7–4
MULTINET4 MULTI-PORT SERIAL SERVER & MANAGED SWITCH – INSTRUCTION MANUAL
TERMINAL SERVER APPLICATION NOTES
CHAPTER 7: TERMINAL SERVER APPLICATION NOTES
7.3
Terminal Server Operation
The Multinet4 offers a terminal server function that transports serial characters over a
TCP/IP network. A flexible set of connection options allows the user to configure each serial
port for a different mode of operation. The terminal server functionality is organized into
serial communication channels that may be added or deleted from the system. Each
channel is associated with a particular serial port and operates either in passive or active
mode.
7.3.1
Passive Mode Channels
When a terminal server channel operates in passive (server) mode, it waits for incoming
TCP connection requests. When a request is received it is accepted if the following criteria
are met:
• serial port operational state is UP
• maximum number of incoming connections will not be exceeded
After a connection request is accepted, the TCP connection becomes active and serial data
may be transmitted and received on the channel.
A terminal server channel operates in passive mode if the
“Call Direction”
parameter is set
to “
IN
."
The following configuration parameters also affect the operation of the port in passive
mode:
•
Local IP
– the IP address at which the server listens for connections. If the system
has only a single assigned IP address, this parameter defaults to the system IP
address and cannot be changed. If the system has multiple assigned IP addresses,
this parameter can be set to any of those addresses. In this case, the software will
only accept connections destined for the configured IP address. The port will not
be reachable using other IP addresses, even if they are assigned to the system.
•
Local TCP
– the TCP port at which the server listens for connections. The TCP port
may be in the range 1000 to 65535. It is invalid to assign the same TCP port to
multiple terminal server serial ports.
•
Maximum Connections
– the maximum number of incoming connections that will
be accepted for the terminal server serial port. Up to 5 simultaneous incoming
connections are supported per serial port.
7.3.2
Active Mode Channels
When a terminal server port operates in active (client) mode, it actively attempts to
connect to a specified remote host whenever the serial port operational state is UP.
After an outgoing connection request is accepted by the remote host, the TCP connection
becomes active and serial data may be transmitted and received on the channel.
A terminal server port operates in active mode if the
“Call Direction”
parameter is set to
“
OUT
".
