Wireless Frequencies
A Network+ (N10-009) study guide to the 802.11 standards table, IEEE designation, Wi-Fi generation, frequency, and maximum data rate
Why this table is worth memorizing cold
Network+ loves to hand you a scenario, "a client device only supports 5 GHz and needs at least 1 Gbps throughput", and expect you to know, instantly, which 802.11 standard(s) qualify. That means you need more than a vague sense that "newer Wi-Fi is faster." You need the actual mapping between the IEEE standard name, the marketing generation number, the frequency band(s) it uses, and its maximum data rate, cold, without a lookup.
The one sentence to memorize: Every jump in Wi-Fi generation brought either a new frequency band, a new modulation/channel technique, or both, and the exam tests whether you know which standard unlocked which capability, not just the numbers in isolation.
The master reference table
| IEEE Standard | Wi-Fi Generation | Frequency | Maximum Data Rate |
|---|---|---|---|
| 802.11 (original, 1997) | (pre-dates generation naming) | 2.4 GHz | 2 Mbps |
| 802.11a | — | 5 GHz | 54 Mbps |
| 802.11b | — | 2.4 GHz | 11 Mbps |
| 802.11g | — | 2.4 GHz | 54 Mbps |
| 802.11n | Wi-Fi 4 | 2.4 GHz and 5 GHz | 600 Mbps (with 4x4 MIMO) |
| 802.11ac | Wi-Fi 5 | 5 GHz only | ~6.9 Gbps (theoretical, 8 spatial streams, 160 MHz channels) |
| 802.11ax | Wi-Fi 6 / Wi-Fi 6E | 2.4 GHz and 5 GHz (Wi-Fi 6); adds 6 GHz (Wi-Fi 6E) | ~9.6 Gbps (theoretical) |
| 802.11be | Wi-Fi 7 | 2.4 GHz, 5 GHz, and 6 GHz (tri-band) | ~23 Gbps per link (theoretical; higher aggregate figures assume Multi-Link Operation across bands) |
"Maximum data rate" is a theoretical ceiling, not a real-world number. These figures assume ideal conditions: maximum spatial streams, widest channel width, no interference, and a compatible client on both ends. The exam sometimes tests this directly; a question describing poor real-world throughput on an "ac" network isn't necessarily describing a misconfiguration; it may just be normal behavior relative to the theoretical max.
Walking through each generation
802.11 / 802.11a / 802.11b / 802.11g, the legacy standards. These predate the "Wi-Fi generation" marketing numbers entirely (the Wi-Fi Alliance introduced that naming scheme starting with 802.11n, retroactively). Two details matter for the exam: 802.11b and 802.11g both operate at 2.4 GHz and are backward-compatible with each other, while 802.11a operates at 5 GHz and is not compatible with 802.11b/g clients; mixed-mode questions about legacy devices failing to connect often hinge on this exact mismatch.
802.11n (Wi-Fi 4). The first standard to carry a "Wi-Fi generation" number, and the first to operate on both 2.4 GHz and 5 GHz, a dual-band capability that's been standard ever since. It introduced MIMO (Multiple Input, Multiple Output), using multiple antennas to send/receive multiple spatial streams simultaneously, which is how it reaches its much higher ceiling than 802.11g.
802.11ac (Wi-Fi 5). A 5 GHz-only standard, this is a frequent exam trap, since candidates sometimes assume every generation supports both bands. 802.11ac introduced MU-MIMO (Multi-User MIMO), letting an access point communicate with multiple client devices' spatial streams at once rather than serving clients one at a time, and widened channels up to 160 MHz.
802.11ax (Wi-Fi 6 and Wi-Fi 6E). Wi-Fi 6 operates on the same 2.4/5 GHz bands as Wi-Fi 4/5 but adds OFDMA (Orthogonal Frequency-Division Multiple Access), which subdivides channels so an access point can serve multiple clients' data within the same transmission interval, a major efficiency gain in dense environments. Wi-Fi 6E is the same 802.11ax standard extended to operate in the newly opened 6 GHz band, which offers substantially more non-overlapping channels and far less legacy-device congestion than 2.4 or 5 GHz.
802.11be (Wi-Fi 7). Tri-band by design (2.4/5/6 GHz simultaneously) and built around Multi-Link Operation (MLO), the ability for a single client to use more than one band/channel at the same time for one connection, improving both throughput and reliability. This is the newest standard likely to appear on current exam material, primarily at the recognition level (name, generation number, and tri-band capability).
