Common WiFi Issues

Signal strength issues - Weak signal due to distance, obstacles, or interference
- RSSI (Received Signal Strength Indicator) should be -67 dBm or higher for good performance
- Physical barriers (walls, metal objects) can reduce signal by 10-20 dB per obstacle
- For example, 5 GHz signals have shorter range but less congestion than 2.4 GHz
Channel interference - Multiple networks operating on overlapping channels
- 2.4 GHz has only 3 non-overlapping channels (1, 6, 11) in North America
- 5 GHz offers 23+ non-overlapping channels with 80 MHz channel bonding
- Use WiFi analyzer tools to identify least congested channels
Authentication and association failures - Client cannot connect to access point
- Pre-shared key (PSK) mismatches in WPA2/WPA3 networks
- MAC address filtering blocking legitimate clients
- Maximum client limits reached on access point (typically 50-255 clients)
DHCP exhaustion - No available IP addresses for new clients
- Default residential router pools often limited to 50-100 addresses
- Lease time too long causing address starvation
- Rogue DHCP servers causing IP conflicts

Step	Action	Tools/Commands	Expected Result
1	Check physical layer	WiFi analyzer, signal meter	RSSI > -67 dBm, SNR > 20 dB
2	Verify authentication	Access point logs	Successful 4-way handshake
3	Confirm IP assignment	`ipconfig /all`, `ip addr show`	Valid IP in correct subnet
4	Test connectivity	`ping`, `traceroute`	Successful Layer 3 communication
5	Check DNS resolution	`nslookup`, `dig`	Proper name resolution

Spectrum analysis - Identify non-WiFi interference sources
- Microwave ovens, Bluetooth devices, baby monitors operate in 2.4 GHz ISM band
- Co-channel interference vs adjacent channel interference require different solutions
- Use 40/80/160 MHz channel bonding carefully to avoid overlap
Roaming issues - Clients not switching between access points optimally
- 802.11k/v/r standards enable fast roaming and band steering
- Client sticky behavior (remaining connected to distant AP with weak signal)
- Inconsistent SSID configuration across multiple access points
Capacity planning problems - Network cannot handle client density
- Each 802.11n stream provides ~150 Mbps theoretical, 802.11ac up to 867 Mbps per stream
- Airtime fairness ensures slower clients don’t monopolize channel time
- Plan for 20-25 concurrent clients per access point in high-density environments

RSSI - Received Signal Strength Indicator, measured in dBm (decibels relative to milliwatt)
SNR - Signal-to-Noise Ratio, difference between signal and background noise
BSS - Basic Service Set, single access point and its associated clients
ESS - Extended Service Set, multiple access points sharing same SSID
Airtime - Percentage of time channel is occupied by transmissions
Band steering - Directing dual-band clients to less congested 5 GHz band

Standard	Frequency	Max Speed	Range	Key Features
802.11n	2.4/5 GHz	600 Mbps	70m indoor	MIMO, 40 MHz channels
802.11ac	5 GHz only	6.93 Gbps	35m indoor	MU-MIMO, 160 MHz channels
802.11ax (WiFi 6)	2.4/5 GHz	9.6 Gbps	Similar to ac	OFDMA, BSS coloring

Notes

Always check physical layer first - 80% of WiFi issues are signal-related, not configuration problems
Use 5 GHz whenever possible for better performance, but remember 2.4 GHz for IoT device compatibility
Channel width vs range tradeoff - Wider channels (80/160 MHz) provide higher speeds but reduce range and increase interference susceptibility
Enterprise networks should implement 802.11k/v/r for seamless roaming, while home networks rely on client intelligence
Consider heat maps for large deployments to identify coverage gaps and interference zones
WiFi 6E (6 GHz band) provides additional spectrum but requires compatible clients and may have regulatory restrictions
Security note - WPA3 is preferred over WPA2, but ensure client compatibility before deployment