diff --git a/docs/schemas/interface.rng b/docs/schemas/interface.rng
new file mode 100644
index 0000000..bed2f0a
--- /dev/null
+++ b/docs/schemas/interface.rng
@@ -0,0 +1,385 @@
+<!-- A Relax NG schema for network interfaces -->
+<grammar xmlns="http://relaxng.org/ns/structure/1.0"
+         datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
+  <start>
+    <choice>
+      <ref name="ethernet-interface"/>
+      <ref name="bridge-interface"/>
+      <ref name="bond-interface"/>
+      <ref name="vlan-interface"/>
+    </choice>
+  </start>
+
+  <!--
+       FIXME: How do we handle VLAN's ? Should they be their own interface
+       or should we treat them as an option on the base interface ?  For
+       example, for vlan eth0.42, it would make sense to make that part of
+       the definition of the eth0 interface.
+  -->
+
+  <!--
+       Ethernet adapter
+  -->
+  <define name="basic-ethernet-content">
+    <attribute name="type">
+      <value>ethernet</value>
+    </attribute>
+    <ref name="name-attr"/>
+    <!-- If no MAC is given when the interface is defined, it is determined
+         by using the device name.
+         FIXME: What if device name and MAC don't specify the same NIC ? -->
+    <optional>
+      <element name="mac">
+        <attribute name="address"><ref name="mac-addr"/></attribute>
+      </element>
+    </optional>
+    <!-- FIXME: Allow (some) ethtool options -->
+  </define>
+
+  <!-- Ethernet adapter without IP addressing, e.g. for a bridge -->
+  <define name="bare-ethernet-interface">
+    <element name="interface">
+      <ref name="basic-ethernet-content"/>
+    </element>
+  </define>
+
+  <define name="ethernet-interface">
+    <element name="interface">
+      <ref name="startmode"/>
+      <ref name="basic-ethernet-content"/>
+      <ref name="mtu"/>
+      <ref name="interface-addressing"/>
+    </element>
+  </define>
+
+  <!--
+      VLAN's
+  -->
+  <define name="vlan-interface-common">
+    <attribute name="type">
+      <value>vlan</value>
+    </attribute>
+    <!-- The name attribute is only useful for reporting back and is always
+         of the form DEVICE.VLAN
+    -->
+    <optional><ref name="name-attr"/></optional>
+  </define>
+
+  <define name="vlan-device">
+    <element name="vlan">
+      <attribute name="tag"><ref name="vlan-id"/></attribute>
+      <element name="interface">
+        <attribute name="name"><ref name="device-name"/></attribute>
+      </element>
+    </element>
+  </define>
+
+  <define name="bare-vlan-interface">
+    <element name="interface">
+      <ref name="vlan-interface-common"/>
+      <ref name="vlan-device"/>
+    </element>
+  </define>
+
+  <define name="vlan-interface">
+    <element name="interface">
+      <ref name="vlan-interface-common"/>
+      <ref name="startmode"/>
+      <ref name="mtu"/>
+      <ref name="interface-addressing"/>
+      <ref name="vlan-device"/>
+    </element>
+  </define>
+
+  <!--
+       Bridges
+  -->
+  <define name="bridge-interface">
+    <element name="interface">
+      <attribute name="type">
+        <value>bridge</value>
+      </attribute>
+      <ref name="name-attr"/>
+      <ref name="startmode"/>
+      <ref name="mtu"/>
+      <ref name="interface-addressing"/>
+      <element name="bridge">
+        <optional>
+          <attribute name="stp">
+            <ref name="on-or-off"/>
+          </attribute>
+        </optional>
+        <oneOrMore>
+          <choice>
+            <ref name="bare-ethernet-interface"/>
+            <ref name="bare-vlan-interface"/>
+          </choice>
+        </oneOrMore>
+      </element>
+    </element>
+  </define>
+  <!-- Jim Fehlig would like support for other bridge attributes, in
+       particular hellotime, forwarddelay, and maxage
+  -->
+
+  <!--
+      Bonds
+  -->
+  <define name="bond-interface">
+    <element name="interface">
+      <attribute name="type">
+        <value>bond</value>
+      </attribute>
+      <ref name="name-attr"/>
+      <ref name="startmode"/>
+      <ref name="mtu"/>
+      <ref name="interface-addressing"/>
+      <element name="bond">
+        <optional>
+          <attribute name="mode">
+            <choice>
+              <value>balance-rr</value>
+              <!-- The primary interface is the first interface child
+                   of the bond element -->
+              <value>active-backup</value>
+              <value>balance-xor</value>
+              <value>broadcast</value>
+              <value>802.3ad</value>
+              <value>balance-tlb</value>
+              <value>balance-alb</value>
+            </choice>
+          </attribute>
+        </optional>
+
