Whether deploying a new VxRail or deploying a new cluster you will still need a way for the virtual machines to communicate. With VxRail manager it will create a virtual distributed switch (vDS) as part of the initial deployment leveraging the first four onboard ports. However, if you are leveraging an additional daughter card for VM traffic then you will still need to create a vDS.
What is a Virtual Distributed Switch
vDS is single virtual switch across all associated ESXi hosts and allows virtual machines to maintain consistent network configuration as they migrate across multiple hosts. Distributed switches forward frames at layer 2, support VLANs, NIC teaming, outbound traffic shaping, etc.
Uplink port group
An uplink port group or dvuplink port group is defined during the creation of the distributed switch and can have one or more uplinks. An uplink is a template that you use to configure physical connections of hosts as well as failover and load balancing policies. You map physical NICs of hosts to uplinks on the distributed switch. At the host level, each physical NIC is connected to an uplink port with a particular ID. You set failover and load balancing policies over uplinks and the policies are automatically propagated to the host proxy switches, or the data plane. In this way you can apply consistent failover and load balancing configuration for the physical NICs of all hosts that are associated with the distributed switch.
Distributed port group
Distributed port groups provide network connectivity to virtual machines and accommodate VMkernel traffic. You identify each distributed port group by using a network label, which must be unique to the current data center. You configure NIC teaming, failover, load balancing, VLAN, security, traffic shaping , and other policies on distributed port groups. The virtual ports that are connected to a distributed port group share the same properties that are configured to the distributed port group. As with uplink port groups, the configuration that you set on distributed port groups on vCenter Server (the management plane) is automatically propagated to all hosts on the distributed switch through their host proxy switches (the data plane). In this way you can configure a group of virtual machines to share the same networking configuration by associating the virtual machines to the same distributed port group.
Creating the vDS
Now we must add the hosts to the vDS
Create vDS Port Group
Setting up a new vDS is pretty simple and straight forward. In environments not leveraging NSX they are pretty handy. In VxRail manager it automatically creates your first vDS leveraging the first four onboard ports. However, if you want to add a vDS for a daughter card for additional VM traffic then creating a new vDS is the way to go.