-{pve} uses a bridged networking model. Each host can have up to 4094
-bridges. Bridges are like physical network switches implemented in
-software. All VMs can share a single bridge, as if
-virtual network cables from each guest were all plugged into the same
-switch. But you can also create multiple bridges to separate network
-domains.
-
-For connecting VMs to the outside world, bridges are attached to
-physical network cards. For further flexibility, you can configure
-VLANs (IEEE 802.1q) and network bonding, also known as "link
-aggregation". That way it is possible to build complex and flexible
-virtual networks.
-
-Debian traditionally uses the `ifup` and `ifdown` commands to
-configure the network. The file `/etc/network/interfaces` contains the
-whole network setup. Please refer to to manual page (`man interfaces`)
-for a complete format description.
-
-NOTE: {pve} does not write changes directly to
-`/etc/network/interfaces`. Instead, we write into a temporary file
-called `/etc/network/interfaces.new`, and commit those changes when
-you reboot the node.
-
-It is worth mentioning that you can directly edit the configuration
-file. All {pve} tools tries hard to keep such direct user
-modifications. Using the GUI is still preferable, because it
-protect you from errors.
-
+{pve} is using the Linux network stack. This provides a lot of flexibility on
+how to set up the network on the {pve} nodes. The configuration can be done
+either via the GUI, or by manually editing the file `/etc/network/interfaces`,
+which contains the whole network configuration. The `interfaces(5)` manual
+page contains the complete format description. All {pve} tools try hard to keep
+direct user modifications, but using the GUI is still preferable, because it
+protects you from errors.
+
+A 'vmbr' interface is needed to connect guests to the underlying physical
+network. They are a Linux bridge which can be thought of as a virtual switch
+to which the guests and physical interfaces are connected to. This section
+provides some examples on how the network can be set up to accomodate different
+use cases like redundancy with a xref:sysadmin_network_bond['bond'],
+xref:sysadmin_network_vlan['vlans'] or
+xref:sysadmin_network_routed['routed'] and
+xref:sysadmin_network_masquerading['NAT'] setups.
+
+The xref:chapter_pvesdn[Software Defined Network] is an option for more complex
+virtual networks in {pve} clusters.
+
+WARNING: It's discourage to use the Debian traditional tools `ifup` and `ifdown`
+if unsure, as they have some pitfalls like interupting all guest traffic on
+`ifdown vmbrX` but not reconnecting those guest again when doing `ifup` on the
+same bridge later.
+
+Apply Network Changes
+~~~~~~~~~~~~~~~~~~~~~
+
+{pve} does not write changes directly to `/etc/network/interfaces`. Instead, we
+write into a temporary file called `/etc/network/interfaces.new`, this way you
+can do many related changes at once. This also allows to ensure your changes
+are correct before applying, as a wrong network configuration may render a node
+inaccessible.
+
+Live-Reload Network with ifupdown2
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+With the recommended 'ifupdown2' package (default for new installations since
+{pve} 7.0), it is possible to apply network configuration changes without a
+reboot. If you change the network configuration via the GUI, you can click the
+'Apply Configuration' button. This will move changes from the staging
+`interfaces.new` file to `/etc/network/interfaces` and apply them live.
+
+If you made manual changes directly to the `/etc/network/interfaces` file, you
+can apply them by running `ifreload -a`
+
+NOTE: If you installed {pve} on top of Debian, or upgraded to {pve} 7.0 from an
+older {pve} installation, make sure 'ifupdown2' is installed: `apt install
+ifupdown2`
+
+Reboot Node to Apply
+^^^^^^^^^^^^^^^^^^^^
+
+Another way to apply a new network configuration is to reboot the node.
+In that case the systemd service `pvenetcommit` will activate the staging
+`interfaces.new` file before the `networking` service will apply that
+configuration.