Using Multicast for Peer Discovery

UDP/IP multicasting is the default for peer-to-peer membership discovery, and it is the easiest to use out of the box when you are trying out a new version of GemFire Enterprise.

You can use multicasting for peer-to-peer discovery even if you use locators for client discovery of servers. To do this, set the multicast properties as indicated below, and start your locators with the ‑peer locator property set to false.

Locators are recommended for discovery in production systems.

To use multicasting for discovery, leave the locators attribute for the distributed system blank, or remove the line from the gemfire.properties file:

        locators=
      

To configure a non-default multicast address or port, set the mcast-port and the mcast-address in the gemfire.properties file of each application and cache server:

        mcast-address=IP_address
      

        mcast-port=port
      

Take care to select both unique multicast ports and unique addresses for your distributed systems. Do not use the same port number for two different systems. Some operating systems may not keep communication separate between systems that have unique addresses but the same port number.

To use multicast for the distribution of region operations, you need to also enable it at the region level. For details, see Peer-to-Peer Messaging and Distribution.

You can use the default port and address if you wish. Setting the port to 0 (zero) disables multicast for the member.