Slide 11 of 30
Notes:
- Receive goes up the stack, transmit goes down the stack.
- Size of data transmitted/received may fit into one data
link frame. So do not require multi-frame fragments or multi-fragment
messages.
- A single DNP application function is usually sent as a
single application layer message, which can consist of many data link
frames.
- IEC 870-5 has no transport layer. Each data link frame
containing application data is a complete application message. A single
application function (e.g.: interrogation) may require that several messages
are sent to complete the function.
