What is the purpose of the guard interval in an OFDM transmission?

To synchronize the access point and client

To reduce interference between symbols

In the 2.4 GHz band, what is the standard channel width used by most 802.11 networks, and how many non-overlapping channels are typically available?

40 MHz; 3 non-overlapping channels

20 MHz; 5 non-overlapping channels

20 MHz; 3 non-overlapping channels

40 MHz; 5 non-overlapping channels

A network administrator is configuring an 802.11ax AP for a conference room where many clients will be streaming video. They want to maximize the efficiency of the PHY layer. Which feature is most beneficial for improving efficiency in this dense scenario?

Set the AP to use only 20 MHz channels to reduce interference

Disable MIMO to reduce interference

Use a long guard interval to increase robustness

Enable OFDMA to allow multiple clients to share the same channel simultaneously

A network engineer is troubleshooting a performance issue on an 802.11n network. Clients are experiencing lower throughput than expected. The engineer notices that the AP is using a long guard interval (GI) instead of a short GI. What is the impact of using a long GI?

It provides better protection against multipath delay spread, but reduces throughput

It is required for 802.11n and cannot be changed

It has no effect on throughput, only on range

It increases data rates by allowing more symbols to be transmitted per second

Juniper NetworksCertified Specialist, Mist AI Wireless (JNCIS-MistAI)

Domain 1Objective 1

802.11 PHY Protocols JN0-452 Practice Questions (Page 2)

Part of the Wi-Fi Fundamentals domain, which makes up ~20% of our current practice bank. Juniper Networks does not publish an official question count, but from its 90-minute exam (~35–60 total, ~7–12 in this domain), expect 1–2 from this objective — we provide 16 practice questions to prepare you well beyond it. (estimate)

16questions here

4free pages

6concepts

Questions 6–10

6foundation · easy
What is the purpose of the guard interval in an OFDM transmission?
Select an answer first
7foundation · easy
In the 2.4 GHz band, what is the standard channel width used by most 802.11 networks, and how many non-overlapping channels are typically available?
Select an answer first
8application · medium
A network administrator is configuring an 802.11ax AP for a conference room where many clients will be streaming video. They want to maximize the efficiency of the PHY layer. Which feature is most beneficial for improving efficiency in this dense scenario?
Select an answer first
9foundation · easy
Which frequency band was introduced with 802.11ax (Wi-Fi 6E) and offers the most contiguous spectrum for wide channels?
Select an answer first
10application · medium
A network engineer is troubleshooting a performance issue on an 802.11n network. Clients are experiencing lower throughput than expected. The engineer notices that the AP is using a long guard interval (GI) instead of a short GI. What is the impact of using a long GI?
Select an answer first

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