Envoy ACP/XF Configuration and Management Manual

Introduction to EnvoyACP/XF
EnvoyACP/XF Configuration and Management Manual—429232-003
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The Architecture of NonStop S-Series Servers and
Integrity NonStop NS-Series Servers
simultaneously in both directions whenever appropriate. EnvoyACP/XF supports both
two-way alternate and two-way simultaneous transmission.
The Architecture of NonStop S-Series Servers
and Integrity NonStop NS-Series Servers
This subsection describes the EnvoyACP/XF subsystem relationship to some of the
other components of NonStop S-series servers and Integrity NonStop NS-series
servers.
Subsystems such as EnvoyACP/XF use a single data-communications ServerNet wide
area network (SWAN) concentrator rather than the communications controllers used by
D-series RVUs. The SWAN concentrator connects bit-synchronous, byte-synchronous,
and asynchronous devices to NonStop S-series servers and Integrity NonStop
NS-series servers (EnvoyACP/XF supports bit-synchronous data communication).
Each SWAN line can support these transmissions independent of the other lines. This
arrangement enables a single SWAN concentrator to perform the functions of multiple
controllers. Thus, customers migrating from NonStop K-series servers to NonStop S-
series servers or Integrity NonStop NS-series servers can preserve their investment in
legacy devices.
The SWAN concentrator connects to the NonStop S-series server or Integrity NonStop
NS-series server through dual 10Base-T Ethernet connections, which provide fault
tolerance if an Ethernet link or controller fails.
The SWAN concentrator replaces the 3604, 3605, and 6100 series of controllers.
EnvoyACP/XF communicates with the SWAN concentrator to a data link control (DLC)
task which runs in the SWAN concentrator.
EnvoyACP/XF has two DLC objects: C8169P00 for the RS232/RS449 interface and
C8169P20 for the X.21 interface. Two separate drivers, one for each interface, provide
an interface to the WAN ports on the CLIP (communications line interface processor).
The BIT driver is used for the RS232/RS449 interface and the X.21 driver is used for
the X.21 interface.