Technical data

utility, the Librarian utility, the OpenVMS Debugger (also known as the symbolic
debugger), the Delta/XDelta Debugger, and run-time libraries. However, some
TCP/IP Services components are available only on OpenVMS Alpha, including:
• BIND Version 9
•IMAP
• PPP
These components are introduced later in this manual.
For details about the similarities and differences between the programming
environment on VAX and Alpha, refer to A Comparison of System Management on
OpenVMS AXP and OpenVMS VAX, which provides guidelines for developing
applications that run on both OpenVMS VAX and OpenVMS Alpha, as well as
additional guidelines for systems that run in a mixed-architecture OpenVMS
Cluster.
3.2 OpenVMS Cluster Configuration
Compaq TCP/IP Services for OpenVMS supports OpenVMS Cluster systems and
the use of cluster aliases. The network sees the cluster as one system with one
name, the cluster alias. A remote host can use the cluster alias to address the
cluster as one host, or it can use the host name of a cluster member to address a
clustermemberindividually.
In a DECnet network, it is convenient to be able to treat nodes within a
homogeneous OpenVMS Cluster as though they were a single node. You can do this
by establishing an alias node identifier for the cluster. You can specify the alias
node identifier as either a unique node address or a corresponding node name. Any
member node can elect to use this special node identifier as an alias while retaining
its own unique node identification. For more information on the use of the optional
cluster alias node identifier, refer to the DECnet for OpenVMS Networking Manual.
_________________________ Note _________________________
DECnet–Plus software is not required in an OpenVMS Cluster
configuration. However, DECnet–Plus is necessary if internode
process-to-process communication using DECnet mailboxes is
needed. For more information about DECnet-Plus in an OpenVMS
Cluster configuration, refer to the Guidelines for OpenVMS Cluster
Configurations manual.
For load balancing, an OpenVMS Cluster can consist entirely of OpenVMS Alpha
nodes or of a combination of OpenVMS VAX and OpenVMS Alpha nodes.
You can have numerous OpenVMS Cluster configurations. For complete
information about supported devices and configurations, refer to Guidelines for
OpenVMS Cluster Configurations and the OpenVMS Cluster Software Software
Product Description (SPD). For complete information about setting up and using an
OpenVMS Cluster environment, refer to the OpenVMS Cluster Systems manual.
3.2.1 Failover Capability
Failover capability is the hallmark of a cluster environment. If one computer , or
node, in the cluster fails, the others can assume its functionality and continue. This
is called automatic failover.
OpenVMS Server and Network Configurations 3–3