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A4-18
893-741-B
The Port Server and Rotaries
Terminal Server TTY (TSTTY)
TSTTY is a set of independent software modules that allow a host system to connect to Model 5390
serial ports in such a way that users appear as if they are directly connected to the host system. One
module runs in the Model 5390 server and one module runs in the host. A protocol links the two
modules together. When a host wants to talk to a device attached to a port that is in slave or adaptive
mode, it must first establish a connection by connecting to the appropriate TCP port on the Model
5390 server. The Model 5390 server and host can then send messages over this link to exchange
data and commands. (TSTTY runs on top of any reliable byte stream protocol, for example, TCP.)
By providing a standard tty interface to the host, all standard programs can access the ports through
standard serial port devices, and hence perform all of the functions that a standard, directly connected
port can perform.
Many of the standard actions, such as changing the serial port’s baud rate, are passed to the Model
5390 server for execution, while some actions, such as dealing with a Break character, are executed
by the host system. This design optimizes performance by allowing functions to be executed
wherever it is best to do so. Consequently, since all standard system programs can be run on TSTTY
ports, these ports can be used for login sessions (via getty or ttymon), as line printer ports using the
standard spooler connections, for uucp/cu connections to other systems, and for user written
programs.
TSTTY provides several advantages over telnet or rlogin:
•
Processes ioctl from a host to change the parameters of the remote port.
•
Eliminates the need for special handling required by many terminal servers.
•
Enables terminal servers to use standard UNIX utilities.
How TSTTY Interacts with Model 5390 Port Parameters
Because the TSTTY code on the Model 5390 server receives commands from the host to change
the settings of the serial port, there is a degree of unseen interaction between these settings and the
default settings for the port. This interaction is similar to that of the Model 5390 CLI command stty
and the port parameters, in that the settings are reset to their default values when the port is reset.
For TSTTY, a port is reset when the host closes the last session (usually there is only one session)
to the port.
Содержание 5390
Страница 28: ...893 741 B Figures xxviii ...
Страница 44: ...893 741 B Preface xliv ...
Страница 45: ......
Страница 48: ......
Страница 60: ...A1 12 893 741 B Introduction to the Model 5390 Server ...
Страница 106: ...A3 18 893 741 B Configuring Ports ...
Страница 142: ...A5 12 893 741 B Printers ...
Страница 152: ...A6 10 893 741 B Modems ...
Страница 168: ...A7 16 893 741 B Serial Line Internet Protocol SLIP ...
Страница 224: ...A9 38 893 741 B Internetwork Packet Exchange IPX Protocol ...
Страница 258: ...A11 12 893 741 B Dial up Networking ...
Страница 289: ...893 741 B A12 31 Internet Protocol IP Routing that are possible ...
Страница 506: ...A15 86 893 741 B Using Model 5390 Security ...
Страница 507: ......
Страница 508: ... Chapter B1 Network Administration Chapter B2 Simple Network Management Protocol SNMP Part B Network Administration ...
Страница 544: ...B1 36 893 741 B Network Administration ...
Страница 574: ...B2 30 893 741 B Simple Network Management Protocol SNMP ...
Страница 575: ......
Страница 606: ...C1 30 893 741 B na Commands ...
Страница 676: ...C2 70 893 741 B Configuration Parameters ...
Страница 772: ...C3 96 893 741 B Using the CLI Commands ...
Страница 794: ...C5 12 893 741 B Network Protocols ...
Страница 795: ......
Страница 796: ... Appendix D1 Software Reference Part D Appendixes ...