Received Signal Strength Indicator (RSSI) is a measurement of the power present in a received radio signal. In 802.11 wireless networking, this power level is most commonly expressed in dBm, which stands for decibels relative to one milliwatt. The dBm scale is logarithmic, making it ideal for representing the very wide range of signal power levels encountered in RF environments. A stronger signal is represented by a value closer to zero (e.g., -40 dBm), while a weaker signal has a more negative value (e.g., -85 dBm).

A. dBi: Measures the gain of an antenna relative to a theoretical isotropic antenna, not the received signal power.

C. Watts: A linear unit of power. While technically correct, it is not commonly used for displaying RSSI due to the large dynamic range of RF signals.

D. Ohms: The unit of electrical resistance and is unrelated to the measurement of signal power.

1. RUCKUS Unleashed 200.7 User Guide: In the section for monitoring wireless clients, the user interface displays a "Signal" column with values explicitly measured in dBm. For example, a client's signal strength is shown as "-54 dBm". (See Chapter: "Monitoring and Viewing Network Health," Section: "Wireless Clients," Page 161).

2. RUCKUS SmartZone 5.2.1 Administrator Guide: The client monitoring dashboard includes a column labeled "Signal (dBm)," which directly confirms that dBm is the unit used to display the received signal strength of connected clients. (See Chapter 11: "Monitoring Wireless Clients," Section: "Viewing Wireless Client Details," Page 398).

3. Kurose, J. F., & Ross, K. W. (2017). Computer Networking: A Top-Down Approach (7th ed.). Pearson. This foundational networking textbook explains that wireless signal strength is measured on a logarithmic scale, typically in dBm, to manage the vast differences between transmitted and received power. (See Chapter 6: The Link Layer and LANs, Section 6.3: Wireless Links and Networks).

4. Carnegie Mellon University, School of Computer Science, Course 15-441/641: Computer Networks, Fall 2017, Lecture 20: Wireless: The lecture slides explicitly state that signal strength is measured in dBm and provide a table correlating dBm values to signal quality (e.g., -30 dBm is "Excellent"). This confirms the academic and industry standard.