6.7

Table Of Contents
Defining Bandwidth Requirements for a Virtual Machine
You allocate bandwidth to an individual virtual machine similarly to allocating CPU and memory
resources. Network I/O Control version 3 provisions bandwidth to a virtual machine according to shares,
reservation, and limits that are defined for a network adapter in the VM hardware settings. The
reservation represents a guarantee that the traffic from the virtual machine can consume at least the
specified bandwidth. If a physical adapter has more capacity, the virtual machine may use additional
bandwidth according to the specified shares and limit.
Bandwidth Provisioning to a Virtual Machine on the Host
To guarantee bandwidth, Network I/O Control implements a traffic placement engine that becomes active
if a virtual machine has bandwidth reservation configured. The distributed switch attempts to place the
traffic from a VM network adapter to the physical adapter that can supply the required bandwidth and is in
the scope of the active teaming policy.
The total bandwidth reservation of the virtual machines on a host cannot exceed the reserved bandwidth
that is configured for the virtual machine system traffic.
The actual limit and reservation also depends on the traffic shaping policy for the distributed port group
the adapter is connected to. For example, if a VM network adapter requires a limit of 200 Mbps and the
average bandwidth configured in the traffic shaping policy is 100 Mbps, then the effective limit becomes
100Mbps.
Figure 112. Configuration for Bandwidth Allocation for Individual Virtual Machines
Tenant A
Port Group
vmnic0
10 Gbps
Uplink Port Group
Bandwidth reservation
for VM system traffic:
0.5 Gbps
Tenant A
VM
Tenant B
VM
50 2 Gbps
0.2 Gbps
50
2 Gbps 0.3 Gbps
Tenant B
Port Group
vSphere Distributed
Switch
Total VM reservation:
Less than or equal to
the reservation for
VM system traffic
Shares
Limit Reservation
Traffic
VM
ESXi Host
VM
vSphere Networking
VMware, Inc. 180