This attribute specifies the state of the interface. The notReady
state, is the initial state of the service, when it is being initialized.
The localRestarting state is entered when a Restart packet is sent to
the link and the interface is waiting for a response. The
remoteRestarting state is entered when a Restart packet is received
from the link, and is being processed. In ready state, the service is
operational and ready to provide service.