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
Software Concepts
Envoy Application Programming Manual—427159-001
2-2
The Envoy Environment
Each SWAN line can support these transmissions independent of the other lines. This
enables a single SWAN concentrator to perform the functions of multiple controllers.
Thus, customers migrating from Compaq NonStop ™ Himalaya K-series to S-series
servers can preserve their investment in legacy devices.
Envoy accesses the SWAN concentrator through Compaq NonStop™ TCP/IP and the
ServerNet LAN Systems Access (SLSA) subsystems. The SWAN concentrator connects
to the NonStop™ Himalaya S-series server through dual 10Base-T Ethernet
connections, which provide fault tolerance if an Ethernet link or controller fails.
The SWAN concentrator replaces the 3602 byte-synchronous and the 3603
asynchronous controllers. Envoy communicates with the SWAN concentrator to a data
link control (DLC) task which runs in the SWAN concentrator.
There are two DLC tasks: WANENVBSC and WANENVASC. The WANENVBSC
DLC task uses the WAN byte driver, emulating the 3602 controller for NonStop™
Himalaya K-series systems, and the WANENVASC DLC task uses the WAN ASYNC
driver, emulating the 3603 controller for NonStop™ Himalaya K-series systems. The
WAN driver provides an interface to the WAN ports on the CLIP (communications line
interface processor).
The CLIP is the major programmable device within the SWAN concentrator, providing
link-level protocol and a software interface to the server. The CLIP stores and
implements specific communications protocols. There are three CLIPs on one SWAN
concentrator and each CLIP supports two serial ports. The resulting six lines can support
any combination of the following interfaces:
•
RS-232
•
RS-449
•
V. 35
•
X.21
Each CLIP contains a Motorola MC68EN360 quad integrated communications
controller (QUICC) chip. Each CLIP interfaces to both the A and B Ethernet ports and
has two WAN ports.
The configuration rules enable any I/O protocol to share a CLIP with any other I/O
protocol; all combinations are fully supported.
The Envoy Environment
In a configured asynchronous or byte-synchronous data-communication environment,
Envoy consists of:
•
One or more protocol procedures
•
One or two driver procedures
•
One or more Envoy NonStop™ I/O process pairs
•
The default Envoy interrupt handler and/or one or more special interrupt handlers