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3.2.1 TCP Server Mode Operations
The Rhio10 works as a TCP server, and the default TCP state is [Listen] in this mode. The
Rhio10 supports only one TCP socket connection. If a connection is currently established, the
additional connection requests will be rejected. The remote host will be a socket program acting
as a TCP client running on user ’PC.
1) Typical State Transition
[Listen] --> [Sync-Received] --> [Established] --> [Data] --> [Closed] --> [Listen]
At start -up, an initial TCP state is [Listen]. If there is any incoming TCP connection request, the
state will be changed into [Sync -Received], then [Established], which means a session is
opened. For a while, data will be transferred between the hosts. This is the [Data] state. The
session will be disconnected due to the request of one of them, which is [Closed] state. And
then, the state is automatically changed to its original state, [Listen].
2) Operations
I/O status data transfer
When a session has been established, the Rhio10 transfers the I/O status data to the IP
address of the remote host. If there’s no remote host connected to the Rhio10, all the incoming
I/O status data are discarded.
Session disconnection
The connected session will be disconnected when the remote host sends disconnection request
or when no I/O data transfer activity is found for a certain amount of time, which is “
Inactivity
timeout
”.
Figure 3-6 shows the State Transition Diagram of the session operations in
TCP server
mode.
