EXFO FTB-8510B Guia Del Usuario página 1325

Figure LCAS Protocol Transmission on page 674 represents a NE1 source
that sends a CTRL packet [1] to the NE2 sink. The NE2 sink receives the
CTRL packet and processes it. In addition to the result of this processing,
the detected status of its own members is shared with the NE2 source via
an internal communication path [2]. At this point, using the return path, the
NE2 source sends its own CTRL packet [3], which contains its own CTRL
information as well as the NE2 sink information. The LCAS protocol loop is
closed when the NE1 sink shares the information that is received from the
NE2 sink to the NE1 source via the internal communication path [4]. This
information transfer is also done in the same manner if the described
scenario originates from the NE2 Source.
LCAS Control Packets
Below is the list of ITU-defined control packets for both directions of an
LCAS signaling link.
ITU-Defined LCAS Control Packets
FIXED Indicates that this end uses fixed bandwidth (non-LCAS mode).
ADD
NORM Indicates that there is no change; steady state.
IDLE
EOS
DNU
SONET/SDH Application
Indicates that this member is about to be added to the group.
Indicates that this member is not part of the group or about to be
removed.
Indicates the end of sequence; normal transmission.
Means do not use payload; indicates that the Sk side reported FAIL
status.
Next-Gen - Link-Capacity Adjustment Scheme (LCAS)
Glossary
675