The PING discovery protocol normally sits on top of the UDP transport protocol. Each node responds with a unicast UDP datagram back to the sender. Here is an example PING configuration under the JGroups Config element.
<PING timeout="2000"
num_initial_members="2"/>
The available attributes in the PING element are listed below.
timeout specifies the maximum number of milliseconds to wait for any responses.
num_initial_members specifies the maximum number of responses to wait for.
gossip_host specifies the host on which the GossipRouter is running.
gossip_port specifies the port on which the GossipRouter is listening on.
gossip_refresh specifies the interval (in milliseconds) for the lease from the GossipRouter.
initial_hosts is a comma-seperated list of addresses (e.g., host1[12345],host2[23456]), which are pinged for discovery.
If both gossip_host and gossip_port are defined, the cluster uses the GossipRouter for the initial discovery. If the initial_hosts is specified, the cluster pings that static list of addresses for discovery. Otherwise, the cluster uses IP multicasting for discovery.
The discovery phase returns when the timeout ms have elapsed or the num_initial_members responses have been received.