ESs: Errored Seconds encountered by a SONET/SDH Section
SESs: Severely Errored Seconds encountered by a SONET/SDH Section
SEFSs: Severely Errored Framing Seconds encountered by a SONET/SDH Section
CVs: Coding Violations encountered by a SONET/SDH Section
UASs:Unavailable Secondsencountered by a SONET/SDH