Wireless Networking

Overview

Wireless networking uses radio frequency (RF) signals to provide network connectivity without physical cables. Modern WiFi networks are essential for homes, offices, and public spaces, supporting laptops, smartphones, tablets, IoT devices, and more.

Prerequisites

Before diving into wireless networking, you should understand:

Network Fundamentals - Basic networking concepts
VLANs - Network segmentation (for SSID-to-VLAN mapping)
DHCP and DNS - Network services

802.11 Standards

WiFi is based on the IEEE 802.11 family of standards:

Standard	Name	Year	Frequency	Max Speed	Range	Notes
802.11b		1999	2.4 GHz	11 Mbps	Good	Obsolete
802.11a		1999	5 GHz	54 Mbps	Moderate	Obsolete
802.11g		2003	2.4 GHz	54 Mbps	Good	Legacy
802.11n	Wi-Fi 4	2009	2.4/5 GHz	600 Mbps	Good	Common
802.11ac	Wi-Fi 5	2014	5 GHz	3.5 Gbps	Good	Current standard
802.11ax	Wi-Fi 6	2019	2.4/5 GHz	9.6 Gbps	Better	Modern
802.11ax	Wi-Fi 6E	2020	6 GHz	9.6 Gbps	Good	Latest, requires new devices
802.11be	Wi-Fi 7	2024	2.4/5/6 GHz	46 Gbps	Better	Emerging

WiFi Generations Comparison

flowchart LR
    subgraph Legacy
        B[802.11b<br>11 Mbps<br>2.4 GHz]
        G[802.11g<br>54 Mbps<br>2.4 GHz]
    end
    
    subgraph Current
        N[WiFi 4<br>802.11n<br>600 Mbps<br>2.4/5 GHz]
        AC[WiFi 5<br>802.11ac<br>3.5 Gbps<br>5 GHz]
    end
    
    subgraph Modern
        AX[WiFi 6<br>802.11ax<br>9.6 Gbps<br>2.4/5 GHz]
        AXE[WiFi 6E<br>802.11ax<br>9.6 Gbps<br>6 GHz]
        BE[WiFi 7<br>802.11be<br>46 Gbps<br>2.4/5/6 GHz]
    end
    
    B --> G --> N --> AC --> AX --> AXE --> BE
    
    classDef legacy fill:#f9d5e5,stroke:#333
    classDef current fill:#d6e5fa,stroke:#333
    classDef modern fill:#c6d7eb,stroke:#333
    
    class B,G legacy
    class N,AC current
    class AX,AXE,BE modern

Key Improvements by Generation

WiFi 4 (802.11n):

MIMO (Multiple Input Multiple Output) - Multiple antennas
Channel bonding (20 MHz → 40 MHz)
Both 2.4 GHz and 5 GHz support

WiFi 5 (802.11ac):

Wider channels (80 MHz, 160 MHz)
MU-MIMO (Multi-User MIMO) - Serve multiple clients simultaneously
5 GHz only (cleaner spectrum)
Beamforming (directional signal focus)

WiFi 6 (802.11ax):

OFDMA (Orthogonal Frequency Division Multiple Access) - Efficient spectrum use
Target Wake Time (TWT) - IoT battery savings
1024-QAM modulation - More data per transmission
Better performance in crowded environments

WiFi 6E:

6 GHz band (1200 MHz of spectrum)
No legacy device interference
14 additional 80 MHz channels or 7 additional 160 MHz channels

WiFi 7 (802.11be):

320 MHz channels
Multi-Link Operation (MLO) - Simultaneous multi-band
4K-QAM modulation
Improved latency for gaming/VR

Frequency Bands

2.4 GHz Band

Characteristics:

Range: Excellent (penetrates walls better)
Speed: Lower (more interference)
Channels: 11 channels (North America), only 3 non-overlapping (1, 6, 11)
Interference: High (Bluetooth, microwaves, cordless phones, baby monitors)

