MVID 02h - Beacon - BCN
Destination Address: C0-00-FF-FF-FF-FF (ring multicast / 'this ring')
Destination Class: 0 (ring station)
Source Class: 0 (ring station)
Subvectors: SVID 0Bh - Physical Drop Number
If a station detects severe ring errors, it will start a beacon alarm.
Signal Loss:
Only 'J' codes can be detected (no valid signal).
TNT (Timer, No Token) Expired / no FR_CL_TK received:
The allowd token rotation time expired; there were no 'claim token' frames received which indicates that upstream stations did not detect error conditions concerning the token.
TNT (Timer, No Token) Expired / FR_CL_TK received:
The allowed token rotation time expired; there were 'claim token' frames received which indicates that upstream station already detected error conditions concerning the token.