Unstable indicates that one or both network adapters linked by a physical connection are unstable. A network adapter is considered unstable if it alternates between up and down states over a short period of time:
A Cable Unstable diagnosis supersedes a Port Unstable or Interface Unstable diagnosis if a cable connects a port or an interface that is unstable.
A TrunkCable Unstable diagnosis supersedes a Port Unstable diagnosis if a trunk cable connects a port that is unstable.
A NetworkConnection Unstable diagnosis supersedes an Interface Unstable diagnosis if a NetworkConnection connects an interface that is unstable to another interface.
The event used to diagnose device connection Unstable is network adapter DownOrFlapping. To distinguish device connection Unstable from device connection Down, the value of the IsNetworkAdapterFlapping attribute of the device connection object must also be set to TRUE.