A VMkernel port group is created when there is a need to create a VMkernel network interface (VMK). It is used for management, FT, iSCSI, NAS, vMotion, and vSphere replication.
There can only be one VMkernel port per subnet. Although it doesn't stop you from creating multiple VMkernel ports per subnet, it will only use one of them. Usually, the VMkernel port that was first created is used. VMkernel traffic can be routed, although this is not advisable for vMotion, as it can cause latency issues. The VMkernel gateway IP address should also be in the same subnet.
Only one VMkernel default gateway can be configured on an ESXi host.
A VMkernel port group can be created either from ...