Sun Cluster software uses the private network for internal communication between nodes. A Sun Cluster configuration requires at least two connections to the cluster interconnect on the private network. These connections are called the private interconnect.
You must connect all nodes to the private interconnect through at least two redundant physically independent networks, or paths, to avoid a single point of failure. You can have several physically independent networks between any two nodes.
The private interconnect consists of three hardware components that you add by using SunPlex Manager:
Private adapters are network interface cards that reside in each cluster node. Their names are constructed from a device name immediately followed by a physical-unit number (for example, qfe2). Some adapters have only one physical network connection. Other adapters, like the qfe card, have multiple physical connections. Some adapters also contain both network interfaces and storage interfaces.
Note: A network adapter with multiple interfaces could become a single point of failure if the entire adapter fails.
Junctions are the switches that reside outside of the cluster nodes. Junctions take care of pass-through and switching, allowing you to connect more than two nodes. In a two-node cluster, junctions are optional because the nodes can be directly connected to each other through redundant physical cables. These redundant cables are connected to redundant adapters on each node. Any configuration greater than two nodes requires junctions.
Cables are the physical connections that are placed either between two network adapters or between an adapter and a junction.