What you need to know
Which traffic direction should a bandwidth limit constrain on an SDN VM network adapter?
Potentially affected
Administrators applying SDN QoS to virtual-machine network adapters.
DSE recommendation
Ask the workload owner to specify whether the concern is outbound traffic, inbound traffic, or both.
Source facts
Microsoft SDN QoS permits a maximum bandwidth limit on VM traffic in the sending direction, receiving direction, or both. The documented control applies to VMs on traditional VLANs and SDN virtual networks. Microsoft configures the policies through Network Controller PowerShell cmdlets after Network Controller is installed. The source also describes hardware QoS offload for physical adapters that support it. Microsoft documentation.
Applicability
Identify the VM adapter, network attachment, direction of the contested traffic, and application requirement. Review the physical adapter capabilities and host configuration separately from choosing the requested limit.
DSE recommendation
Ask the workload owner to specify whether the concern is outbound traffic, inbound traffic, or both. Record separate limits and the reason for each. Choose a controlled competing workload and retain the original policy association before changing the adapter configuration.
Verification
Measure both send and receive traffic during the approved test, including a competing VM. Compare the observed rates and application response with the chosen directional limits. Inspect the policy attachment on the intended adapter and preserve any unexpected restriction in the opposite direction as an issue to resolve before wider deployment.
Official references
Microsoft Learn: Configure Quality of Service (QoS) for a VM network adapter. Source reviewed September 8, 2026.
Review the official source
Configure Quality of Service (QoS) for a VM network adapter · Verified September 8, 2026
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