Service Primitives (simple example with 8 primitives)
CONNECT.request - Request a connection to be established
CONNECT.indication - Signal the called party
CONNECT.response - Callee accept/rejects calls & confirms or counter proposes message sizes for example.
CONNECT.confirm - Tell the caller whether the call was accepted
DATA.request - Request that data be sent
DATA.indication - signal that data arrived
DISCONNECT.request - request that connection be released
DISCONNECT.indication - signal the peer about the request
Network software/Service primitives