+        <!-- FIXME: add more attributes
+
+             mode == 802.3ad
+               ad_select
+               lacp_rate
+               xmit_hash_policy
+
+             mode == active-backup
+               fail_over_mac
+               num_grat_arp when mode == active-backup (since 3.3.0)
+               num_unsol_na when mode == active-backup (ipv6, since 3.4.0)
+
+             mode == balance-xor
+               xmit_hash_policy       (since 2.6.3/3.2.2)
+        -->
+
+        <choice>
+          <element name="miimon">
+            <!-- miimon frequency in ms -->
+            <attribute name="freq"><ref name="uint"/></attribute>
+            <optional>
+              <attribute name="downdelay"><ref name="uint"/></attribute>
+            </optional>
+            <optional>
+              <attribute name="updelay"><ref name="uint"/></attribute>
+            </optional>
+            <optional>
+              <!-- use_carrier -->
+              <attribute name="carrier">
+                <choice>
+                  <!-- use MII/ETHTOOL ioctl -->
+                  <value>ioctl</value>
+                  <!-- use netif_carrier_ok() -->
+                  <value>netif</value>
+                </choice>
+              </attribute>
+            </optional>
+          </element>
+          <element name="arpmon">
+            <attribute name="interval"><ref name="uint"/></attribute>
+            <attribute name="target"><ref name="ipv4-addr"/></attribute>
+            <optional>
+              <attribute name="validate">
+                <choice>
+                  <value>none</value>
+                  <value>active</value>
+                  <value>backup</value>
+                  <value>all</value>
+                </choice>
+              </attribute>
+            </optional>
+          </element>
+        </choice>
+        <oneOrMore>
+          <!-- The slave interfaces -->
+          <ref name="bare-ethernet-interface"/>
+        </oneOrMore>
+      </element>
+    </element>
+  </define>
+
+  <!-- Basic attributes for all interface types -->
+  <define name="name-attr">
+    <!-- The device name, like eth0 or br2 -->
+    <attribute name="name"><ref name="device-name"/></attribute>
+  </define>
+
+  <define name="mtu">
+    <optional>
+      <element name="mtu">
+        <attribute name="size"><ref name="uint"/></attribute>
+      </element>
+    </optional>
+  </define>
+
+  <define name="startmode">
+    <element name="start">
+      <attribute name="mode">
+        <choice>
+          <value>onboot</value>
+          <value>none</value>
+          <value>hotplug</value>
+          <!-- Jim Fehlig lists the following that SuSe supports:
+               manual, ifplug, nfsroot -->
+        </choice>
+      </attribute>
+    </element>
+  </define>
+
+  <!--
+       Assignment of addresses to an interface, allowing for
+       different protocols
+  -->
+  <define name="interface-addressing">
+    <optional>
+      <element name="protocol">
+        <ref name="protocol-ipv4"/>
+      </element>
+    </optional>
+  </define>
+
+  <define name="protocol-ipv4">
+    <attribute name="family">
+      <value>ipv4</value>
+    </attribute>
+    <choice>
+      <element name="dhcp">
+        <optional>
+          <attribute name="peerdns">
+            <ref name="yes-or-no"/>
+          </attribute>
+        </optional>
+      </element>
+      <!-- FIXME: This format should be good enough for IPv4 and IPv6, i.e.
+
+           ipaddr="192.168.0.5/24"
+           ipaddr="2001:DB8:ABCD::1/64"
+
+           but will cause some backend pain
+      -->
+      <group>
+        <element name="ip">
+          <attribute name="address"><ref name="ipv4-addr"/></attribute>
+          <optional>
+            <attribute name="prefix"><ref name="ipv4-prefix"/></attribute>
+          </optional>
+        </element>
+        <optional>
+          <element name="route">
+            <attribute name="gateway"><ref name="ipv4-addr"/></attribute>
+          </element>
+        </optional>
+      </group>
+    </choice>
+  </define>
+  <!-- Jim Fehlig (<jfehlig@novell.com>) suggest the
+       following additions to DHCP:
+
+       WRT dhcp element, would it make sense to consider hostname (hostname
+       to send to server) and if to change the local hostname to the
+       hostname delivered via dhcp?  E.g.  hostname="foo" (default
+       `hostname`) sethostname
+
+       Also route:
+         setrouting (default "yes")
+         setdefaultroute (default "yes")
+
+       and NIS:
+         nis (default "yes")
+         setnisdomain (default "yes")
+
+       What about dhcpv6?  A separate <dhcp6 /> element?
