A VMkernel networking interface is used for VMware vMotion, IP storage, and Fault Tolerance.

In ESXi, the VMkernel networking interface provides network connectivity for the ESXi host as well as handling vMotion and IP storage.

Moving a virtual machine from one host to another is called migration. Using vMotion, you can migrate powered on virtual machines with no downtime. Your VMkernel networking stack must be set up properly to accommodate vMotion.

IP storage refers to any form of storage that uses TCP/IP network communication as its foundation, which includes iSCSI, FCoE and NFS for ESXi. Because these storage types are network based, they can use the same VMkernel interface and port group.