The layers.xml explains how an entire map or part of a map can be described by service and layer level.
XML-syntax is changing depending on the type of service you use. Different services can be combined together.

Example of a ArcIMS-xml

This example shows a map existing of two layers.

<filter queryid="Landcover">

<connector    transparent="-1"
                   serveroutputformat="png"
                   type="IMSConnector"
                   serverName="geonode.eea.europa.eu"
                   serviceName="wise">

<!-- CLC raster-->
<layer
            name="Corine Land Cover 1990 raster (1:25M)"
            featuretype="image"
            viewlegend="false"
            layerid="clc90raster"
            minscale="1:1500000"
            visible="false"
            fromlayer="sdeims_landcover.GISEDITOR.CLC90_100M_V5_BG.RASTER"
            featureclasstype="image"
            workspace="sdeims_landcover">
</layer>

<layer
            name="Corine Land Cover 2000 raster (1:25M)"
            featuretype="image"
            viewlegend="false"
            layerid="clc00raster"
            minscale="1:1500000"
            visible="true"
            fromlayer="sdeims_landcover.GISEDITOR.CLC00_100M_V5_BG.RASTER"
            featureclasstype="image"
            workspace="sdeims_landcover">
</layer>

    </connector>

</filter>