+  -->
+
+  <!-- Jim Fehlig suggest adding static routing info
+
+       As for routing info, how about a separate route element:
+
+       <route gateway="192.168.0.1" /> # destination=default
+       <route destination="default" gateway="192.168.0.1" />
+       <route destination="10.0.0.0/8" gateway="192.168.0.2" />
+       <route destination="2001:DB8:C::/64" gateway="2001:DB8:C::1" />
+       <route destination="2001:DB8::/32"> # unrecheable route (loopback)
+
+       It would perhaps make sense to use iproute2 names, that is prefix
+       instead of destination and nexthop instead of gateway.
+  -->
+
+  <!-- Auxiliary definitions -->
+  <define name="on-or-off">
+    <choice>
+      <value>on</value>
+      <value>off</value>
+    </choice>
+  </define>
+
+  <define name="yes-or-no">
+    <choice>
+      <value>yes</value>
+      <value>no</value>
+    </choice>
+  </define>
+
+  <!-- Type library -->
+
+  <define name='uint'>
+    <data type='unsignedInt'>
+      <param name="pattern">[0-9]+</param>
+    </data>
+  </define>
+
+  <define name='device-name'>
+    <data type='string'>
+      <param name="pattern">[a-zA-Z0-9_\.\-:/]+</param>
+    </data>
+  </define>
+
+  <define name='UUID'>
+    <choice>
+      <data type='string'>
+        <param name="pattern">[a-fA-F0-9]{32}</param>
+      </data>
+      <data type='string'>
+        <param name="pattern">[a-fA-F0-9]{8}\-([a-fA-F0-9]{4}\-){3}[a-fA-F0-9]{12}</param>
+      </data>
+    </choice>
+  </define>
+
+  <define name='mac-addr'>
+    <data type='string'>
+      <param name="pattern">([a-fA-F0-9]{2}:){5}[a-fA-F0-9]{2}</param>
+    </data>
+  </define>
+
+  <define name='ipv4-addr'>
+    <data type='string'>
+      <param name="pattern">([0-2]?[0-9]?[0-9]\.){3}[0-2]?[0-9]?[0-9]</param>
+    </data>
+  </define>
+
+  <define name='ipv4-prefix'>
+    <data type='string'>
+      <param name="pattern">[1-9]|[12][0-9]|3[0-2]</param>
+    </data>
+  </define>
+
+  <define name='vlan-id'>
+    <data type="unsignedInt">
+      <param name="maxInclusive">4096</param>
+    </data>
+  </define>
+</grammar>
diff --git a/tests/interfaceschemadata/bond-arp.xml b/tests/interfaceschemadata/bond-arp.xml
new file mode 100644
index 0000000..7b4ed6f
--- /dev/null
+++ b/tests/interfaceschemadata/bond-arp.xml
@@ -0,0 +1,12 @@
+<interface type='bond' name='bond0'>
+  <start mode='none'/>
+  <protocol family='ipv4'>
+    <ip address='192.168.50.7' prefix='24'/>
+    <route gateway='192.168.50.1'/>
+  </protocol>
+  <bond mode='active-backup'>
+    <arpmon interval='100' target='192.168.50.1' validate='active'/>
+    <interface type='ethernet' name='eth1'/>
+    <interface type='ethernet' name='eth0'/>
+  </bond>
+</interface>
diff --git a/tests/interfaceschemadata/bond.xml b/tests/interfaceschemadata/bond.xml
new file mode 100644
index 0000000..81b92e3
--- /dev/null
+++ b/tests/interfaceschemadata/bond.xml
@@ -0,0 +1,12 @@
+<interface type='bond' name='bond0'>
+  <start mode='none'/>
+  <protocol family='ipv4'>
+    <ip address='192.168.50.7' prefix='24'/>
+    <route gateway='192.168.50.1'/>
+  </protocol>
+  <bond mode='active-backup'>
+    <miimon freq='100' updelay='10' carrier='ioctl'/>
+    <interface type='ethernet' name='eth1'/>
+    <interface type='ethernet' name='eth0'/>
+  </bond>
+</interface>
diff --git a/tests/interfaceschemadata/bridge-no-address.xml b/tests/interfaceschemadata/bridge-no-address.xml
new file mode 100644
index 0000000..cddafb1
--- /dev/null
+++ b/tests/interfaceschemadata/bridge-no-address.xml