Best For:

IoT devices (smart home, sensors)
Devices far from access point
Devices requiring wall penetration
Legacy device support

5 GHz Band

Characteristics:

Range: Moderate (less wall penetration)
Speed: Higher (less interference)
Channels: 24 non-overlapping channels (UNII-1, UNII-2, UNII-3)
Interference: Low (less crowded)
DFS: Dynamic Frequency Selection (shares with radar, may cause brief interruptions)

Best For:

Laptops, tablets, smartphones
Streaming video (Netflix, YouTube)
Video conferencing
Gaming
High-density environments

6 GHz Band (WiFi 6E)

Characteristics:

Range: Similar to 5 GHz
Speed: Highest (pristine spectrum)
Channels: 59 channels (14x 80 MHz, 7x 160 MHz, 3x 320 MHz)
Interference: None (new spectrum)
Compatibility: Requires WiFi 6E devices (iPhone 15+, recent Android flagships)

Best For:

VR/AR applications
4K/8K video streaming
Enterprise density scenarios
Future-proofing

WiFi Channels

2.4 GHz Channel Layout

Channel:  1   2   3   4   5   6   7   8   9   10  11
Freq:   2412 ...                 ...                2462 MHz
        
Non-overlapping:
         [====1====]  [=======6=======]  [====11====]
         
Overlapping (BAD):
         [====1====]
             [====3====]
                 [====5====]   ← INTERFERENCE!

Best Practice: Only use channels 1, 6, and 11 in 2.4 GHz

5 GHz Channel Layout

Many more non-overlapping channels available:

UNII-1 (Indoor):

Channels: 36, 40, 44, 48
Power: Lower
No DFS required

UNII-2A (Indoor):

Channels: 52, 56, 60, 64
DFS required (Dynamic Frequency Selection)
Shares with weather radar

UNII-2C (Indoor/Outdoor):

Channels: 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144
DFS required
Higher power allowed

UNII-3 (Outdoor):

Channels: 149, 153, 157, 161, 165
Higher power
No DFS required
Best for outdoor APs

Channel Width

Width	Use Case	2.4 GHz	5 GHz	6 GHz
20 MHz	Maximum compatibility, range	Standard	Available	Available
40 MHz	Balance speed/compatibility	Avoid (interference)	Good	Good
80 MHz	High performance	N/A	Best	Best
160 MHz	Maximum speed	N/A	Limited availability	Good
320 MHz	WiFi 7	N/A	N/A	WiFi 7 only

Recommendations:

2.4 GHz: Always 20 MHz (avoid 40 MHz, causes interference)
5 GHz: 80 MHz for most deployments, 40 MHz if crowded
6 GHz: 80-160 MHz depending on client support

WiFi Security

Security Protocols Evolution

Protocol	Year	Security	Status	Use
Open	N/A	None	Insecure	Never (except captive portal)
WEP	1999	Weak	Broken	Never use
WPA	2003	TKIP	Deprecated	Never use
WPA2-Personal	2004	AES-CCMP	Good	Home networks
WPA2-Enterprise	2004	AES-CCMP + 802.1X	Excellent	Corporate networks
WPA3-Personal	2018	SAE (Dragonfly)	Best	Modern home
WPA3-Enterprise	2018	192-bit	Best	Government, financial

WPA2-Personal (Pre-Shared Key)

How it works:

Single passphrase shared by all users
8-63 characters (longer = stronger)
AES encryption (CCMP mode)

Configuration:

SSID: MySecureNetwork
Security: WPA2-Personal
Passphrase: Sup3rS3cur3P@ssw0rdW1thL3ng7h!

