1  <?xml version="1.0"?>
 2  <element xmlns="http://relaxng.org/ns/structure/1.0" name="device">
 3      <choice>
 4        <group>
 5  	<attribute name="link">
 6  	  <value>ethernet</value>
 7  	</attribute>
 8  	<optional>
 9  	  <element name="ethernet-element">
10  	    <text/>
11  	  </element>
12  	</optional>
13        </group>
14        <group>
15  	<attribute name="link">
16  	  <value>serial</value>
17  	</attribute>
18  	<optional>
19  	  <element name="serial-element">
20  	    <text/>
21  	  </element>
22  	</optional>
23        </group>
24      </choice>
25  </element>