Wireless Location Services AP Hearing Requirements

Answer Correct answer: D — At least four APs must be heard by each location-ready AP at a signal level of -75 dBm or better to ensure accurate location tracking.

When a wireless network is designed for location services, how many APs must be heard by each location-ready AP at a signal level of -75 dBm or better?

three APs
no more than three APs
two APs
at least four APs Correct Answer

cisco location based services wireless ap hearing requirements 300-425 exam questions location ready ap design

Community Votes

43%

29%

43% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Community Insight

The exam tests the distinction between client-side triangulation (3 APs) and the AP-to-AP hearing requirement for location-ready nodes (4 APs), with -75 dBm being the critical signal threshold.

This question examines the specific RF design requirements for location-based services in Cisco wireless networks, focusing on how many access points must hear a location-ready AP. The correct answer is derived from official deployment models that prioritize accuracy over minimum connectivity.

Most candidates choose 'three APs' because they associate location services with standard 2D triangulation, failing to recognize that location-ready APs require a more robust mesh of at least four neighbors for reliable positioning data.

Community Discussion (9 comments)

55f2ace 👍 1 Selected: A

Cisco guide: Location Deployment Model Ideally, a wireless design should have enough APs distributed across the covered area such that a signal from any device location can be received by at least three APs.

rlss92 👍 1 Selected: D

For accurate location tracking, Cisco recommends that each location-ready AP be heard by at least four other APs at a signal level of -75 dBm or better. This ensures sufficient RF triangulation for accurate client positioning, as at least three APs are needed for 2D location, but a fourth AP improves accuracy and reliability. This design principle enhances the precision of location-based services, such as asset tracking or location analytics.

AdamNoe 👍 1 Selected: A

Hyperlocation Basic Rule: Deploy minimum of 4xAP on each floor so answer is A. three APs

a8cb452 👍 2 Selected: C

3 APs for triangulation but it asks how many APs can one AP see. Not how many APs a client can see. Each AP must see 2 others (for a total of 3), or we assume a client at that location can't see 3 APs.

e9cc965 👍 1 Selected: A

3 aps for location

zyxzyx123 👍 1

If its a client then its 3 AP's for triangulation, but if its an AP with say NDP packages, then the answer must be 2, as it again takes 3 AP's in total for triangulation. It almost feels like a trick question with that choice of wording.

Farhad123 👍 1

3 Aps. This is text from Cisco certification guide: If location-based services are required, your design goal should be to provide good RF coverage and an effective AP layout. APs should be positioned such that multiple APs can receive a signal from a device to be located. A minimum of three APs should be able to receive a client’s signal, while four or more APs are preferred. You should think of every possible client location having at least one AP in each surrounding quadrant. To derive a fairly accurate location, multiple APs must receive the client device or tag at an RSSI above a minimum signal level of –75 dBm. When you perform a site survey, you should use a threshold of –72 dBm, which will give a 3 dB buffer over the absolute minimum.

AmrOoooo 👍 1 Selected: D

D. at least four APs >>> To ensure precise location tracking, location-based services often require a minimum of four access points to be within the hearing range of each location-ready AP at a signal level of -75 dBm or better. This allows for more accurate triangulation of the AP's position, which is crucial for precise location-based services.

Bandito 👍 2

strange question. -75dBm is the requirement for the tracking device to be head by at least three APs. Not about APs hearing each other.

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Expert Analysis

Why the Answer Is Correct

For accurate location tracking using location-based services, Cisco recommends that each location-ready AP be heard by at least four other APs at a signal level of -75 dBm or better. While three APs are sufficient for basic 2D triangulation of a client device, a fourth AP is required to improve accuracy, reliability, and to handle potential signal obstructions or errors in the calculation. This ensures that the system has enough redundant data points to pinpoint the location effectively.

Why the Other Options Are Wrong

Option A (three APs) represents the absolute minimum for client triangulation but is insufficient for the robust design required for location-ready APs. Option C (two APs) provides no geometric basis for 2D positioning. Option B (no more than three APs) contradicts the need for redundancy and increased data points for high-precision location services.

Community Comment Notes

Community members frequently debated this due to the wording "heard by." As user Bandito noted, it's crucial to distinguish between what a client sees versus what an AP hears. User rlss92 correctly identified that Cisco guides recommend at least four APs for precise tracking. Some users like AdamNoe referenced the Hyperlocation rule of deploying 4xAP per floor, supporting the higher count requirement for location readiness.

Exam Strategy

When studying location-based services, memorize the -75 dBm threshold and the difference between client triangulation (3 APs) and location-ready AP requirements (4 APs). Always look for keywords like 'location-ready' or 'tracking device' which often imply stricter design criteria than general Wi-Fi coverage.

Frequently Asked Questions

Why not just 3 APs for location?

Three APs allow for basic 2D triangulation, but four APs are required for location-ready designs to ensure accuracy, reliability, and handling of signal variations.

What is the -75 dBm threshold?

It is the minimum signal strength required for a location-ready AP to be considered 'heard' by another AP for the purpose of calculating position data.

Related Analysis

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