6.5.1

Table Of Contents
Admission Control for Virtual Machine Bandwidth
To guarantee that sufficient bandwidth is available to a virtual machine, vSphere implements admission
control at host and cluster levels based on bandwidth reservation and teaming policy.
Bandwidth Admission Control in vSphere Distributed Switch
When you power on a virtual machine, the Network I/O Control feature on a distributed switch verifies that
these conditions are satisfied on the host.
n
A physical adapter on the host can supply the minimum bandwidth to the VM network adapters in
accordance with the teaming policy and reservation.
n
The reservation for a VM network adapter is less than the free quota in the network resource pool.
If you change the reservation for a network adapter of a running virtual machine, Network I/O Control
verifies again whether the associated network resource pool can accommodate the new reservation. If
the pool does not have enough unclaimed quota, the change is not applied.
To use admission control in vSphere Distributed Switch, perform the following tasks:
n
Configure bandwidth allocation for the virtual machine system traffic on the distributed switch.
n
Configure a network resource pool with a reservation quota from the bandwidth configured for virtual
machine system traffic.
n
Associate the network resource pool with the distributed port group that connects the virtual machines
to the switch.
n
Configure the bandwidth requirements of a virtual machine connected to the port group.
Bandwidth Admission Control in vSphere DRS
If you power on a virtual machine that is in a cluster, vSphere DRS places the virtual machine on a host
that has the capacity to guarantee the bandwidth reserved for the virtual machine according to the active
teaming policy.
vSphere DRS migrates a virtual machine to another host to satisfy the bandwidth reservation of the virtual
machine in these situations:
n
The reservation is changed to a value that the initial host can no longer satisfy.
n
A physical adapter that carries traffic from the virtual machine is offline.
To use admission control in vSphere DRS, perform the following tasks:
n
Configure bandwidth allocation for the virtual machine system traffic on the distributed switch.
n
Configure the bandwidth requirements of a virtual machine that is connected to the distributed switch.
For more information about resource management according to bandwidth demands of virtual machines,
see the vSphere Resource Management documentation.
vSphere Networking
VMware, Inc. 191