Best Practices:

Minimum 20 characters for passphrase
Mix upper, lower, numbers, symbols
Avoid dictionary words
Change periodically (annually)
Never share publicly

Use Cases:

Home networks
Small offices (<10 people)
Guest networks (separate SSID)

WPA3-Personal (Enhanced)

Improvements over WPA2:

SAE (Simultaneous Authentication of Equals) - Stronger key exchange
Forward Secrecy - Past traffic remains secure even if passphrase compromised
Protection against brute force - Offline dictionary attacks prevented
Easier setup - WiFi Easy Connect (QR code)

Requirements:

WPA3-capable access points
WPA3-capable clients (most devices 2020+)

Transition Mode:

Security: WPA2/WPA3-Personal (Transitional)

Allows both WPA2 and WPA3 clients during migration.

WPA2/WPA3-Enterprise (802.1X)

How it works:

RADIUS server authenticates users
Unique credentials per user (username/password or certificate)
Centralized authentication and logging
Per-user/device policies

Components:

Client (Supplicant) ← → Access Point (Authenticator) ← → RADIUS Server

Authentication Methods:

PEAP-MSCHAPv2: Username/password (most common)
EAP-TLS: Certificate-based (most secure)
EAP-TTLS: Certificate + inner authentication

Advantages:

Individual user credentials
Audit logging (who connected when)
Easy user revocation
No shared passphrase
Dynamic VLAN assignment

Use Cases:

Corporate networks
Universities/schools
Healthcare
Any organization >50 users

WiFi Security Best Practices

Always use WPA2/WPA3 - Never open, WEP, or WPA
Strong passphrases - 20+ characters for WPA2-Personal
Separate guest network - Isolated from corporate
Hide SSID (optional) - Minimal security benefit, but reduces casual discovery
MAC filtering (optional) - Easy to bypass, not primary security
Enterprise for corporate - WPA2/WPA3-Enterprise with RADIUS
Regular firmware updates - Security patches
Disable WPS - Vulnerable to brute force attacks
Monitor rogue APs - Detect unauthorized access points

WiFi Network Design

Site Survey

Before deploying WiFi, conduct a site survey:

Goals:

Identify coverage gaps
Measure interference
Determine AP placement
Optimize channel assignment

Tools:

Ekahau Site Survey (professional)
NetSpot (affordable)
WiFi Analyzer (Android, free)
iStumbler (Mac, free)

Process:

Create floor plan
Measure signal strength throughout
Identify dead zones
Note interference sources
Plan AP locations

Access Point Placement

Guidelines:

Height:

Ceiling mount: 8-12 feet (2.5-3.5 m) ideal
Wall mount: 6-8 feet (2-2.5 m)

Coverage:

Indoor: 30-50 meters (100-165 feet) typical range
Walls: Reduce coverage significantly
Overlap: 15-20% overlap between APs for roaming

Density:

Office: 1 AP per 2,000-3,000 sq ft (185-280 sq m)
High density (conference room): 1 AP per 1,000 sq ft (93 sq m)
Outdoor: 1 AP per 10,000 sq ft (930 sq m)

Avoid:

Metal objects (filing cabinets, HVAC)
Microwaves, refrigerators
Thick concrete walls
Aquariums (water absorbs 2.4 GHz)

Channel Planning

Single AP Deployment

2.4 GHz: Channel 1 or 6 or 11 (least interference)
5 GHz: Auto (DFS channels OK) or manually select uncongested channel

Multiple AP Deployment

AP1: 2.4 GHz Channel 1, 5 GHz Channel 36
AP2: 2.4 GHz Channel 6, 5 GHz Channel 48
AP3: 2.4 GHz Channel 11, 5 GHz Channel 157

Repeat pattern for more APs, ensuring adjacent APs use different channels.

