Explanation/Reference:
Explanation:
http://technet.microsoft.com/en-us/library/dn440540.aspx
Protect against short-term network interruptions
Failover cluster nodes use the network to send heartbeat packets to other nodes of the cluster.
If a node does not receive a response from another node for a specified period of time, the cluster removes the node from cluster membership.
By default, a guest cluster node is considered down if it does not respond within 5 seconds.
Other nodes that are members of the cluster will take over any clustered roles that were running on the removed node.
Typically, during the live migration of a virtual machine there is a fast final transition when the virtual machine is stopped on the source node and is running on the destination node.
However, if something causes the final transition to take longer than the configured heartbeat threshold settings, the guest cluster considers the node to be down even though the live migration eventually succeeds.
If the live migration final transition is completed within the TCP time-out interval (typically around 20 seconds), clients that are connected through the network to the virtual machine seamlessly reconnect.
To make the cluster heartbeat time-out more consistent with the TCP time-out interval, you can change the SameSubnetThreshold and CrossSubnetThreshold cluster properties from the default of 5 seconds to 20 seconds.
By default, the cluster sends a heartbeat every 1 second. The threshold specifies how many heartbeats to miss in succession before the cluster considers the cluster node to be down.