Recommended ES dual controller NAS network architecture
Below is the picture to describe the recommended network architecture of ES1640dc dual controller NAS.

ES dual controller NAS places strong emphasis on high availability and failover, so network configuration is divided into two different use cases: "management" and "data transmission".
ES1640dc / ES1640dc v2 NAS has two controllers, each with a management port and two data ports. The management port is used to open the QES desktop to manage the NAS using a web browser, and the data port is used for data access (such as Samba, NFS, and iSCSI). To achieve complete failover deployment, it is recommended that the data port on each controller be connected to a different network switch and that the data ports on both sides of the controller be configured with static IP addresses.
For example, data port 1 of controller A should be set on the same subnet as data port 1 of controller B, and the same should be set for data port 2. As a result, when one controller fails, another controller will automatically take over. The server side can still connect to the controller that has taken over through the original IP address, so that the previous ongoing data access is continued.