⚡ Quick overview
Wireless networking uses radio waves to transmit data without physical cables. The IEEE 802.11 standard defines how Wi-Fi works — different versions (802.11a/b/g/n/ac/ax) offer different speeds and frequency bands. WPA3 is the current security standard; WEP and WPA are deprecated and broken. All three CompTIA exams test wireless standards, security protocols, and common wireless attacks.
802.11 wireless standards — the complete reference table
Every 802.11 standard has a maximum theoretical speed, frequency band, and Wi-Fi generation name. The exam tests these details — particularly which standard introduced which frequency band and the generational Wi-Fi names:
| Standard | Wi-Fi Name | Frequency | Max Speed | Status |
|---|---|---|---|---|
| 802.11a | Wi-Fi 1 | 5 GHz | 54 Mbps | Legacy |
| 802.11b | Wi-Fi 2 | 2.4 GHz | 11 Mbps | Legacy |
| 802.11g | Wi-Fi 3 | 2.4 GHz | 54 Mbps | Legacy |
| 802.11n | Wi-Fi 4 | 2.4 GHz / 5 GHz | 600 Mbps | Common |
| 802.11ac | Wi-Fi 5 | 5 GHz | 3.5 Gbps | Common |
| 802.11ax | Wi-Fi 6 / 6E | 2.4 / 5 / 6 GHz | 9.6 Gbps | Current |
⚡ 802.11 memory shortcuts
802.11a = first to use 5 GHz (remember: "a" = alone on 5 GHz initially)
802.11b/g = both 2.4 GHz only — most prone to interference (microwaves, Bluetooth)
802.11n = first dual-band standard (2.4 AND 5 GHz) — introduced MIMO
802.11ac = 5 GHz only, much faster — MU-MIMO, beamforming
802.11ax = Wi-Fi 6, adds 6 GHz band (in 6E variant) — most efficient in dense environments
2.4 GHz vs 5 GHz — the key tradeoff
Frequency band comparison
2.4 GHz Advantages: Longer range, better penetration through walls Disadvantages: Slower, more interference (microwaves, Bluetooth, neighbours) Only 3 non-overlapping channels (1, 6, 11) in 20 MHz width Standards: 802.11b, 802.11g, 802.11n 5 GHz Advantages: Faster speeds, less interference, more non-overlapping channels Disadvantages: Shorter range, worse wall penetration Up to 25 non-overlapping channels Standards: 802.11a, 802.11ac, 802.11n (dual-band), 802.11ax
Wireless security protocols — WEP, WPA, WPA2, WPA3
Wireless security protocols encrypt traffic between devices and access points. This progression from WEP to WPA3 is one of the most consistently tested topics across A+, Network+, and Security+:
⚠️ Broken — Never Use
WEP
Wired Equivalent Privacy (1999)
RC4 stream cipher — fundamentally flawed
Can be cracked in minutes with basic tools
Appears on exam as example of weak security
No legitimate use case today
✓ Secure — Widely Deployed
WPA2
Wi-Fi Protected Access 2 (2004)
AES-CCMP encryption — strong
Personal (PSK) and Enterprise (802.1X) modes
Vulnerable to KRACK attack (2017) — patched
Still widely used and acceptable
✓✓ Current Standard
WPA3
Wi-Fi Protected Access 3 (2018)
SAE (Simultaneous Authentication of Equals) replaces PSK handshake
Forward secrecy — past sessions protected if key compromised
192-bit security suite for enterprise
Required on new Wi-Fi 6 certified devices
⚡ WPA2 Personal vs Enterprise
WPA2 Personal (PSK): Everyone uses the same pre-shared key. Simple to set up but if the key is compromised everyone is affected. Used in homes and small offices.
WPA2 Enterprise (802.1X): Each user authenticates with individual credentials via a RADIUS server. More secure and scalable — used in corporate environments. If one user's credentials are compromised, others are not affected.
The exam will ask which is appropriate for a business with 200 employees — always Enterprise/802.1X.
