Techne

# /etc/systemd/network/br0.netdev

[NetDev]
Name=br0
Kind=bridge

# /etc/systemd/network/br0.network

[Match]
Name=br0

[Network]
Address=10.0.0.96/24
Gateway=10.0.0.1
Broadcast=10.0.0.255

# /etc/systemd/network/eth0.network

[Match]
Name=eth0

[Network]
Bridge=br0

Restart systemd-networkd and verify.

sudo networkctl status br0
sudo brctl show br0 # requires bridge-utils package

<!-- bridge.xml -->

<network>
  <name>br0</name>
  <forward mode="bridge"/>
  <bridge name="br0"/>
</network>

Define, start, and verify the network.

sudo virsh net-define bridge.xml
sudo virsh net-start br0
sudo virsh net-autostart br0
sudo virsh net-list --all