SSID Design

Single SSID (Recommended for most):

Corporate-WiFi (5 GHz and 2.4 GHz)

Advantages:

Simpler for users
Band steering (AP pushes capable devices to 5 GHz)
Seamless roaming

Multiple SSIDs (Advanced):

Corporate-5G (5 GHz only)
Corporate-2.4G (2.4 GHz only)
Corporate-Guest (Guest VLAN)
Corporate-IoT (IoT VLAN, limited access)

Advantages:

Explicit band selection
VLAN separation
Different security policies

Best Practice:

1-3 SSIDs per AP (performance impact beyond 4-5)
Corporate, Guest, and optionally IoT

WiFi Performance Optimization

Band Steering

Pushes dual-band clients to 5 GHz:

Methods:

Lower 2.4 GHz power
Delay 2.4 GHz probe responses
Active client steering

Benefits:

Frees 2.4 GHz for legacy/IoT devices
Better performance for capable clients
Reduced congestion

Roaming

Clients transition between APs seamlessly:

802.11r (Fast Roaming):

Pre-authenticates with neighboring APs
Reduces handoff time from 50ms to <10ms
Critical for VoIP, video calls

802.11k (Neighbor Reports):

APs report nearby APs to clients
Client can proactively roam to better AP

802.11v (BSS Transition Management):

AP suggests client roam to better AP
Disassociates sticky clients from weak signal AP

Best Practice: Enable 802.11r/k/v on enterprise APs

Airtime Fairness

Prevents slow clients from consuming disproportionate airtime:

Problem: 11 Mbps client takes 5x longer to transmit same data as 54 Mbps client

Solution:

Limit per-client airtime
Prioritize faster clients
Minimum RSSI requirements (disconnect weak clients)

Quality of Service (QoS)

Prioritize traffic types:

Priority	WMM Access Category	Traffic Type
Highest	Voice	VoIP, video conferencing
High	Video	Streaming, real-time video
Medium	Best Effort	Web browsing, downloads
Low	Background	File transfers, backups

Enable WMM (WiFi Multimedia) on all APs for QoS support.

Wireless Troubleshooting

Common Issues

Slow WiFi Speeds

Possible Causes:

Weak signal - Too far from AP, obstacles
Interference - Neighboring networks, 2.4 GHz devices
Client limitations - Old WiFi adapter (802.11g vs 802.11ac)
Channel congestion - Too many APs on same channel
ISP bottleneck - Slow internet (not WiFi problem)

Solutions:

Move closer to AP
Change channel (1, 6, or 11 for 2.4 GHz)
Switch to 5 GHz
Upgrade client WiFi adapter
Add more APs for coverage
Test wired speed to isolate WiFi vs internet

Can't Connect to WiFi

Checklist:

Correct passphrase
Compatible security protocol (WPA2 support)
DHCP scope not exhausted
MAC filtering not blocking device
Client driver updated
AP broadcasting SSID (if hidden, manually add)

Intermittent Disconnections

Causes:

Roaming issues (poor coverage overlap)
Interference
DFS channel radar detection (5 GHz)
Power management (client going to sleep)

Solutions:

Improve AP overlap for roaming
Change to non-DFS channels (149-165)
Disable aggressive power management
Update AP firmware

WiFi Analysis Tools

Windows

# View available networks
netsh wlan show networks mode=bssid

# View current connection
netsh wlan show interfaces

# Generate WiFi report
netsh wlan show wlanreport

Linux

# View networks
iwlist wlan0 scan

# Connection info
iwconfig wlan0

# Connection strength
watch -n 1 cat /proc/net/wireless

# Detailed info
iw dev wlan0 station dump

Mac

# Hold Option, click WiFi icon for detailed info
# Or:
/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I

# Scan networks
/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -s

Mobile Apps

WiFi Analyzer (Android) - Channel analysis, signal strength
NetSpot (Windows/Mac) - Site surveys, heatmaps
iStumbler (Mac) - Network discovery, signal monitoring

Signal Strength Interpretation

RSSI (dBm)	Signal Quality	Experience
-30 to -50	Excellent	Maximum performance
-50 to -60	Very Good	Reliable connectivity
-60 to -67	Good	Acceptable performance
-67 to -70	Fair	Minimum for VoIP
-70 to -80	Poor	Slow speeds, drops
-80 to -90	Very Poor	Unreliable
Below -90	No Signal	Cannot connect

