Dell PowerVault 775N (Rackmount NAS Appliance) - Manual (Page 68)

A network that carries internal cluster communication
A public network that provides client systems with access to cluster application services
A public-and-private network that carries both internal cluster communication and connects client systems to cluster
application services
Neither a public nor private network that carries traffic unrelated to cluster operation
Preventing Network Failure
MSCS uses all available private and public-and-private networks for internal communication. Configure multiple networks as
private or public-and-private to protect the cluster from a single network failure. If there is only one such network available
and it fails, the cluster nodes stop communicating with each other. When two nodes are unable to communicate, they are
partitioned and MSCS automatically shuts down on one node. While this shutdown guarantees the consistency of application
data and the cluster configuration, it can make cluster resources unavailable.
For example, if each node has only one network adapter, and the network cable on one of the nodes fails, each node,
(because it is unable to communicate with the other), attempts to take control of the quorum disk. There is no guarantee that
the node with a functioning network connection will gain control of the quorum disk. If the node with the failed network cable
gains control, the entire cluster is unavailable to network clients. To avoid this problem, ensure that all nodes have at least
two networks and are configured to use both networks for the private network (internal communications).
Node-to-Node Communication
MSCS does not use public only networks for internal communication. For example, a cluster has Network A configured as
private and Network B configured as public. If Network A fails, MSCS does not use Network B because it is public; the nodes
stop communicating and one node terminates its Cluster Service.
Network Interfaces
The Microsoft® Windows® operating system keeps track of all network adapters in a server cluster. This tracking system
allows you to view the state of all cluster network interfaces from a cluster management application, such as Cluster
Administrator.
Cluster Nodes
A cluster node is a system in a server cluster that has a working installation of the Windows operating system and MSCS.
Cluster nodes have the following characteristics:
Every node is attached to one or more cluster storage devices. Each cluster storage device attaches to one or more
disks. The disks store all of the cluster's configuration and resource data. Each disk can be owned by only one node at
any point in time, but ownership can be transferred between nodes. The result is that each node has access to all
cluster configuration data.
Every node communicates with the other nodes in the cluster through one or more network adapters that attach nodes
to networks.
Every node in the cluster is aware of another system joining or leaving the cluster.
Every node in the cluster is aware of the resources that are running on all nodes in the cluster.