<div class="wiki-content maincontent"><p>Discovery refers to either a client (producer or consumer) establishing a 'transport connector' to the broker or a broker establishing 'network connector' to another broker without explicit static configuration of broker (IP or hostname).</p>

<p>The scheme 'multicast' refers to either listening for or advertising discovery events on a multicast address. zeroconf is similar to multicast, except for protocol specific to Apple's Rendezvous (bonjour).</p>

<h3>Broker</h3>

<structured-macro ac:macro-id="22ee5d65-5851-470c-a809-e0b90e776c32" ac:name="code" ac:schema-version="1"><plain-text-body>
   &lt;networkConnectors&gt;
     &lt;networkConnector name="default" uri="multicast://default"/&gt;
   &lt;/networkConnectors&gt;
</plain-text-body></structured-macro>

<p>The above configuration in the broker xml file will make it automatically establish network connectors to other brokers that advertise themselves on the multicast address: when this broker gets a discovery event from another broker, the event has information that enables it to establish network connector to that broker.</p>

<p>Self-advertisement is facilitated by the following config:</p>


<structured-macro ac:macro-id="c21df2d5-ec0c-46d7-958e-1e248b26908d" ac:name="code" ac:schema-version="1"><plain-text-body> 
  &lt;transportConnectors&gt;
      &lt;transportConnector name="default" uri="tcp://localhost:61616" discoveryUri="multicast://default"/&gt;
   &lt;/transportConnectors&gt;
</plain-text-body></structured-macro>

<h3>Client</h3>

<p>An example usage of discovery on the client side (using the transport 'discovery' that uses discovery agent) ...</p>


<structured-macro ac:macro-id="bd132e4e-2190-4c96-b5cc-b400f1ee251f" ac:name="code" ac:schema-version="1"><plain-text-body>
 &lt;transportConnectors&gt;
      &lt;transportConnector name="default" uri="discovery:(multicast://default)"/&gt;
   &lt;/transportConnectors&gt;
</plain-text-body></structured-macro>

<p>ps: discovery (which is a confusing name) is just like a 'reliable' transport such as <link><page ri:content-title="Failover Transport Reference"></page><link-body>failover</link-body></link>. If it is unable to connect to a broker, it will try another broker (assuming it<br clear="none">
heard its advertisement over multicast).</p></div>