A FlexCache volume in a Cloud Volumes ONTAP instance caching data from an on-premises cluster constitutes a relationship between two separate and distinct ONTAP clusters. Communication for data services between different clusters, such as replication or caching, is facilitated through a cluster peer relationship. This peering relationship exclusively uses the Intercluster network and its associated logical interfaces (LIFs) to establish the data path. Therefore, the Intercluster network must be configured and reachable between the on-premises cluster and the Cloud Volumes ONTAP instance for FlexCache to function.

B. Node Management: This network is used for administrative access to individual cluster nodes, not for data path traffic between clusters.

C. IntraCluster: This network facilitates high-speed communication within a single cluster (between its nodes), not between two different clusters.

D. Cluster Management: This network provides a single management interface for the entire cluster and is not used for data path services like FlexCache.

1. NetApp ONTAP 9 Documentation, FlexCache volume management overview: "FlexCache volumes communicate with their origin volumes over the intercluster network. You must set up a cluster peer relationship between the source and destination clusters." (Found under the Data protection and disaster recovery section).

2. NetApp Technical Report TR-4743, FlexCache in ONTAP: Section 3.3, "FlexCache Networking," states, "FlexCache uses the ONTAP cluster peering infrastructure to communicate between the caching cluster and the origin cluster. Therefore, the intercluster network must be configured on both clusters."

3. NetApp ONTAP 9 Cluster and Vserver Peering Express Guide: Section "Before you begin," states, "You must have configured intercluster LIFs on each node of both clusters... The intercluster LIFs are used for communication between the clusters." This guide details the foundational requirement for any inter-cluster communication, including FlexCache.