Token-Ring Frames

Token

Access permission is granted by the 3-bytes token frame (starting delimiter, access control, ending delimiter) with token bit set to zero (T=0).

Abort Sequence

If any adapter detetcts a corrupted token or certain local error conditions (adapter malfunction) it will abort the current transmission followed by transmission of an abort sequence (starting delimiter, ending delimiter); then the adapter will get off the ring for self test.

Data Frame

An adpater holding the token is allowed to transmit a frame; it sets the token bit (T=1) and adds protocol and user data (if any). This may be MAC frames (station management [SMT] data) or LLC frames (user data).