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<document>
  <properties>
    <title>Lateral UDP Discovery</title>
    <author email="asmuts@apache.org">Aaron Smuts</author>
  </properties>

  <body>
    <section name="Lateral UDP Discovery">
      <p> 
		Rather than list all the other lateral servers in the configuration
		file, you can configure the TCP lateral to use UDP 
		discovery.  In discovery mode, lateral TCP caches will broadcast 
		to a multicast address and port, letting all listeners know where they are.  
  	  </p>
	  <p>	
		On startup each lateral will issue a special message requesting a 
		broadcast from the others caches.  Normal broadcasts occur every 
		30 seconds. (This is to be made configurable.)  Regions that don't 
		receive, are running in send only mode, don't broadcast anything but requests.
  	  </p>
      <p>
	    When a lateral receives a discovery message it will try to add
	    the lateral to the nowait facade for the region.  If it already exists 
	    nothing happens.  If a region is not configured to send laterally, nothing 	
		happens,  since it doesn't have a no wait.
  	  </p>
  	  <p>	
  		This allows you to have the same configuration on every machine.		
      </p>
      <subsection name="Configuration">
        <p>
          The configuration is fairly straightforward and is done in the
          auxiliary cache section of the <code>cache.ccf</code>
          configuration file.  In the example below, I created a TCP
          Lateral Auxiliary Cache referenced by <code>LTCP</code>.  It uses 
          UDP Discovery to locate other servers.  It broadcasts to
          multicast address <code>228.5.6.8</code> and port <code>6780</code>.
          It listens to port <code>1110</code>.
        </p>
        <source><![CDATA[
jcs.auxiliary.LTCP=org.apache.jcs.auxiliary.lateral.socket.tcp.LateralTCPCacheFactory
jcs.auxiliary.LTCP.attributes=org.apache.jcs.auxiliary.lateral.socket.tcp.TCPLateralCacheAttributes
jcs.auxiliary.LTCP.attributes.TcpListenerPort=1110
jcs.auxiliary.LTCP.attributes.PutOnlyMode=true
jcs.auxiliary.LTCP.attributes.UdpDiscoveryAddr=228.5.6.8
jcs.auxiliary.LTCP.attributes.UdpDiscoveryPort=6780
jcs.auxiliary.LTCP.attributes.UdpDiscoveryEnabled=true
        ]]></source>
      </subsection>
    </section>
  </body>
</document>