The operating state of this SDP. The value
'notAlive' is valid only when keep-alive is
enabled, and it means that the keep-alive
operating status is not alive. The value
'notReady' is valid only when this SDP uses a
label signaling protocol (e.g. TLDP) and it means
that the signaling session with the far-end peer
has not been established. The value
'invalidEgressInterface' indicates that the
IOM's have detected that the egress interface
towards the far-end device is not a network
port.