This part of IEC 61334 covers the services required of, or by, the data communication protocol (DCP) logical link control (LLC) sublayer entity at the logical interfaces with the LLC-user layer and the MAC sublayer, using the connection-oriented LLC procedures. Services are specified showing the information flow between the LLC user and the MAC service, by describing the service primitives and parameters which characterize each service: these service primitives are those specified in IEC 61334-4-32 and in this standard, only the specific details and changes for connection-oriented procedures are given. The primitives in this standard are associated with the connection-oriented mode (CO) LLC protocol, providing connectionless services: a data transfer mode outside the connection context is also provided and harmonized with the CO procedures. The way to set up, close down and monitor the connection status is provided through services primitives to the LLC sublayer management entity and these services are not made available to the LLC user interface.