VMware vSphere Network I/O Control (NIOC)

VMware vSphere Network I/O Control (NIOC) is a feature that allows an administrator to prioritize bandwidth for different network resource pools on a vNetwork Distributed Switch (vDS).

When enabled, Network NIOC categorizes traffic into network resource pools, which use resource allocation policies to control bandwidth for various traffic types. By default, a shares value of 50 is given to each pool, except for VM traffic, which gets a default of 100. The administrator can adjust the shares value to each pool to determine how much bandwidth a pool gets to fulfill specific service levels. Pools with a higher shares number receive more physical network resources. 

NIOC resource pools include:

• fault tolerance traffic
•  iSCSI traffic
• vMotion traffic
• management traffic
• vSphere Replication traffic
• network file system (NFS) traffic 
• virtual machine (VM) traffic
• host-based replication (HBR) traffic
• User-defined traffic

Network NIOC was first introduced with vSphere 4.1.