Information systems interconnection - ISDN - Provision of OSI connection-mode transport service over the OSI connection-mode network service by using an ISDN circuit-mode 64 kbit/s unrestricted bearer service - Demand case
This Functional Standard specifies a set of protocols to provide the function defined below. The requirements placed on an end system in this Functional Standard are solely those necessary for operation of the protocol set specified. It does not specify total end system capability.
This Functional Standard is defined in terms of the use of a single B channel for end-to-end communication between end systems, and the associated D channel required to control the connection across the ISDN. No distinction is made in this Functional Standard between the use of a B channel provided by a Basic interface and the use of a B channel provided by a Primary Rate interface. The use of multiple B channels to support a single Transport Layer connection is outside the scope of this Functional Standard.
This Functional Standard defines:
1 The provision of the OSI Connection-mode Transport Service [ISO 8072] between an end system (the "reference end system") attached to an ISDN (Public/Private), 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.
2 The provision of the OSI Connection-mode Network Service [ISO 8348] between the reference end system and the compatible end system.
This Functional Standard uses the X.25 PLP operating in the B channel to convey all the elements, of all three phases, of the OSI Connection-mode Network Service. The D channel is used only to establish and release the necessary circuit-switched connections across the ISDN.