Use the Network I/O Control (NIOC) profile to allocate the network bandwidth to business-critical applications and to resolve situations where several types of traffic compete for common resources.

NIOC profile introduces a mechanism to reserve bandwidth for the system traffic based on the capacity of the physical adapters on a host. Version 3 of the Network I/O Control feature offers improved network resource reservation and allocation across the entire switch.

Network I/O Control version 3 for NSX-T Data Center supports the resource management of the system traffic related to virtual machines and to infrastructure services, such as vSphere Fault Tolerance. System traffic is strictly associated with an ESXi host.
Note: NIOC profiles cannot be applied to NSX Edge transport nodes.

Bandwidth Guarantee to System Traffic

Network I/O Control version 3 provisions bandwidth to the network adapters of virtual machines by using constructs of shares, reservation, and limit. These constructs can be defined in the NSX-T Data Center Manager UI. The bandwidth reservation for virtual machine traffic is also used in the admission control. When you power on a virtual machine, admission control utility verifies that enough bandwidth is available before placing a VM on a host that can provide the resource capacity.

Bandwidth Allocation for System Traffic

You can configure Network I/O Control to allocate a certain amount of bandwidth for traffic generated by vSphere Fault Tolerance, vSphere vMotion, virtual machines, and so on.
  • Management Traffic: is traffic for a host management
  • Fault Tolerance (FT) traffic: is traffic for failover and recovery.
  • NFS Traffic: is traffic related to a file transfer in the network file system.
  • vSAN Traffic: is traffic generated by virtual storage area network.
  • vMotion Traffic: is traffic for computing resource migration.
  • vSphere Replication Traffic: is traffic for replication.
  • vSphere Data Protection Backup Traffic: is traffic generated by backup of data.
  • Virtual machine Traffic: is traffic generated by virtual machines.
  • iSCSI Traffic: is traffic for Internet Small Computer System Interface.

vCenter Server propagates the allocation from the distributed switch to each physical adapter on the hosts that are connected to the switch.

Bandwidth Allocation Parameters for System Traffic

By using several configuration parameters, the Network I/O Control service allocates the bandwidth to traffic from basic vSphere system features. Allocation Parameters for System Traffic.

Allocation Parameters for System Traffic

  • Shares: Shares, from 1 to 100, reflect the relative priority of a system traffic type against the other system traffic types that are active on the same physical adapter. The relative shares assigned to a system traffic type and the amount of data transmitted by other system features determine the available bandwidth for that system traffic type.
  • Reservation: The percentage of uplink bandwidth that must be guaranteed on a single physical adapter. The total bandwidth reserved among all system traffic types cannot exceed 75 percent of the bandwidth that the physical network adapter with the lowest capacity can provide. Reserved bandwidth that is unused becomes available to other types of system traffic. However, Network I/O Control does not redistribute the capacity that system traffic does not use to virtual machine placement.
  • Limit: The maximum bandwidth, in Mbps or Gbps, that a system traffic type can consume on a single physical adapter.
Note: You can reserve no more than 75 percent of the bandwidth of a physical network adapter.

For example, if the network adapters connected to an ESXi host are 10 GbE, you can only allocate 7.5 Gbps bandwidth to the various traffic types. You might leave more capacity unreserved. The host can allocate the unreserved bandwidth dynamically according to shares, limits, and use. The host reserves only the bandwidth that is enough for the operation of a system feature.