Applies to end systems involved with operation in the Open Systems Interconnection (OSI) environment. Defines a combination of OSI standards for collective provision of the connection-mode Transport Service by means of the connection-mode Network Service. Defines subnetwork-type dependent requirements applying to an end system attached to a local area network (LAN) subnetwork and which uses the ISO 8802-2 LLC type 2 protocol, regardless of the LAN medium.