Minimum Requirements:

Data browsing: -70 dBm
VoIP/streaming: -67 dBm
HD video: -60 dBm

Platform-Specific Implementation

UniFi WiFi

For Ubiquiti UniFi-specific configuration:

UniFi Network Guide

Enterprise WiFi

Consider enterprise solutions:

Cisco Meraki - Cloud-managed, easy, expensive
Aruba - Enterprise-grade, flexible
Ruckus - High performance, education/healthcare
Ubiquiti UniFi - Affordable, prosumer/SMB
Extreme Networks - Large scale, hospitals/warehouses

Best Practices Summary

Security

✅ WPA2/WPA3-Personal minimum (home)
✅ WPA2/WPA3-Enterprise (corporate)
✅ Separate guest network (isolated VLAN)
✅ Strong passphrases (20+ characters)
✅ Disable WPS
✅ Regular firmware updates

Performance

✅ Use 5 GHz for high-speed clients
✅ Reserve 2.4 GHz for IoT/legacy
✅ Non-overlapping channels (1, 6, 11 in 2.4 GHz)
✅ Enable 802.11r/k/v for roaming
✅ Band steering to 5 GHz
✅ Limit SSIDs (max 3-4 per AP)

Coverage

✅ Conduct site survey before deployment
✅ 15-20% AP overlap for roaming
✅ Ceiling mount 8-12 feet high
✅ Avoid metal, microwaves, thick walls

Management

✅ Centralized WiFi controller (enterprise)
✅ Monitor client connections and performance
✅ Regular channel analysis (interference)
✅ Document AP locations and channels

VLANs - SSID-to-VLAN mapping for network segmentation
Network Security - Advanced security frameworks
UniFi Equipment - Ubiquiti wireless implementation
DHCP - IP address management for wireless clients
Troubleshooting - Wireless diagnostics

Next Steps

After understanding wireless networking:

Conduct site survey for your environment
Plan VLAN strategy for SSID isolation
Configure guest network with limited access
Implement monitoring for WiFi health
Explore enterprise WiFi controllers

Additional Resources

WiFi Standards: IEEE 802.11 Working Group (https://www.ieee802.org/11/)
WiFi Alliance: https://www.wi-fi.org (certification, specs)
FCC Spectrum: https://www.fcc.gov/wireless-spectrum
Ekahau Blog: https://www.ekahau.com/blog (WiFi design)
Revolution WiFi: https://www.revolutionwifi.net (troubleshooting)

Wireless networking requires careful planning and ongoing optimization. Proper design ensures reliable, secure, high-performance WiFi for all users.

Table of Contents

Wireless Networking

Overview

Prerequisites

802.11 Standards

WiFi Generations Comparison

Key Improvements by Generation

Frequency Bands

2.4 GHz Band

5 GHz Band

6 GHz Band (WiFi 6E)

WiFi Channels

2.4 GHz Channel Layout

5 GHz Channel Layout

Channel Width

WiFi Security

Security Protocols Evolution

WPA2-Personal (Pre-Shared Key)

WPA3-Personal (Enhanced)

WPA2/WPA3-Enterprise (802.1X)

WiFi Security Best Practices

WiFi Network Design

Site Survey

Access Point Placement

Channel Planning

Single AP Deployment

Multiple AP Deployment

SSID Design

WiFi Performance Optimization

Band Steering

Roaming

Airtime Fairness

Quality of Service (QoS)

Wireless Troubleshooting

Common Issues

Slow WiFi Speeds

Can't Connect to WiFi

Intermittent Disconnections

WiFi Analysis Tools

Windows

Linux

Mac

Mobile Apps

Signal Strength Interpretation

Platform-Specific Implementation

UniFi WiFi

Enterprise WiFi

Best Practices Summary

Security

Performance

Coverage

Management

Related Topics

Next Steps

Additional Resources