IBM AIX HACMP SG24-5131-00, Hardware User Manual

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Cluster Planning
11
2.2 Cluster Networks
HACMP differentiates between two major types of networks: TCP/IP networks
and non-TCP/IP networks. HACMP utilizes both of them for exchanging
heartbeats. HACMP uses these heartbeats to diagnose failures in the cluster.
Non-TCP/IP networks are used to distinguish an actual hardware failure from
the failure of the TCP/IP software. If there were only TCP/IP networks being
used, and the TCP/IP software failed, causing heartbeats to stop, HACMP
could falsely diagnose a node failure when the node was really still
functioning. Since a non-TCP/IP network would continue working in this
event, the correct diagnosis could be made by HACMP. In general, all
networks are also used for verification, synchronization, communication and
triggering events between nodes. Of course, TCP/IP networks are used for
communication with client machines as well.
At the time of publication, the HACMP/ES Version 4.3 product does not use
non-TCP/IP networks for node-to-node communications in triggering,
synchronizing, and executing event reactions. This can be an issue if you are
configuring a cluster with only one TCP/IP network. This limitation of
HACMP/ES is planned to be removed in a future release. You would be
advised to check on the status of this issue if you are planning a new
installation, and to plan your cluster networks accordingly.
2.2.1 TCP/IP Networks
The following sections describe supported TCP/IP network types and network
considerations.
2.2.1.1 Supported TCP/IP Network Types
Basically every adapter that is capable of running the TCP/IP protocol is a
supported HACMP network type. There are some special considerations for
certain types of adapters however. The following gives a brief overview on the
supported adapters and their special considerations.
Below is a list of TCP/IP network types as you will find them at the
configuration time of an adapter for HACMP. You will find the non-TCP/IP
network types in 2.2.2.1, “Supported Non-TCP/IP Network Types” on page
14.
• Generic IP
• ATM
• Ethernet
• FCS