This part of final draft European Telecommunication Standard (ETS) 300 217 on the Connectionless Broadband Data Service (CBDS)@ describes the stage 1 of the switched bearer service provided via Metropolitan Area Networks (MANs) and/or an Asynchronous Transfer Mode (ATM) based network. It is applicable to both the public and private environment whereas special attention is paid to the requirements of the public operators. This bearer service category provides a means by which Protocol Data Units (PDUs) of variable@ but limited length@ are delimited and transparently transferred across one source interface to one or more destination interface(s) at the T reference point@ without establishing or later releasing a connection between source and destination. Charging principles are outside the scope of this final draft ETS. Whilst this bearer service category is aiming primarily at Local Area Network (LAN) interconnections@ other uses are envisaged.