A. There's no specific encryption used for CSV traffic, but if you've implemented IPSEC, IPSEC encryption is used for CSV data and all other intra-cluster communication.

See also:
How do I create a failover cluster in Windows Server 2008?
Is a Windows Server 2003 and Windows Server 2008 mixed-cluster possible?
How can I add disk resources to a Windows Server 2008 cluster from the command line?
How do cluster shared volumes work in Windows Server 2008 R2?

Videos:
How to Manage Failover Clusters in Windows Server 2008
Configure Windows Server 2008 Failover Clustering from the Command Line


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