<?xml version="1.0"?>
<element xmlns="http://relaxng.org/ns/structure/1.0" name="device">
<choice>
<group>
<attribute name="link">
<value>ethernet</value>
</attribute>
<optional>
<element name="ethernet-element">
<text/>
</element>
</optional>
</group>
<group>
<attribute name="link">
<value>serial</value>
</attribute>
<optional>
<element name="serial-element">
<text/>
</element>
</optional>
</group>
</choice>
</element>