IBM SG24-5131-00 Benutzerhandbuch

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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