- Fact:
- Protocols are commonly described using a state transition diagram
- This webnote will be a brief introduction on this subject
- A state transistion diagram
consists of:
- States that
are represented
by labeled nodes
- Transistions that are
represented by
edges from
a starting state to
an ending state
- The edges are labeled with an (event, response) pair
- States that
are represented
by labeled nodes
-
Example of a
state transition diagram:
- A more
concrete example:
- The edges
contains labels of the
form:
event ------------------ responseMeaning:
- Event =
the triggering event that
causes the
transition from
the starting state to
the ending state
- Response =
the action that will
take place when
the transition is
made
- A response will usually can another event to occur
- Event =
the triggering event that
causes the
transition from
the starting state to
the ending state
- Reading
a state transition diagram:
How to read the diagram:
- When in
the process is
in state 1:
- If event A
occurs, then:
- The process will issue the response B and
- Make the transition to state 2
- If event C
occurs, then:
- The process will issue the response D and
- Make the transition to state 3
- If event A
occurs, then:
- When in
the process is
in state 1:
- This diagram should
be clear: