RSSI is an acronym for Received Signal Strength Indicator. It is a measurement of the power level that a wireless client is receiving from an access point. This value is not an absolute unit like milliwatts (mW) or decibel-milliwatts (dBm) but is a relative index used by the radio chipset. Wireless devices use RSSI to assess the quality of a connection and to determine when it is necessary to roam to another access point with a better signal. In the Juniper Mist platform, the "Coverage" Service Level Expectation (SLE) is directly measured using client RSSI values.

A. Frequency is the rate of oscillation of a radio wave, measured in Hertz (Hz), and is not a measure of signal power.

C. Interference is unwanted radio frequency energy from other sources that can degrade a signal, but RSSI does not specifically isolate and measure it.

D. Noise refers to the background radio frequency energy (noise floor); RSSI measures the power of the desired signal, which is distinct from the noise floor.

1. Juniper Mist Documentation, Wi-Fi Assurance: In the section describing Service Level Expectations (SLEs), the "Coverage" metric is defined. It states, "The Coverage SLE measures the mobile clients’ ability to hear the APs at a sufficient signal strength. We measure this by looking at the client’s RSSI..." This directly links RSSI to the measurement of signal strength.

Source: Juniper Networks, "Wi-Fi Assurance," Service Level Expectations (SLEs) section.

2. Juniper Networks Technical Documentation, Radio Resource Management (RRM): The documentation for RRM explains how coverage holes are detected. It states, "The RRM feature detects coverage holes by monitoring the RSSI values of clients. If a client's RSSI drops below a configured threshold... the RRM feature identifies a coverage hole." This confirms RSSI is the metric for signal strength monitoring.

Source: Juniper Networks TechLibrary, "Radio Resource Management," Coverage Hole Detection section.

3. Peer-Reviewed Academic Publication: A study on wireless localization techniques defines RSSI as a fundamental concept. "RSSI is a measurement of the power present in a received radio signal... It is often used in wireless sensor networks for localization and distance estimation."

Source: Zafari, F., Gkelias, A., & Leung, K. K. (2019). A Survey of Indoor Localization Systems and Technologies. IEEE Communications Surveys & Tutorials, 21(3), 2568-2599. Section III-A, "Fingerprinting." DOI: https://doi.org/10.1109/COMST.2019.2911558