nerdexam
Cisco

300-425 · Question #8

An engineer must decide the cell overlap for a wireless voice deployment. Which Cisco measurement recommendation should be considered?

The correct answer is A. The edge of the cell should be -67 dBm. Cisco recommends designing wireless voice cells so that the cell edge maintains a minimum signal strength of -67 dBm, ensuring sufficient overlap for seamless roaming handoffs.

Wireless Design

Question

An engineer must decide the cell overlap for a wireless voice deployment. Which Cisco measurement recommendation should be considered?

Options

  • AThe edge of the cell should be -67 dBm.
  • BThe edge of the cell should be below 35 RSSI.
  • CThe measurement should be done on the 2.4-GHz band.
  • DOne AP should be deployed per 3000 square feet.

How the community answered

(24 responses)
  • A
    96% (23)
  • B
    4% (1)

Why each option

Cisco recommends designing wireless voice cells so that the cell edge maintains a minimum signal strength of -67 dBm, ensuring sufficient overlap for seamless roaming handoffs.

AThe edge of the cell should be -67 dBm.Correct

Cisco's wireless voice design guide specifies that the edge of each RF cell should be at -67 dBm to guarantee enough signal overlap between adjacent APs. This overlap ensures that a roaming client always has at least one AP above the minimum voice quality threshold during a handoff, preventing call drops.

BThe edge of the cell should be below 35 RSSI.

RSSI is expressed in dBm (a negative value), not as a unitless integer like 35 - '35 RSSI' is not a valid Cisco measurement unit for signal strength.

CThe measurement should be done on the 2.4-GHz band.

Cisco recommends performing voice site surveys and cell design on the 5-GHz band, not 2.4 GHz, due to its higher capacity, less interference, and better suitability for voice.

DOne AP should be deployed per 3000 square feet.

Cisco does not use a fixed square-footage rule for voice AP density - cell design is based on measured RF signal levels (dBm) at the cell edge, not area calculations.

Concept tested: Wireless voice cell overlap and edge signal design

Source: https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Mobility/vowlan/41dg/vowlan41dg-book/vowlan_ch3.html

Topics

#voice WLAN design#cell overlap#RSSI threshold#coverage requirements

Community Discussion

No community discussion yet for this question.

Sign up to join the discussion
Full 300-425 Practice