In clustered mode, Infinispan uses JGroups to enable intermachine communication between nodes within a cluster. It is also used for discovery of new members, departing members, state transfer, failure detection, and reliable delivery.

JGroups provides a declarative way to manage the protocols by using a configuration XML file that will be used to determine the behavior and characteristics of each protocol in JGroups.

To start using Infinispan, you're not required to create or provide a configuration file because, by default, Infinispan uses a configuration file called jgroups-udp.xml bundled in the infinispan-core.jar file. Additionally, you have two other built-in configuration files that you can use within infinispan-core.jar, which are as follows: