USER NETRWORK INTERFACE CONFIGURATION
Reference points and functional grouping:
To define the requirement for ISDN user access, the first step is to group functions that may exist on the users premises, that suggest actual physical configuration.The figure below shows the ITU-T approach to this task using:
- Functional groupings
- Reference point
Reference points: Conceptual points used to separate groups of functions
It’s function associated with the physical and electrical termination of the ISDN.
They are:
- line transmission and termination
- line maintenance and performance monitoring
- timing
- power transfer
- layer 1 multiplexing
- interference
- termination including multi drop
- Termination employing layer 1 contention resolution
NETWORK TERMINATION-2:
- it’s functions are Layers 2 and 3 protocol handling
- Layers 2 and 3 multiplexing
- Switching
- Concentration
- Maintenance Function
- Interface termination and other Layer 1 Functions
TERMINAL EQUIPMENT TYPE-1(TE 1):
Two types are defined TE-1 refers to devices that support the standard ISDN interface. E.g.: Digital Telephone, Integrated voice/Data terminal and Digital facsimile equipment.
TERMINAL EQUIPMENT TYPE-2(TE 2)
These are terminals with a physical interference such as RS-232 and host computers with an X-25. Interface such equipments requires a terminal adaptor (TA) to plug into an ISDN interface.
REFERENCE POINT-T:
This corresponds to a minimal ISDN network termination at the customers premises. It separates the network providers equipment from the users equipment.
REFERENCE POINT-S
This corresponds to the interference of individual ISDN Terminals. It separates user terminal equipment from Network related Communication Functions.
REFERENCE POINT-R:
This provides a non ISDN Interference between user equipment that is not ISDN compatible and adopter equipment.
REFERENCE POINT-U:
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