Wireless network components
| Component | What it does | Exam note |
|---|---|---|
| Access Point (AP) | Connects wireless clients to a wired network — bridges wireless and wired | Unlike a router, a standalone AP only handles wireless — doesn't route traffic |
| Wireless Router | AP + router + switch in one device — typical home network device | Routes between wireless clients and the internet |
| SSID | Service Set Identifier — the name of the wireless network | Hiding the SSID is security through obscurity — not effective protection |
| BSS / ESS | Basic Service Set = single AP. Extended Service Set = multiple APs with same SSID | ESS allows roaming between APs — enterprise Wi-Fi deployments use ESS |
| MIMO / MU-MIMO | Multiple Input Multiple Output — uses multiple antennas to increase throughput | Introduced in 802.11n. MU-MIMO (multiple users simultaneously) in 802.11ac/ax |
| Channel | Specific frequency range within a band used for communication | On 2.4 GHz use channels 1, 6, or 11 to avoid overlap with neighbouring APs |
Wireless attacks
| Attack | How it works | Defence |
|---|---|---|
| Evil Twin / Rogue AP | Attacker sets up a fake AP with the same SSID as a legitimate network to intercept traffic | Wireless intrusion detection, certificate-based authentication (802.1X) |
| Deauthentication Attack | Sends forged deauth frames to disconnect clients — often used to capture WPA handshakes | 802.11w (Management Frame Protection), WPA3 |
| WPS Attack | Wi-Fi Protected Setup PIN is only 8 digits — brute-forceable in hours | Disable WPS entirely on all access points |
| Wardriving | Driving around to discover and map wireless networks using a laptop and antenna | Strong encryption (WPA3), avoid broadcasting SSID (limited protection) |
| KRACK Attack | Key Reinstallation Attack — exploits WPA2 four-way handshake to reinstall an already-used key | Patched via firmware updates — keep devices updated |
| Jamming | Flooding the frequency with noise to prevent legitimate wireless communication — denial of service | Difficult to fully prevent — detect with spectrum analyser, change channels |
Wi-Fi 6 and Wi-Fi 6E — Network+ Deep Dive
Wi-Fi 6 (802.11ax) introduced several technologies that the Network+ exam specifically tests. Understanding what each technology does — and why — is more important than memorising the acronyms alone.
| Technology | What It Does | Benefit |
|---|---|---|
| OFDMA | Orthogonal Frequency Division Multiple Access — divides channels into sub-channels (resource units) | Multiple devices transmit simultaneously on one channel — eliminates the "take turns" limitation of older Wi-Fi |
| MU-MIMO (8×8) | Multi-User MIMO expanded to 8 simultaneous spatial streams (up from 4 in Wi-Fi 5) | AP serves 8 clients simultaneously rather than sequentially |
| BSS Coloring | Tags each BSS (network) with a colour so devices can distinguish overlapping networks on the same channel | Reduces interference in dense deployments — devices ignore frames from other networks rather than waiting |
| TWT | Target Wake Time — AP schedules when IoT devices wake up to transmit | Dramatically improves battery life for IoT sensors and mobile devices |
| WPA3 required | Wi-Fi 6 certification mandates WPA3 support | SAE replaces PSK — resistant to offline dictionary attacks and provides forward secrecy |
| 6 GHz band (Wi-Fi 6E) | Wi-Fi 6E adds the 6 GHz spectrum (5.925–7.125 GHz) — 59 additional 20 MHz channels | Massive capacity in dense environments — stadiums, hospitals, offices. Less congestion than 5 GHz. |
⚡ Network+ exam tip — Wi-Fi 6 vs 6E vs Wi-Fi 7: Wi-Fi 6 = 802.11ax (2.4 + 5 GHz). Wi-Fi 6E = 802.11ax with 6 GHz band added. Wi-Fi 7 = 802.11be (adds 320 MHz channels and Multi-Link Operation). The exam tests 802.11ax specifically — know OFDMA and BSS Coloring as the defining features.
