Information technology - Functional standard for profiles T/C 4311 and T/D 4311 - ISDN (Public/Private) - Packet mode service - D-channel -Virtual call (VC)
This European Prestandard specifies a set of protocols to provide the function defined below. The requirements placed on an end system in this European Prestandard are solely those necessary for operation of the protocol set specified. It does not specify total end system capability.
This European Prestandard is defined in terms of the use of a D channel for Communications between end systems using the "no notification class". No distinction is made in this European Prestandard between the use of a D channel provided by a Basic interface and the use of a D channel provided by a Primary Rate interface.
This European Prestandard specifies :
a) the provision of the OSI Connection-mode Transport Service ISO 8072 between an end system (the "reference end system") attached to an ISDN, and another end system (the "compatible end system") which is either attached to the same ISDN, or is indirectly accessible through the provided network service;
b) the provision of the OSI Connection-mode Network Service [ISO 8348] between the reference end system and the compatible end system.
This European Prestandard uses the X.25 PLP operating in the D channel to convey all the elements, of all three phases, of the OSI CONS. In this access case, no Q 931 or prETS 300 102 call control message are needed at any point before or after the establishment of a virtual call or during the data transfer phase on an established virtual call.
The use of PVC is not within the scope of this European Prestandard because the OSI CONS is provided only by the use of Virtual Calls.