Envoy Configuration and Management Manual

Introduction to Envoy
Envoy Configuration and Management Manual—429861-001
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Envoy Communications Interface
Envoy Communications Interface
The Envoy subsystem provides a data-link-level interface between transaction-oriented
applications and data communications networks that use byte-synchronous or
asynchronous communications lines. Using Envoy, you can establish data links between
your Compaq system and a variety of remote computers and terminals (Figure 2-1
).
NonStop Himalaya S-Series Server Architecture
Subsystems running in the NonStop Kernel, such as Envoy, use a single data-
communications ServerNet wide area network (SWAN) concentrator rather than the
communications controllers used by D-series. The SWAN concentrator connects bit-
synchronous, byte-synchronous, and asynchronous devices to Compaq NonStop
Himalaya S-series servers.
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.
Figure 2-1. Communications Interface
003CDT .CDD
ATM
Byte-Synchronous
Terminals
Other System
Compaq
System
Asynchronous
Terminals