Is applicable to end systems concerned with operating in the Open Systems Interconnection environment. It specifies a combination of OSI standards, which collectively provide the connection-mode Transport Service using the connection-mode Network Service. Is applicable to the provision of the connection-mode Transport Service in end systems attached to any type of subnetwork from which the standardized connection-mode Network Service can be made available. Specifies the definition of profiles TB1111/TBE1121 in the TB group which uses Transport protocol classes 0, 2 und 4.