2.3 & 2.4: Networking

802.11 Wireless Networking

Managed by IEEE LAN/MAN Standards Committee (IEEE 802); continuously updated; Wi-Fi trademark managed by Wi-Fi Alliance.

802.11a

One of the original wireless standards (1999); operates at 5 GHz; 54 Mbit/s; shorter range due to high frequency absorption; now obsolete.

802.11b

Original 2.4 GHz standard (1999); 11 Mbit/s; longer range than 802.11a but prone to interference from other 2.4 GHz devices; now obsolete.

802.11g

Upgrade to 802.11b (2003); 2.4 GHz, 54 Mbit/s; backward-compatible with 802.11b; suffers same interference issues.

802.11n (Wi-Fi 4)

Introduced in 2009; supports 2.4 GHz and/or 5 GHz; up to 600 Mbit/s; supports 40 MHz channels and MIMO (multiple input/output).

802.11ac (Wi-Fi 5)

Upgrade to 802.11n (2014); 5 GHz only; supports up to 160 MHz channels, dense modulation, and 8 MU-MIMO streams; up to 7 Gbit/s.

802.11ax (Wi-Fi 6)

Successor to Wi-Fi 5 (2021); supports 2.4 and 5 GHz; 20–160 MHz channel widths; up to 1201 Mbit/s per channel; uses OFDMA for high-density.

MIMO

Multiple Input, Multiple Output; allows multiple data streams on multiple antennas for improved throughput (802.11n and up).

MU-MIMO

Multi-User MIMO; allows simultaneous communication with multiple devices; introduced with 802.11ac and improved in 802.11ax.

OFDMA

Orthogonal Frequency-Division Multiple Access; subdivides channels for simultaneous communication with multiple users; used in Wi-Fi 6.

Long-Range Wireless Antennas

Used to connect buildings across long distances; requires directional antennas; outdoors = minimal absorption/bounce.

Directional Antennas

Focus wireless signal in a specific direction; ideal for point-to-point outdoor connections.

Wireless Regulations

Frequencies (2.4 & 5 GHz) typically unlicensed; higher power or other frequencies may require licensing.

RFID (Radio-Frequency Identification)

Uses radio energy to power and communicate with passive/active tags; used in inventory, pets, access cards, etc.

802.11 Frequencies

Wireless networks operate on 2.4 GHz and/or 5 GHz; each band includes multiple channels.

Wireless Channels

IEEE assigns frequency ranges into channels; non-overlapping channels reduce interference.

Wireless Regulations

Countries regulate frequency use, spectrum limits, power output, and interference compliance.DNS Server

DHCP Server

Dynamic Host Configuration Protocol; assigns IP addresses automatically; common in home routers; enterprise setups use redundant central servers.

File Server

Central storage for files (docs, videos, images); managed via SMB or AFP protocols; allows copying, deleting, renaming across a network.

Print Server

Connects printers to the network; can be built into printer or hosted by a computer; uses SMB, IPP, or LPD protocols for print jobs.

Mail Server

Manages sending and receiving of email; critical service managed by ISPs or IT; often requires 24/7 uptime.

Syslog

Standard for message logging; logs stored on centralized servers and integrated into SIEM; requires large storage capacity.

Web Server

Hosts websites; serves HTTP/HTTPS requests; delivers static or dynamically generated content to browsers.

Authentication Server

Centralized login service for user authentication; used in enterprises with redundant servers; vital for resource access control.

Spam

Unsolicited messages like ads or phishing; can impact security and storage; spam gateways filter messages before reaching the user.

All-in-One Security Appliance

Unified Threat Management (UTM); combines firewall, router, IDS/IPS, VPN, filtering, and malware protection into one device.

Load Balancer

Distributes traffic across multiple servers; provides fault tolerance and high availability; supports SSL offload, caching, QoS, and content switching.

Proxy Server

Acts as intermediary for client-server requests; supports access control, URL filtering, caching, and content scanning.

SCADA/ICS

Supervisory Control and Data Acquisition; used for large industrial systems like power and manufacturing; requires secure segmentation.

Legacy Systems

Outdated but critical systems still in use; may lack modern features but support important functions.

Embedded Systems

Purpose-built systems like door locks, alert systems; limited OS access; run dedicated tasks with high reliability.

IoT Devices

Networked appliances and smart devices (e.g., thermostats, doorbells); may require segmented networks for added security.