EXFO IQS-8100 Series Transport Blazer for IQS-600 - Manual (Page 624)

Glossary
610 IQS-8100 Series Transport Blazer
G.709 Optical Transport Network (OTN)
Each of the six TCMi fields in the ODU overhead is assigned to a monitored
connection. There can be from zero to six connections that can be
configured for each connection. In the figure Tandem Connection
Monitoring on page 609, there are three different connections that are
actually monitored. Carrier C, due to its location, can monitor three TCM
levels as the ODU passes through its portion of the network.
In addition to monitoring maintenance signals, using the STAT field
associated with each TCM level, the TCM connection also monitors the
BIP-8 and BEI errors for each connection level. Maintenance signals are
used to advertise upstream maintenance conditions affecting the traffic
and errors provide an indication of the quality of service offered at each
segment of the network, which provides a valuable tool for the user and
carrier to isolate faulty sections of the network.