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VTNET(4)	       FreeBSD Kernel Interfaces Manual		      VTNET(4)

NAME
     vtnet -- VirtIO Ethernet driver

SYNOPSIS
     To	compile	this driver into the kernel, place the following lines in your
     kernel configuration file:

	   device if_vtnet

     Alternatively, to load the	driver as a module at boot time, place the
     following line in loader.conf(5):

	   if_vtnet_load="YES"

DESCRIPTION
     The vtnet device driver provides support for VirtIO Ethernet devices.

     If	the hypervisor advertises the appreciate features, the vtnet driver
     supports TCP/UDP checksum offload for both	transmit and receive, TCP seg-
     mentation offload (TSO), TCP large	receive	offload	(LRO), and hardware
     VLAN tag stripping/insertion features, as well as a multicast hash	fil-
     ter, as well as Jumbo Frames (up to 9216 bytes), which can	be configured
     via the interface MTU setting.  Selecting an MTU larger than 1500 bytes
     with the ifconfig(8) utility configures the adapter to receive and	trans-
     mit Jumbo Frames.

     For more information on configuring this device, see ifconfig(8).

LOADER TUNABLES
     Tunables can be set at the	loader(8) prompt before	booting	the kernel or
     stored in loader.conf(5).

     hw.vtnet.csum_disable

     hw.vtnet.X.csum_disable
	     This tunable disables receive and send checksum offload.  The
	     default value is 0.

     hw.vtnet.tso_disable

     hw.vtnet.X.tso_disable
	     This tunable disables TSO.	 The default value is 0.

     hw.vtnet.lro_disable

     hw.vtnet.X.lro_disable
	     This tunable disables LRO.	 The default value is 0.

     hw.vtnet.mq_disable

     hw.vtnet.X.mq_disable
	     This tunable disables multiqueue.	The default value is 0.

     hw.vtnet.mq_max_pairs

     hw.vtnet.X.mq_max_pairs
	     This tunable sets the maximum number of transmit and receive
	     queue pairs.  Multiple queues are only supported when the Multi-
	     queue feature is negotiated.  This	driver supports	a maximum of 8
	     queue pairs.  The number of queue pairs used is the lesser	of the
	     maximum supported by the driver and the hypervisor, the number of
	     CPUs present in the guest,	and this tunable if not	zero.  The
	     default value is 0.

SEE ALSO
     arp(4), netintro(4), ng_ether(4), virtio(4), vlan(4), ifconfig(8)

HISTORY
     The vtnet driver was written by Bryan Venteicher <bryanv@FreeBSD.org>.
     It	first appeared in FreeBSD 9.0.

CAVEATS
     The vtnet driver only supports LRO	when the hypervisor advertises the
     mergeable buffer feature.

FreeBSD	10.1		       January 22, 2012			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | LOADER TUNABLES | SEE ALSO | HISTORY | CAVEATS

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<http://www.freebsd.org/cgi/man.cgi?query=vtnet&sektion=4&manpath=FreeBSD+10.0-RELEASE>

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