1-7Multicast modeFigure 1-6 Multicast modeNetworkClientServerAfter receiving the firstmulticast message, theclient sends a requestClock synchronization messageexchange (Mode 3 and Mode 4)Periodically multicasts clocksynchronization messages (Mode 5)Calculates the network delaybetween client and the serverand enters the multicastclient modePeriodically multicasts clocksynchronization messages (Mode 5) Receives multicastmessages and synchronizesits local clockIn the multicast mode, a server periodically sends clock synchronization messages to theuser-configured multicast address, or, if no multicast address is configured, to the default NTP multicastaddress 224.0.1.1, with the Mode field in the messages set to 5 (multicast mode). Clients listen to themulticast messages from servers. After a client receives the first multicast message, the client and theserver start to exchange messages, with the Mode field set to 3 (client mode) and 4 (server mode) tocalculate the network delay between client and the server. Then, the client enters the multicast clientmode and continues listening to multicast messages, and synchronizes its local clock based on thereceived multicast messages.In symmetric peers mode, broadcast mode and multicast mode, the client (or the symmetric active peer)and the server (the symmetric passive peer) can work in the specified NTP working mode only afterthey exchange NTP messages with the Mode field being 3 (client mode) and the Mode field being 4(server mode). During this message exchange process, NTP clock synchronization can beimplemented.NTP Configuration Task ListComplete the following tasks to configure NTP:Task RemarksConfiguring the Operation Modes of NTP RequiredConfiguring Optional Parameters of NTP OptionalConfiguring Access-Control Rights OptionalConfiguring NTP Authentication Optional
