Network XML format

This page provides an introduction to the network port XML format. This stores information about the connection between a virtual interface of a virtual domain, and the virtual network it is attached to.

Element and attribute overview

The root element required for all virtual network ports is named networkport and has no configurable attributes The network port XML format is available since 5.5.0

General metadata

The first elements provide basic metadata about the virtual network port.

<networkport
  <uuid>7ae63b5f-fe96-4af0-a7c3-da04ba1b3f54</uuid>
  <owner>
    <uuid>06578fc1-c686-46fa-bc2c-220893b466a6</uuid>
    <name>myguest<name>
  </owner>
  <group>webfront<group>
  <mac address='52:54:0:7b:35:93'/>
  ...

uuid

The content of the uuid element provides a globally unique identifier for the virtual network port. The format must be RFC 4122 compliant, eg 3e3fce45-4f53-4fa7-bb32-11f34168b82b. If omitted when defining/creating a new network port, a random UUID is generated.

The owner node records the domain object that is the owner of the network port. It contains two child nodes:

uuid: The content of the uuid element provides a globally unique identifier for the virtual domain.
name: The unique name of the virtual domain

group

The port group in the virtual network to which the port belongs. Can be omitted if no port groups are defined on the network.

mac

The address attribute provides the MAC address of the virtual port that will be see by the guest. The MAC address must not start with 0xFE as this byte is reserved for use on the host side of the port.

Common elements

The following elements are common to one or more of the plug types listed later

  ...
  <bandwidth>
    <inbound average='1000' peak='5000' floor='200' burst='1024'/>
    <outbound average='128' peak='256' burst='256'/>
  </bandwidth>
  <rxfilters trustGuest='yes'/>
  <port isolated='yes'/>
  <virtualport type='802.1Qbg'>
    <parameters managerid='11' typeid='1193047' typeidversion='2'/>
  </virtualport>
  ...

bandwidth: This part of the network port XML provides setting quality of service. Incoming and outgoing traffic can be shaped independently. The bandwidth element and its child elements are described in the QoS section of the Network XML. In addition the classID attribute may exist to provide the ID of the traffic shaping class that is active.
rxfilters: The rxfilters element property trustGuest provides the capability for the host to detect and trust reports from the guest regarding changes to the interface mac address and receive filters by setting the attribute to yes. The default setting for the attribute is no for security reasons and support depends on the guest network device model as well as the type of connection on the host - currently it is only supported for the virtio device model and for macvtap connections on the host.
port: Since 6.1.0. The port element property isolated, when set to yes (default setting is no) is used to isolate this port's network traffic from other ports on the same network that also have <port isolated='yes'/>. This setting is only supported for emulated network devices connected to a Linux host bridge via a standard tap device.
virtualport: The virtualport element describes metadata that needs to be provided to the underlying network subsystem. It is described in the domain XML interface documentation.

Plugs

The plug element has varying content depending on the value of the type attribute.

Network

The network plug type refers to a managed virtual network plug that is based on a traditional software bridge device privately managed by libvirt.

  ...
  <plug type='network' bridge='virbr0'/>
  ...

The bridge attribute provides the name of the privately managed bridge device associated with the virtual network.

Bridge

The bridge plug type refers to an externally managed traditional software bridge.

  ...
  <plug type='bridge' bridge='br2'/>
  ...

The bridge attribute provides the name of the externally managed bridge device associated with the virtual network.

Direct

The direct plug type refers to a connection directly to a physical network interface.

  ...
  <plug type='direct' dev='ens3' mode='vepa'/>
  ...

The dev attribute provides the name of the physical network interface to which the port will be connected. The mode attribute describes how the connection will be setup and takes the same values described in the domain XML.

Host PCI

The hostdev-pci plug type refers to the passthrough of a physical PCI device rather than emulation.

  ...
  <plug type='hostdev-pci' managed='yes'>
    <driver name='vfio'/>
    <address domain='0x0001' bus='0x02' slot='0x03' function='0x4'/>
  </plug>
  ...

The managed attribute indicates who is responsible for managing the PCI device in the host. When set to the value yes libvirt is responsible for automatically detaching the device from host drivers and resetting it if needed. If the value is no, some other party must ensure the device is not attached to any host drivers.