Wi-Fi Fundamentals — IEEE 802.11b Maximum Data Rate In the legacy 2.4GHz 802.11b standard (DSSS/CCK), what is the theoretical maximum physical layer (PHY) data rate?

Introduction / Context:
Before 802.11g/n/ac/ax, early Wi-Fi deployments relied on 802.11b operating at 2.4GHz using DSSS/CCK modulation. Memorizing the maximum PHY rate for 802.11b helps differentiate capabilities across generations of WLAN equipment.

Given Data / Assumptions:

• Standard is IEEE 802.11b.
• Question targets the PHY headline rate, not application throughput.
• Environment is ideal for the purpose of nominal rate.

Concept / Approach:
802.11b defined rates of 1, 2, 5.5, and 11Mbps using DSSS and CCK. Hence, the maximum data rate is 11Mbps. Remember that effective throughput at 11Mbps is far lower (often under 6Mbps TCP) due to medium contention, ACKs, and MAC overheads, especially in mixed b/g networks where protection mechanisms further reduce performance.

Step-by-Step Solution:
Identify modulation family: DSSS/CCK for 802.11b.Recall rate set: 1, 2, 5.5, 11Mbps.Select the highest value: 11Mbps.Confirm that 54Mbps is associated with 802.11a/g, not 11b.

Verification / Alternative check:
Any 802.11 reference table lists 11Mbps as the 802.11b maximum; routers/AP specs from the 2000s commonly show “802.11b: up to 11Mbps.”

Why Other Options Are Wrong:

• 6Mbps: OFDM basic rate for 802.11a/g; not 11b.
• 22Mbps: Proprietary extensions existed, but not part of the 802.11b standard.
• 54Mbps: 802.11a/g, not b.
• 2Mbps: A valid legacy rate but not the maximum.

Common Pitfalls:
Confusing vendor “Turbo” modes or mixed b/g overheads with standardized headline rates.

Final Answer:
11Mbps