segment type (ATM) (ST)

The segment type( ST) identification field is a data field in ATM headers and DQDB headers.

In Distributed Queue Dual Bus (DQDB), it identifies cells according to whether they are a single segment or whether they are the first, last, or intermediate segment of a MAC frame.

In ATM, it is the identification field used to identify the portion of the SAR SDU that is in that SAR PDU: Begin Of Message( BoM), Continuation Of Message( COM), End Of Message( EOM) or Single Segment Message( SSM).