PING - uses IP multicast over existing UDP transport

MPING - uses IP multicast over separate UDP transport

BPING - uses IP broadcast

TCPPING - uses list of member addresses

TCPGOSSIP - uses specialized router

FILE_PING - uses shared directory to keep track of members

JDBC_PING - uses shared database to keep track of members

RACKSPACE_PING - uses Rackspace Cloud File Storage

S3_PING - uses Amazon Simple Storage Service