This read-only integer reports the lowest receive signal level, in dBm, the link interface has recorded since it last started up. An engineer uses this to judge the worst-case fade the link has experienced, which is critical for assessing whether the configured fade margin has actually been tested by real conditions. For example, a wvlinkMinimumRSL far below the average would indicate a significant fade event occurred at some point during the current link session, even if the link never fully dropped.