At the time of initial cluster build, you have flexibility in how you want to assign uplinks to the VxRail networks. You can deploy VxRail using the predefined uplink assignment templates, or you can select which uplinks on each node you want to assign to a given VxRail network. A VxRail cluster where the networking profile is predefined follows prescriptive rules for node port selection, and the assignment of the node ports to VxRail networks. With a custom profile, you can direct VxRail to follow a rule set you define for port selection and determine which node ports are selected to support VxRail networking, and which uplinks are assigned to a specific VxRail network. 

• If you opt to deploy VxRail with a predefined network profile, each VxRail node port used to support VxRail networking must be running at the same speed.
• If you choose to create a custom profile option, the following general rules are applicable:

• The VxRail nodes can be configured with Ethernet ports running at different speeds. For instance, you can have 10 GbE ports on the NDC/OCP, and 25 GbE ports on a PCIe adapter card.
• The Ethernet ports that you select to support a VxRail network must be configured at the same speed. For instance, you can assign 10 GbE ports to the VxRail management networks, and 25 GbE ports to VxRail nonmanagement networks such as vSAN and vMotion.
• The Ethernet ports that you select to support a VxRail network must be of the same type. For instance, you cannot assign an RJ45 port and an SFP+ port to support the same VxRail network.

If the VxRail cluster is deployed using one of the fixed network profiles, the uplink assignments to each VxRail network are predefined based on whether two ports, or four ports are selected to support the VxRail cluster. The fixed network profiles only select NDC/OCP-based ports for VxRail networking purposes.

• In a 2-port configuration, the VxRail networks share the two uplinks.
• In a 4-port configuration, the management networks are assigned two uplinks and the vMotion and vSAN networks are assigned the other two uplinks.

Figure 45.    Default network profiles for a 2-port and a 4-port VxRail network

If you plan to use both NDC/OCP-based and PCIe-based ports to enable NIC redundancy and eliminate the NDC/OCP as a single point of failure, you can customize which ports on the VxRail nodes you want to use for each VxRail network. For example, you can select one port from the NDC/OCP and one port from a PCIe adapter card running at the same speed, and assign both of those ports to support the VxRail management networks. You can then select another port on the NDC/OCP, and another compatible port on the PCIe adapter card, and assign those to the nonmanagement VxRail networks. 

Figure 46.    Custom uplink assignment across NDC/OCP-based and PCIe-based ports

If you expect the applications to be running on the VxRail cluster to be I/O intensive and require high bandwidth, you can place the vMotion network on the same pair of ports as reserved for the VxRail management networks, and isolate the vSAN network on a pair of Ethernet ports.

Figure 47.    Custom uplink assignment with vSAN network isolated on two Ethernet ports

The decision that you make on customizing the uplink assignments can have an impact on the top-of-rack switch configuration.

• With a custom uplink assignment, there is more flexibility in a data center with a mixed network. You can assign the resource-intense networks like vSAN to higher-speed uplinks, and low-impact networks to slower uplinks, and then connect those uplinks to switches with compatible port speeds.
• On VxRail nodes with both NDC/OCP ports and PCIe Ethernet adapter cards, you can migrate certain VxRail networks off the NDC/OCP ports and onto PCIe ports after the cluster is built. This is advantageous if workload demand increases on the cluster, and additional bandwidth is required. You can later install switches that better align with adapting requirements and migrate specific workloads to those switches.