This reports the CFM Maintenance Entity Group Level (MEL, 0-7) used by this virtual ring's continuity-check messages. The MEL has to match on every node around the ring for CFM continuity checks, and therefore ring fault detection, to work at all, so a MEL mismatch introduced by a config typo on just one node can silently blind that node to real faults on its ring segment while nothing looks obviously wrong in that node's own configuration. For example, if this virtual ring is set to MEL 4 on every node except one left at the device default of MEL 0, that one node simply won't process the ring's CCMs and could fail to detect a break in its own adjacent ring segment.