Site Surveys — Planning and Validating Wireless Deployments
A wireless site survey is the process of planning, deploying, and validating a wireless network's coverage and performance. Network+ tests all three types — and Security+ tests the security implications of rogue AP detection during surveys.
| Survey Type | When Used | What It Involves |
|---|---|---|
| Passive Survey | Before deployment — planning phase | Walk the area with a laptop in monitor mode, capturing existing RF signals without transmitting. Maps interference sources and existing networks. No APs required. |
| Active Survey | During/after deployment — validation | Associates with APs and measures actual throughput, signal strength (RSSI), and SNR at various locations. Requires APs to be installed. |
| Predictive Survey | Pre-deployment — uses software modelling | Uses floor plan software to model RF propagation based on building materials and AP placement. Produces heat maps without physical walkthrough. Less accurate than active survey. |
Key Site Survey Metrics
| Metric | Description | Target Value |
|---|---|---|
| RSSI | Received Signal Strength Indicator — measures how strong the signal is at the client | -65 dBm or better for good performance; -80 dBm = weak; -90 dBm = unusable |
| SNR | Signal-to-Noise Ratio — difference between signal strength and background noise floor | 25 dB minimum; 40+ dB excellent. Low SNR = interference problem even with good RSSI. |
| Channel utilisation | Percentage of time the channel is in use | Below 50% — above 80% causes performance degradation |
| Heat map | Visual representation of signal strength coverage across a floor plan | Tool output — identifies dead zones and areas of overlap between APs |
⚡ Network+ exam tip — interference sources: Common sources of 2.4 GHz interference include microwave ovens, baby monitors, Bluetooth devices, and neighbouring Wi-Fi networks. The 5 GHz band has less interference but shorter range. A spectrum analyser identifies RF interference sources that a standard Wi-Fi adapter cannot.
EAP Types — 802.1X Authentication (Security+)
When using WPA2/WPA3 Enterprise, clients authenticate via 802.1X — which uses EAP (Extensible Authentication Protocol) as the authentication framework. Security+ tests the specific EAP types and what makes each one secure or insecure.
| EAP Type | Authentication Method | Security Level | Exam Note |
|---|---|---|---|
| EAP-TLS | Mutual certificate-based — both client AND server present certificates | Strongest | Most secure but requires PKI infrastructure to issue client certs — high overhead |
| PEAP | Protected EAP — server cert only, client uses username/password inside TLS tunnel | Strong | Most common in enterprises — no client certs needed. Uses MSCHAPv2 inside the tunnel. |
| EAP-TTLS | Tunnelled TLS — server cert only, supports any inner auth method inside tunnel | Strong | More flexible than PEAP — can use PAP or CHAP inside tunnel. Common on Linux clients. |
| EAP-FAST | Flexible Authentication via Secure Tunnelling — uses Protected Access Credentials (PACs) | Moderate | Cisco proprietary — designed for environments where PKI is impractical |
| LEAP | Lightweight EAP — early Cisco proprietary, username/password only | Weak — deprecated | Vulnerable to offline dictionary attacks — replaced by EAP-FAST. Do not use. |
802.1X flow — how it works: Client (Supplicant) → Switch/AP (Authenticator) → RADIUS Server (Authentication Server). The switch/AP passes EAP messages between the client and the RADIUS server. The client is in an unauthorised state until RADIUS approves — only EAPOL frames pass through. Once authenticated, the port opens for normal traffic.
