Expand Configuration and Management Manual (G06.24+)

Expand Overview
Expand Configuration and Management Manual—523347-008
2-5
Multiple Communications Environments
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
•
Multi-mode 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
(ServerNet/FX) adapters when servers are connected by fiber-optic cables in a FOX ring. FOX
rings are explained in Fiber-Optic Cables on page 2-6.
Note. There is no automatic dialing function within the Expand subsystem for dial-up lines.