Network resource pools determine the bandwidth that different network traffic types are given on a vSphere distributed switch.
When network I/O control is enabled, distributed switch traffic is divided into the following predefined network resource pools: Fault Tolerance traffic, iSCSI traffic, vMotion traffic, management traffic, vSphere Replication (VR) traffic, NFS traffic, and virtual machine traffic.
You can also create custom network resource pools for virtual machine traffic. You can control the bandwidth each network resource pool is given by setting the physical adapter shares and host limit for each network resource pool.
The host limit of a network resource pool is the upper limit of bandwidth that the network resource pool can use.
Assigning a QoS priority tag to a network resource pool applies an 802.1p tag to all outgoing packets associated with that network resource pool.