Positioned in the CCM statistics group, this counter, despite the generic 'valid frames received' wording in the MIB, counts CCM heartbeats received and accepted as valid from remote MEPs. Since CCMs are the mechanism CFM uses to detect a remote MEP going down or a fault appearing on the path, this counter's steady increase per remote-MEP CCM interval is the basic proof-of-life signal an admin relies on for that service. If a remote MEP that used to contribute one CCM per second to this total suddenly stops, this counter's growth rate visibly slows even while the device's other CFM traffic looks unaffected.