By default, a VI workload domain cluster uses a single vSphere Distributed Switch with two physical network cards. The switch design includes determining the traffic types on the switch, the number of required NICs, and MTU configuration.

This design uses the default switch configuration. VMware Cloud Foundation supports up to the vSphere maximum numbers for vSphere Distributed Switches. However, you can use the SDDC Manager API to tailor configurations according to your environment needs.

MTU value is set to 9000 bytes to improve traffic throughput with the least CPU power overhead.

Table 1. Default vSphere Distributed Switch Configuration

Property

Value

Number of vSphere Distributed Switches

1

Number of Physical NIC Ports

2

Network I/O Control

Enabled

MTU size

9000
Table 2. Physical Uplinks on the Default vSphere Distributed Switch

Physical NIC

Function

vmnic0

Uplink

vmnic1

Uplink
Table 3. Design Decisions for vSphere Distributed Switch

Design ID

Design Decision

Design Justification

Design Implication

VCF-WLD-VCS-VDS-001

Use a single vSphere Distributed Switch per vSphere cluster.

  • Reduces the complexity of the network design.

  • Reduces the size of the fault domain.

Increases the number of vSphere Distributed Switches that must be managed because you cannot share a distributed switch between clusters.

VCF-WLD-VCS-VDS-002

Configure the MTU size of the vSphere Distributed Switch to 9000 bytes for jumbo frames.

  • Supports the MTU size required by system traffic types.

  • Improves traffic throughput.

When adjusting the MTU packet size, you must also configure the entire network path (VMkernel ports, virtual switches, physical switches, and routers) to support the same MTU packet size.