Telnet/iX Server Functionality Details [ COMMUNICATOR 3000 MPE/iX Release 5.5 (Non-Platform Software Release C.55.00) ]
COMMUNICATOR 3000 MPE/iX Release 5.5 (Non-Platform Software Release C.55.00)
Telnet/iX Server Functionality Details
by Lyn Hirsch and Cas Caswell
Commercial Systems Division
Introduction
This article provides more detailed information about the Telnet/iX
Server functionality introduced in the article, "Introducing the
Telnet/iX Server," in Chapter 8, "Networking/Client-Server." This
information applies to application managers/developers and end-users.
The Telnet/iX Server is available in two parts:
* With the MPE/iX 5.5 Release, the Telnet/iX Server will allow a
user to logon to the HP 3000 and use all MPE/iX CI commands, as
well as issue some Telnet client commands to the Server, which are
described in the "Telnet Client Commands Support" section later on
in this article.
* Full functionality, as documented for the Telnet/iX Server product
in the 5.5 version of the following manuals, will be available in
the Fall 1996:
* HP Telnet/iX User's Guide (36957-90154)
* Configuring and Managing MPE/iX Internet Services
(32650-90835)
* Asynchronous Serial Communications Programmer's Reference
Manual (32022-61001)
The following information describes the restricted functionality that is
available with this software.
FCONTROLs and FDEVICECONTROLs Support
The chart below shows the list of currently supported FControls (FC) and
FDevicecontrols (FDC) on a Telnet/iX session. Applications that depend
on functionality provided by FC or FDC intrinsics which are not listed on
this chart, may not work properly.
-------------------------------------------------------------------------------------------
| |
| FDC FC Description |
| |
-------------------------------------------------------------------------------------------
| |
| 4 12,13 Set echo at a terminal |
| |
| 14 34,35 Set line deletion response |
| |
| 30,32 N/A Define read trigger character |
| |
| 36 N/A Define backspace character |
| |
| 41 N/A Define subsystem break character |
| |
| 55 N/A Set backspace response action |
| |
| 57 N/A Obtain subsystem break character |
| |
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\ \ \ Important Details \ Please Read
* Note that since Fcontrols
4, 20, 21, 22 and FDC 2, 7,
8 are not on the supported
list, both the MPE logon
and password prompts will
not time out.
* VPLUS and user block modes
and binary mode are not
supported at this time.
* Typeahead is not supported.
All data entered before a
read has been posted,
including the events break
, subsystem break , XON,
and XOFF, will be
discarded.
Flow Control of Screen Display
When an application is sending large amounts of data to the screen, you
can pause the display to take note of a particular line. To do this on
most terminal emulators, use the STOP key to introduce a local flow
control. That is, the terminal emulator stops displaying data to the
screen, but does not communicate the stop to the Telnet/iX Server system.
NOTE Using the MPE traditional key strokes of CTRL-S, XOFF, and CTRL-Q,
XON, will not work. The Telnet/iX Server driver will either
discard the flow control characters, if no read is posted, or pass
the flow control characters to the user's application as data if
there is a read posted. In either case, the flow control
characters will not be interpreted in the manner the user intended.
BREAK Key on a Keyboard
If you type BREAK using the BREAK key from a keyboard, the Telnet/iX
Server driver may not recognize the break event. It depends on what the
Telnet client maps the BREAK to.
For example, one Telnet client maps the BREAK key to a NULL character and
sends it to the Telnet/iX Server. Since the NULL character on its own
has no meaning in the Telnet protocol, the NULL is passed to the
application as data and not recognized by the Telnet/iX Server as a break
event.
To generate a break event from a Telnet client, you can do one of the
following:
1. Use the send break command from the Telnet client.
2. Use the defined value for the quit variable from the Telnet
client. You can find out the value for the quit variable by using
the display command at the Telnet client prompt (the default value
for the quit variable on HPUX is ^\). Note that this is not the
same quit as the Telnet client quit command. The client must be
recognizing control characters for this to work.
For example, from an MPE session established with Telnet from an
HPUX system:
_________________________________________________________________________
| |
| |
| : ^] To get to the Telnet prompt. |
| |
| telnet> toggle localchars |
| Will recognize certain control characters. |
| |
| <CR> Press Carriage Return for the prompt. |
| |
| : |
| |
| |
_________________________________________________________________________
From this point on, typing the value for the quit variable from
the Telnet client (e.g., ^\) causes a Telnet send break command to
be sent to the Telnet/iX Server.
3. Some Telnet clients allow you to configure what the BREAK key will
send to the Telnet server. Using the Telnet/iX Server, configure
the client to send the Telnet command send break, when the user
presses the BREAK key.
Telnet Client Commands Support
A user may enter the user interface portion of their client to use some
of the commands provided there. These user interface commands will fall
into two families:
* The first family of commands are those that are purely local to
the client, such as display or status.
The Telnet/iX Server is not aware of the first family of commands
and will not be affected by them.
* The second family of commands are those that will communicate with
the Telnet/iX Server, such as open or close. However, not all of
the second family of commands are supported at this time,
particularly the toggle option commands.
The commands that are supported are:
open
send break
send AYT
send IP
send EC
send EL
quit
close
It is important to remember the following translations that will occur
with the Telnet/iX Server:
send IP Mapped to subsystem break on MPE.
send break Mapped to system break on MPE.
send EC Mapped to the currently defined backspace character.
send EL Mapped to line delete.
Maximum Number of Concurrent Sessions
The current maximum number of concurrent sessions using the Telnet/iX
Server to connect to an MPE host is 250.
TLNETDOC.ARPA.SYS
The file TLNETDOC.ARPA.SYS has not yet been updated with information for
the Telnet/iX Server.