The frequency trade-off you need to reason through, not just memorize
Beyond the table itself, Network+ tests whether you understand why a network engineer would choose one band over another:
| 2.4 GHz | 5 GHz | 6 GHz | |
|---|---|---|---|
| Range | Longest (better wall/obstacle penetration) | Moderate | Shortest |
| Throughput potential | Lowest | Higher | Highest |
| Available non-overlapping channels | Very few (effectively 3 in most regions: 1, 6, 11) | Many more | Most of all, newest, least congested band |
| Interference | High, shared with Bluetooth, microwaves, cordless phones, and nearly every legacy device | Moderate | Lowest; only newer (Wi-Fi 6E/7) devices can even use it |
Exam framing: a scenario describing a large warehouse needing maximum coverage with modest throughput needs typically points toward 2.4 GHz (or a dual-band AP prioritizing 2.4 GHz); a scenario describing a dense office needing high throughput with many concurrent devices points toward 5 GHz or 6 GHz.
Common exam gotchas, summarized
- "Wi-Fi generation" numbers only exist starting with Wi-Fi 4 (802.11n). 802.11a/b/g are referred to by their IEEE letter designations only; there's no "Wi-Fi 1/2/3" in common exam usage.
- 802.11b and 802.11g share 2.4 GHz and are backward-compatible; 802.11a is 5 GHz and is not compatible with either. Mixed-network connectivity questions often hinge on this exact split.
- 802.11ac (Wi-Fi 5) is 5 GHz only; it does not operate at 2.4 GHz, unlike the generations before and after it.
- Wi-Fi 6E is not a separate IEEE standard from Wi-Fi 6; both are 802.11ax. "6E" specifically denotes 6 GHz band support layered onto the same standard.
- Maximum data rates are theoretical ceilings, assuming ideal spatial streams, channel width, and no interference; never treat them as guaranteed real-world throughput.
- Higher frequency = higher potential throughput but shorter range and worse obstacle penetration. This inverse relationship is the reasoning skill behind most band-selection scenario questions.
Practice-style questions
1. A network technician needs to support a client device that only has a 2.4 GHz radio and requires backward compatibility with older 802.11b hardware still in use. Which standard satisfies both requirements? 802.11g: It operates at 2.4 GHz and is backward-compatible with 802.11b.
2. Which Wi-Fi generation was the first to introduce dual-band (2.4 GHz and 5 GHz) operation on a single standard? Wi-Fi 4 (802.11n).
3. An administrator wants to deploy the newest available Wi-Fi standard to take advantage of the 6 GHz band's lower congestion. Which two standards support 6 GHz? Wi-Fi 6E and Wi-Fi 7 (802.11ax with the 6E extension and 802.11be) support 6 GHz; standard Wi-Fi 6 (802.11ax without the "E") does not.
4. Why does 802.11ac (Wi-Fi 5) typically achieve better throughput than 802.11n (Wi-Fi 4) in the same environment, despite both supporting MIMO? 802.11ac adds MU-MIMO (serving multiple clients' streams simultaneously rather than one at a time), supports wider channels (up to 160 MHz vs. 802.11n's 40 MHz), and operates exclusively in the less congested 5 GHz band.
Quick-reference cheat sheet
| Standard | Generation | Band(s) | Max Rate |
|---|---|---|---|
| 802.11 | — | 2.4 GHz | 2 Mbps |
| 802.11a | — | 5 GHz | 54 Mbps |
| 802.11b | — | 2.4 GHz | 11 Mbps |
| 802.11g | — | 2.4 GHz | 54 Mbps |
| 802.11n | Wi-Fi 4 | 2.4 + 5 GHz | 600 Mbps |
| 802.11ac | Wi-Fi 5 | 5 GHz | ~6.9 Gbps |
| 802.11ax | Wi-Fi 6 / 6E | 2.4 + 5 GHz (+6 GHz on 6E) | ~9.6 Gbps |
| 802.11be | Wi-Fi 7 | 2.4 + 5 + 6 GHz | ~23 Gbps (per-link) |
Further study: CompTIA's official N10-009 exam objectives document (Domain 1.5 transmission media / Domain 2.3 wireless devices and technologies) for the authoritative, current wording of the wireless material.