Sena HelloDevice Pro PS110 Series User Manual page 47

Cyclic Connection
If Cyclic Connection function is enabled, the Pro Series will make an attempt to connect to the
user-defined remote host(s) at a given interval even if there' s no incoming serial data from the
device connected to that serial port. If there is data on the remote host(s) to be sent to serial
device, it can be transferred to the serial device via Pro Series'serial port after the connection is
established. Eventually, users can monitor the serial device periodically by making the remote
host send the serial command to the Pro Series whenever it is connected to the remote host. This
option is useful when users need to gather the device information periodically even if the serial
device does not send its data periodically. Figure 4-5 shows the State Transition Diagram of the
session operations in TCP mode.
Socket ID
When many Pro Series devices connects a same remote host(s), sometimes it is needed to
identify the device. In this case, Socket ID is available for identification of each device. Pro Series
send the Socket ID string before starting the data transmission. User can define Socket ID with a
specific string. In TCP mode, specified Socket ID strings are sent once at the time of establishing
TCP connection.
TCP Nagle algorithm
Modern TCP implementations include a mechanism, known as the Nagle algorithm, which
prevents the unnecessary transmission of a large number of small packets. This algorithm has
proved useful in protecting the Internet against excessive packet loads. However, some
applications suffer performance problems as a result of the traditional implementation of the Nagle
algorithm.(An interaction between the Nagle algorithm and TCP' s delayed acknowledgement
policy can create especially severe problems, through a temporary "deadlock.") TCP Nagle
algorithm can be disabled or enabled through this option.
Inactivity Timeout
When Inactivity Timeout function is enabled, connection between remote host(s) and Pro Series
will be closed automatically if there is no data transmission during the value which is set in
Inactivity Timeout configuration.
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