This is an accessible-for-notify Integer32, meaning it's only reported via trap rather than polled, representing the number of entries in the MEC tunnel cache table. It's carried as the payload of the hh3cMecTunnelCacheFullTrap and hh3cMecTunnelCacheRecoverTrap notifications, letting the device report when the tunnel cache becomes full or recovers below the normal threshold. For example, when hh3cMecTunnelCacheFullTrap fires with hh3cMecTunnelCacheNumber at the table's capacity, an admin knows new MEC tunnels can't be established until entries are freed.