To set up a Tcp socket server in Mule for request/response processing you just need to add an inbound tcp endpoint to your component.

To set up a simple echo tcp server use the following configuration.

<mule-configuration id="Echo_Tcp_Server" version="1.0">
    <model name="dev">
        <mule-descriptor name="echoComponent"
            implementation="org.mule.components.simple.EchoComponent">
            <inbound-router>
                <endpoint address="tcp://localhost:12345" synchronous="true"/>
            </inbound-router>
        </mule-descriptor>
    </model>
</mule-configuration>

This will set up a tcp service to accept requests on localhost:12345. Note that the endpoint is synchronous which means that the request will be processed in a single thread and any return data will be sent back to the tcp client (in this case the echo component just returns the data it receives).