Changing networking configuration options

The QoS value limits the rate of transmission from the VM. The QoS setting does not limit the amount of data the VM can receive. If such a limit is desired, Citrix recommends limiting the rate of incoming packets higher up in the network (for example, at the switch level).

Depending on networking stack configured in the pool, you can set the Quality of Service (QoS) value on VM virtual interfaces (VIFs) in one of two places—either a) on the vSwitch Controller or b) in XenServer (using the CLI or XenCenter)—as described in the following table:

Networking Stack	Configuration Methods Available

vSwitch	•	vSwitch Controller. This is the preferred method
		of setting the maximum transmission rate on a VIF
		when the vSwitch is the networking stack. When
		using the vSwitch stack, the XenCenter QoS option
		is not available.
	•	xe commands. It is possible to set the QoS transmit
		rate using the commands in the example that
		follows. However, the preferred method is through
		the vSwitch Controller UI, which provides more
		finely grained control.

Linux bridge	•	XenCenter. You can set the QoS transmit rate
		limit value in the properties dialog for the virtual
		interface.
	•	xe commands. You can set the QoS transmit rate
		using the CLI using the commands in the section
		that follow.

Important:

When the vSwitch is configured as the networking stack, it is possible to inadvertently configure a QoS value on the vSwitch Controller and inside of the XenServer host. In this case, XenServer limits the outgoing traffic using the lowest rate that you set.

Example of CLI command for QoS:

To limit a VIF to a maximum transmit rate of 100 kilobytes per second using the CLI, use the vif-param-setcommand:

xe vif-param-set uuid=<vif_uuid> qos_algorithm_type=ratelimit xe vif-param-set uuid=<vif_uuid> qos_algorithm_params:kbps=100

Note:

If you are using the vSwitch Controller, Citrix recommends setting the transmission rate limit in the vSwitch Controller instead of this CLI command. For directions on setting the QoS rate limit in the vSwitch Controller, see the vSwitch Controller User Guide.