When adding new nodes to an existing ONTAP cluster, proper cabling to the cluster interconnect switches is mandatory. The cluster interconnect network is a dedicated, private network used exclusively for internal cluster communication such as configuration synchronization, data movement, and quorum maintenance.

In AFF A400 systems, the cluster interconnect ports are fixed high-speed Ethernet ports that are clearly identified and reserved for cluster connectivity. These ports are typically 25GbE or 40GbE depending on configuration and are grouped together physically on the controller chassis.

Referring to the exhibit, the ports labeled with number 2 correspond to the cluster interconnect ports. These are the only ports that must be connected to the cluster interconnect switches when adding nodes to an existing cluster. ONTAP requires that each node have redundant connections to both cluster switches to maintain high availability and cluster quorum.

Ports labeled as other numbers in the exhibit represent different functions, such as management ports, data ports, or shelf connectivity ports, none of which are valid for cluster interconnect cabling.

NetApp installation procedures emphasize that incorrectly cabling non-cluster ports to cluster switches can prevent nodes from joining the cluster or cause cluster instability. Therefore, identifying and using the correct cluster interconnect ports is a critical installation step.

As shown in the exhibit, number 2 clearly identifies the correct ports used to cable the new AFF A400 nodes into the existing cluster interconnect infrastructure.