The current state of the 7x50 APS forced Tx-LAIS on the specified
APS channel.
Note that the 7x50 products always receive and transmit on the same
(active) APS channel. For a Multi-Chassis (MC) APS or a unidirectional
APS group, the 7x50 product may transmit (Tx) L-AIS on the inactive
APS channel to force the remote end to receive traffic on the 7x50
selected active APS channel.
The state clear indicates that the 7x50 product currently doesn't
transmit any forced LAIS on the APS channel. The state momentary
indicates that the 7x50 product has transmitted forced LAIS on the APS
channel for a moment(e.g. 100 msec). The state persistent indicates
that the 7x50 product has been persistently transmitting forced LAIS on
the APS channel.