VMware vSphere 5.5 Cookbook

Migrating a virtual machine network from a vSphere Standard Switch to a vSphere Distributed Switch

Once you have a VDS set up with ESXi hosts added to it, the next most common step is to migrate the virtual machine network on to the dvPortGroup on the VDS.

Getting ready

To ensure that the virtual machines do not lose network connectivity when they are migrated to a VDS, verify that at least one or more physical adapters backing the virtual machine network have already been mapped to an uplink on the VDS and is an active uplink on the destination dvPortGroup. Refer to the Mapping a physical adapter (vmnic) to a dvUplink recipe for instructions on how to do this.

Also make sure that the dvPortGroup is configured with the same VLAN, MTU, and link aggregation ...