Channel Bonding and Antenna Types
Channel Bonding
Channel bonding combines adjacent channels to increase bandwidth. A standard channel is 20 MHz wide. Bonding doubles or quadruples that width for higher throughput — at the cost of using more spectrum and increasing potential interference.
| Width | Channels Bonded | Use Case | Tradeoff |
|---|---|---|---|
| 20 MHz | 1 channel | Dense deployments, 2.4 GHz | Lower throughput, less interference |
| 40 MHz | 2 bonded | 802.11n, moderate density | 2× throughput; only 1 non-overlapping channel on 2.4 GHz — avoid bonding on 2.4 GHz |
| 80 MHz | 4 bonded | 802.11ac, good for 5 GHz | High throughput; uses significant spectrum |
| 160 MHz | 8 bonded | 802.11ax/Wi-Fi 6, 6 GHz band | Maximum throughput — only practical on 6 GHz where spectrum is available |
Antenna Types
| Antenna Type | Pattern | Best Use Case |
|---|---|---|
| Omnidirectional | 360° horizontal radiation — broadcasts in all directions equally | General office/home coverage — most common AP antenna |
| Directional (Yagi) | Focused beam in one direction — high gain, narrow pattern | Point-to-point links between buildings — long distance, targeted coverage |
| Directional (Patch) | Flat panel, forward-focused | Corridors, warehouses — covers a specific area without radiating behind |
| Parabolic dish | Very high gain, extremely narrow beam | Long-distance point-to-point links — miles between sites |
Wireless Troubleshooting Methodology
Network+ and Security+ both include wireless troubleshooting scenarios. The methodology follows a logical pattern — identify symptoms, isolate the layer, and test fixes in order.
Exam scenarios
💬 "Which 802.11 standard operates on the 5 GHz band and offers speeds up to 3.5 Gbps?" → 802.11ac (Wi-Fi 5)
💬 "A company needs wireless security where each employee logs in with individual credentials. What should they implement?" → WPA2 Enterprise with 802.1X / RADIUS
💬 "Which wireless security protocol is considered broken and should never be used?" → WEP
💬 "A user connects to what appears to be the corporate Wi-Fi but their credentials are being captured. What type of attack is this?" → Evil Twin / Rogue AP
💬 "Which 802.11 standard was the first to support both 2.4 GHz and 5 GHz?" → 802.11n (Wi-Fi 4)
💬 "An organisation wants to allow employees to roam between multiple access points without reconnecting. What should they configure?" → ESS (Extended Service Set) with the same SSID
💬 "Which wireless feature should be disabled because its 8-digit PIN can be brute-forced?" → WPS (Wi-Fi Protected Setup)
💬 "A 2.4 GHz network is experiencing interference from a neighbouring network. Which channels avoid overlap?" → Channels 1, 6, and 11
💬 "Which WPA3 feature protects previously recorded traffic if the encryption key is later compromised?" → Forward secrecy (via SAE)
💬 "An attacker sends forged frames to disconnect wireless clients from an AP. What attack is this?" → Deauthentication attack
💬 "A network engineer needs to plan AP placement before installation. Which type of site survey uses software modelling rather than physical walkthrough?" → Predictive survey
💬 "After deploying APs, a technician walks the building measuring actual signal strength and throughput. What type of survey is this?" → Active survey
💬 "A wireless network requires each user to authenticate with a digital certificate — both the client and server present certificates. Which EAP type is this?" → EAP-TLS
💬 "An enterprise needs 802.1X authentication but cannot deploy client certificates. Which EAP type uses only a server certificate with username/password inside a TLS tunnel?" → PEAP
💬 "Wi-Fi 6 introduces which technology that allows multiple devices to transmit on the same channel simultaneously by dividing it into sub-channels?" → OFDMA
💬 "Users in a dense office environment report that despite strong signal, Wi-Fi performance is poor. The same channel is used by three nearby networks. What is the likely cause and solution?" → Co-channel interference — change AP channels so nearby networks use non-overlapping channels (1, 6, 11 on 2.4 GHz)
💬 "Which wireless antenna type is most appropriate for a point-to-point link between two buildings 500 metres apart?" → Directional antenna (Yagi or parabolic dish)
💬 "A device connects to Wi-Fi successfully but receives a 169.254.x.x address. What is the problem?" → DHCP failure — the device fell back to APIPA. Check DHCP server availability and scope lease pool.
Studying for Network+ or Security+?
The study guides, practice exams, and free courses worth your time for both certifications.