Introduction to Networking for NonStop S-Series Servers

Communications Product Concepts and

Components

Introduction to Networking for HP NonStop S-Series Servers—520670-005

2-24

ServerNet Wide Area Network (SWAN) Concentrator

The SWAN concentrator is a communications device that connects bit-synchronous,

byte-synchronous, and asynchronous devices to NonStop S-Series servers. This

enables customers migrating from NonStop K-series to S-series servers to preserve

their investment in legacy devices.

A SWAN concentrator can be removed from or added to the Ethernet LAN pair without

interrupting the operation of other attached devices. This feature enables the online

replacement of SWAN concentrators and facilitates online expansion.

Each SWAN concentrator contains three communications line interface processors

(CLIPs) 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 SWAN line can support asynchronous, byte-synchronous, or bit-synchronous

transmissions independent of the other lines. This enables a single SWAN

concentrator to perform the functions of multiple controllers.

The SWAN concentrator connects to the NonStop S-Series server using fault-tolerant,

10Base-T Ethernet connections provided by one or two Ethernet 4 ServerNet adapters

(E4SAs). HP recommends that you configure the SWAN concentrator to connect to

Ethernet ports on two E4SAs; this type of configuration provides more fault-tolerance

for the IOPs that use the lines on the SWAN concentrator in the event of failure in one

of the paths to the SWAN concentrator.

The WAN subsystem is used to control access to the SWAN concentrator. The WAN

subsystem is described in Wide Area Network (WAN) Subsystem on page 2-14.

Note. The configuration rules allow any I/O protocol to share a CLIP with any other I/O

protocol. All combinations are fully supported.