<connections xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://sumo.dlr.de/xsd/connections_file.xsd">
<connection from="1si" to="3o"/>
<connection from="1si" to="2o"/>
<connection from="2si" to="4o"/>
<connection from="2si" to="1o"/>
</connections>