@@ -0,0 +1,10 @@
+<interface type='bridge' name='br0'>
+  <start mode='onboot'/>
+  <mtu size='1500'/>
+  <bridge stp='off'>
+    <interface type='ethernet' name='eth0'>
+      <mac address='ab:bb:cc:dd:ee:ff'/>
+    </interface>
+    <interface type='ethernet' name='eth1'/>
+  </bridge>
+</interface>
diff --git a/tests/interfaceschemadata/bridge-vlan.xml b/tests/interfaceschemadata/bridge-vlan.xml
new file mode 100644
index 0000000..77f992d
--- /dev/null
+++ b/tests/interfaceschemadata/bridge-vlan.xml
@@ -0,0 +1,13 @@
+<interface type='bridge' name='br0'>
+  <start mode='onboot'/>
+  <protocol family='ipv4'>
+    <dhcp/>
+  </protocol>
+  <bridge stp='off'>
+    <interface type='vlan' name='eth0.42'>
+      <vlan tag='42'>
+        <interface  name='eth0'/>
+      </vlan>
+    </interface>
+  </bridge>
+</interface>
diff --git a/tests/interfaceschemadata/bridge.xml b/tests/interfaceschemadata/bridge.xml
new file mode 100644
index 0000000..1f17114
--- /dev/null
+++ b/tests/interfaceschemadata/bridge.xml
@@ -0,0 +1,13 @@
+<interface type='bridge' name='br0'>
+  <start mode='onboot'/>
+  <mtu size='1500'/>
+  <protocol family='ipv4'>
+    <dhcp/>
+  </protocol>
+  <bridge stp='off'>
+    <interface type='ethernet' name='eth0'>
+      <mac address='ab:bb:cc:dd:ee:ff'/>
+    </interface>
+    <interface type='ethernet' name='eth1'/>
+  </bridge>
+</interface>
diff --git a/tests/interfaceschemadata/bridge42.xml b/tests/interfaceschemadata/bridge42.xml
new file mode 100644
index 0000000..c6639ab
--- /dev/null
+++ b/tests/interfaceschemadata/bridge42.xml
@@ -0,0 +1,7 @@
+<interface type='bridge' name='br42'>
+  <start mode='onboot'/>
+  <mtu size='1500'/>
+  <bridge stp='off'>
+    <interface type='ethernet' name='eth42'/>
+  </bridge>
+</interface>
diff --git a/tests/interfaceschemadata/ethernet-dhcp.xml b/tests/interfaceschemadata/ethernet-dhcp.xml
new file mode 100644
index 0000000..fe969df
--- /dev/null
+++ b/tests/interfaceschemadata/ethernet-dhcp.xml
@@ -0,0 +1,8 @@
+<interface type='ethernet' name='eth0'>
+  <start mode='none'/>
+  <mac address='aa:bb:cc:dd:ee:ff'/>
+  <mtu size='1492'/>
+  <protocol family='ipv4'>
+    <dhcp peerdns='no'/>
+  </protocol>
+</interface>
diff --git a/tests/interfaceschemadata/ethernet-static-no-prefix.xml b/tests/interfaceschemadata/ethernet-static-no-prefix.xml
new file mode 100644
index 0000000..891f9fe
--- /dev/null
+++ b/tests/interfaceschemadata/ethernet-static-no-prefix.xml
@@ -0,0 +1,7 @@
+<interface type='ethernet' name='eth1'>
+  <start mode='onboot'/>
+  <protocol family='ipv4'>
+    <ip address='192.168.0.5'/>
+    <route gateway='192.168.0.1'/>
+  </protocol>
+</interface>
diff --git a/tests/interfaceschemadata/ethernet-static.xml b/tests/interfaceschemadata/ethernet-static.xml
new file mode 100644
index 0000000..2c50e44
--- /dev/null
+++ b/tests/interfaceschemadata/ethernet-static.xml
@@ -0,0 +1,7 @@
+<interface type='ethernet' name='eth1'>
+  <start mode='onboot'/>
+  <protocol family='ipv4'>
+    <ip address='192.168.0.5' prefix='24'/>
+    <route gateway='192.168.0.1'/>
+  </protocol>
+</interface>
diff --git a/tests/interfaceschemadata/vlan.xml b/tests/interfaceschemadata/vlan.xml
new file mode 100644
index 0000000..a9570e3
--- /dev/null
+++ b/tests/interfaceschemadata/vlan.xml
@@ -0,0 +1,9 @@
+<interface type='vlan' name='eth0.42'>
+  <start mode='onboot'/>
+  <protocol family='ipv4'>
+    <dhcp peerdns='no'/>
+  </protocol>
+  <vlan tag='42'>
+    <interface name='eth0'/>
+  </vlan>
+</interface>