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22.4.4. MPING

MPING uses IP multicast to discover the initial membership. It can be used with all transports, but usually this is used in combination with TCP. TCP usually requires TCPPING, which has to list all group members explicitly, but MPING doesn't have this requirement. The typical use case for this is when we want TCP as transport, but multicasting for discovery so we don't have to define a static list of initial hosts in TCPPING or require external Gossip Router. 

<MPING timeout="2000"
    bind_to_all_interfaces="true"
    mcast_addr="228.8.8.8"
    mcast_port="7500"
    ip_ttl="8"
    num_initial_members="3"
    down_thread="false" up_thread="false"/>

The available attributes in the MPING element are listed below.

  • timeout specifies the maximum number of milliseconds to wait for any responses. The default is 3000.

  • num_initial_members specifies the maximum number of responses to wait for unless timeout has expired. The default is 2..

  • bind_addr specifies the interface on which to send and receive multicast packets.

  • bind_to_all_interfaces overrides the bind_addr and uses all interfaces in multihome nodes.

  • mcast_addr, mcast_port, ip_ttl attributes are the same as related attributes in the UDP protocol configuration.