APs wirelessly, effectively expanding the range of the network without the need for a wired connection between APs.
-It helps in extending Wi-Fi coverage to larger areas like campuses or large homes.
7. Authentication Server
-Wi-Fi networks often require security protocols for encryption and authentication, such as WPA2 or WPA3.
-The Authentication Server (often integrated with the AP) is responsible for authenticating users and devices before granting access to the network.
-This could involve methods like passwords, certificates, or even more advanced protocols like RADIUS (Remote Authentication Dial-In User Service).
8. Router
-The router connects the Wi-Fi network to the external world, such as the internet or other wide-area networks (WANs).
-It routes the data between the AP (or APs) and the internet, allowing devices on the Wi-Fi network to access online resources.
9. Channels and Frequency Bands
-Wi-Fi operates in specific radio frequency bands, such as:
2.4 GHz: Common but more crowded with other devices (e.g., microwaves, Bluetooth devices).
5 GHz: Offers more channels and is less crowded, but has a shorter range.
-The use of channels (typically numbered 1-11 in the 2.4 GHz band) helps reduce interference between devices.
10. Radio Frequency (RF) Communication
-Wi-Fi relies on radio waves to transmit data. The AP and the devices communicate using the radio spectrum.
-Data is transmitted in packets over the radio frequencies, with modulation schemes like OFDM (Orthogonal Frequency-Division Multiplexing) to ensure efficient and reliable transmission.
11. Protocol Stack
-The Wi-Fi system operates over a layered protocol stack, similar to the OSI model:
Physical Layer (PHY): Defines how the wireless signal is transmitted and received.
Medium Access Control (MAC) Layer: Handles how data is framed and transmitted between devices. It ensures that multiple devices can communicate without interference.
Network Layer: Handles IP addressing and routing for devices in the Wi-Fi network.
Transport and Application Layers: Deal with the data being transmitted (e.g., HTTP, FTP).
12. Security and Encryption
-Wi-Fi networks use security protocols like WPA (Wi-Fi Protected Access) and WPA2/WPA3 to ensure secure communication.
-Encryption techniques, such as AES (Advanced Encryption Standard), help prevent unauthorized access to data.

Advantages of Wi-Fi
1.Wireless Connectivity:
oWi-Fi eliminates the need for physical cables, offering users freedom of movement and flexibility in connecting to the network from virtually anywhere within range of the access point.
2.Convenience:
oDevices like smartphones, laptops, tablets, and other mobile devices can connect to the network without being tethered to a specific location, making it ideal for homes, offices, and public spaces.
3.Easy Setup:
oSetting up a Wi-Fi network is relatively simple and requires minimal technical expertise. It typically involves connecting an access point or router and configuring the settings.
4.Cost-Effective:
oWireless networks can save money on cables, switches, and physical network infrastructure. They also allow easy scaling without the need to lay new cables.
5.Multi-Device Connectivity:
oA single Wi-Fi access point can support multiple devices simultaneously, making it suitable for environments like homes, offices, and cafes.
6.Mobility and Flexibility:
oWi-Fi allows users to move around within the coverage area without losing connectivity, enabling mobile work, collaboration, and convenience.
Disadvantages of Wi-Fi
1.Limited Range:
Wi-Fi signals typically have a limited range. Once you move out of the coverage area of the access point, the connection becomes weak or entirely lost.
2.Interference:
Wi-Fi networks can be affected by interference from other devices, such as microwaves, Bluetooth devices, or even other Wi-Fi networks using the same or overlapping channels.
3.Security Risks:
Without proper security protocols, Wi-Fi networks are vulnerable to unauthorized access. Even with encryption (WPA2/WPA3), there is always a risk of hacking or eavesdropping if the network is not properly configured.
4.Speed Limitations:
While Wi-Fi is generally fast, the speed can be significantly lower than wired connections (Ethernet). Speeds can be impacted by the distance from the AP, interference, or network congestion.
5.Potential for Congestion:
In areas with many Wi-Fi networks (e.g., apartment buildings), the wireless spectrum can become crowded, leading to slower speeds and connectivity issues due to high network traffic.
6.Power Consumption:
Wi-Fi-enabled devices often consume more battery power compared to wired connections, especially when the signal strength is weak, causing devices to use more energy to maintain the connection.
7.Security Challenges:
Setting up a secure Wi-Fi network requires attention to details such as proper password management, encryption standards, and regular software updates. Without these precautions, the network can be easily compromised.