Envoy Application Programming Manual
Table Of Contents
- What’s New in This Manual
- About This Manual
- 1 Application Programming With Envoy
- 7 ADM-2 Multipoint Supervisor Protocol
- 8 TINET Multipoint Supervisor Protocol
- 9 Burroughs Point-To-Point Protocol
- 10 Asynchronous Line Supervisor Protocol
- A ASCII Character Set
- B ASCII to EBCDIC Code Conversion
- C File-System Procedures
- D Statistics Messages
- E S-Series Changes to Envoy
- NonStop™ Himalaya S-Series Server Architecture
- G-Series Migration Considerations
- CBSENSEON and CFSENSEON Modifiers
- LEOTRESYN and NOLEOTRESYN Modifiers
- Treatment of Characters After the Termination Character
- Number of SYN Characters
- DTR Drop
- Reporting of Parity Error
- Half-Duplex Support for Asynchronous Lines
- Controller Replacement
- SYSGEN and COUP
- Unit Numbers
- FDX Line Changes
- No Support for Auto-Call Unit
- Glossary
- Index
TINET Multipoint Supervisor Protocol
Envoy Application Programming Manual—427159-001
8-4
TINET Multipoint Supervisor Selection
TINET Multipoint Supervisor Selection
The supervisor station selects a terminal by calling the WRITE procedure. The call also
writes the message to the selected terminal. Figure 8-2 shows the TINET multipoint
supervisor selection sequence.
Retries
Operations are subject to transmission errors such as longitudinal redundancy check
(LRC) errors, nonresponding terminals, and incorrect responses from terminals. When
these types of errors are encountered, Envoy, on behalf of the application process, retries
the requested operation. Note, however, that not all operations are retried.
To specify the maximum number of times Envoy retries an operation encountering an
error indication, a retry count value is specified for each communications line when
issuing the ADD DEVICE command. You can alter the retry count value by calling the
SETMODE procedure. If an error condition persists after the operation has been retried
the specified number of times, an error indication is returned to the application process
that requested the operation.
Timeouts
The protocol uses timeouts to detect error conditions. You specify a timeout value for
each line when issuing the ADD DEVICE command. You can subsequently alter the
value by calling the SETMODE procedure. Table 8-2 summarizes the effect of the
timeout value during the WRITE and READ procedures. An operation that times-out is
not retried.
Figure 8-2. TINET Multipoint Supervisor Selection
043CDT .CDD
2
Send Data to
Terminal
1
Format Message
CALL WRITE...