Introduction to Networking for NonStop S-Series Servers

Expand Network
Introduction to Networking for HP NonStop S-Series Servers
—520670-005
5-4
Multiple Communications Environments
Multinode process communications is the same as single-server process
communications, with the following exceptions:
•
The Expand subsystem redirects the file-system request to a hardware
communications device.
•
A communications line rather than the ServerNet SAN carries the message to the
remote process.
Multiple Communications Environments
Nodes in an Expand network can be connected using a variety of data communications
technologies and protocols. A single network can consist of any combination of these
different data communications methods.
Nodes in an Expand network can be connected by
•
Full-duplex leased lines or satellite connections using the High-Level Data Link
Control (HDLC) protocol
•
X.25 virtual-circuit connections to a packet-switched data network (PSDN)
•
Connections to IBM Systems Network Architecture (SNA) networks
•
Local area network (LAN) or wide area network (WAN) connections to networks
that use the Internet Protocol (IP)
•
Local area network (LAN) or wide area network (WAN) connections to
Asynchronous Transfer Mode (ATM) networks
•
Multimode fiber-optic cables (FOX rings)
•
Single-mode fiber-optic cables (ServerNet clusters)
Leased and Satellite Connections
You can connect Expand nodes with leased or satellite lines using either the HDLC
Normal protocol or the HDLC Extended Mode protocol.
•
The HDLC Normal protocol is provided for use with conventional voice-grade
leased-line and switched-line facilities.
•
The HDLC Extended Mode protocol is a satellite-efficient version of HDLC and is
provided for use with satellite connections.
Note. Incoming and outgoing messages usually bypass the Expand line-handler process and
are handled directly by the ServerNet fabrics and the ServerNet/Fiber eXtension (Server-
Net/FX) adapters when servers are connected by fiber-optic cables in a FOX ring. FOX rings
are explained in Fiber-Optic Cables on page 5-5.
Note. There is no automatic dialing function within the Expand subsystem for dial-up lines.