Each cluster in the management domain uses a single vSphere Distributed Switch whose design includes traffic types on the switch, the number of required NICs, and MTU configuration.

Table 1. sfo-m01-cl01-vds01 vSphere Distributed Switch Configuration

Number of Physical NIC Ports

Network I/O Control

MTU Size

2

Enabled

9000

Table 2. Physical Uplinks on sfo-m01-cl01-vds01 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

SDDC-MGMT-VI-NET-003

Enable Network I/O Control on vSphere distributed switch of the management domain cluster.

Increases resiliency and performance of the network.

If configured incorrectly, Network I/O Control might impact network performance for critical traffic types.

SDDC-MGMT-VI-NET-004

Configure the MTU size of the vSphere Distributed Switch to 9000 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.

vSphere Distributed Switch Health Check Design

The health check service helps identify and troubleshoot configuration errors in vSphere distributed switches.

  • Mismatching VLAN trunks between an ESXi host and the physical switches it's connected to.

  • Mismatching MTU settings between physical network adapters, distributed switches, and physical switch ports.

  • Mismatching virtual switch teaming policies for the physical switch port-channel settings.

Health check monitors VLAN, MTU, and teaming policies. Health check is limited to the access switch port to which the NICs of the ESXi hosts are connected.

Table 4. Health Check in vSphere Distributed Switch

Monitored Parameter

Description

VLANs

Checks whether the VLAN settings on the distributed switch match the trunk port configuration on the connected physical switch ports.

MTU

For each VLAN, determines whether the MTU size configuration for jumbo frames on the physical access switch port matches the distributed switch MTU setting.

Teaming policies

Determines whether the connected access ports of the physical switch that participate in an EtherChannel are paired with distributed ports whose teaming policy is Route based on IP hash.

Table 5. Design Decisions for vSphere Distributed Switch Health Check

Design ID

Design Decision

Design Justification

Design Implication

SDDC-MGMT-VI-NET-005

Enable vSphere Distributed Switch Health Check on all distributed switches.

vSphere Distributed Switch Health Check verifies that all VLANS are trunked to all ESXi hosts attached to the vSphere Distributed Switch and the MTU sizes match the physical network.

  • In a multiple availability zone configuration, some VLANs are not available to all ESXi hosts in the cluster which triggers alarms.

  • You must have a minimum of two physical uplinks to use this feature.