R3204P16-HP Load Balancing Module System Management Configuration Guide-6PW101

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When working in client/server mode, a client sends a clock synchronization message to servers with the
Mode field in the message set to 3 (client mode). Upon receiving the message, the servers automatically
work in server mode and send a reply, with the Mode field in the messages set to 4 (server mode). Upon
receiving the replies from the servers, the client performs clock filtering and selection, and synchronizes
its local clock to that of the optimal reference source.
In client/server mode, a client can be synchronized to a server, but versa server cannot be synchronized
to a client.
Symmetric peers mode
Figure 56 Symmetric peers mode
In symmetric peers mode, devices that work in symmetric active mode and symmetric passive mode
exchange NTP messages with the Mode field 3 (client mode) and 4 (server mode). Then the device that
works in symmetric active mode periodically sends clock synchronization messages, with the Mode field
in the messages set to 1 (symmetric active). The device that receives the messages automatically enters
symmetric passive mode and sends a reply, with the Mode field in the message set to 2 (symmetric
passive). This exchange of messages establishes symmetric peers mode between the two devices, so the
two devices can synchronize, or be synchronized by, each other. If the clocks of both devices have been
synchronized, the device whose local clock has a lower stratum level synchronizes the clock of the other
device.
Broadcast mode
Figure 57 Broadcast mode
In broadcast mode, a server periodically sends clock synchronization messages to broadcast address
255.255.255.255, with the Mode field in the messages set to 5 (broadcast mode). Clients listen to the
Network
ClientServer
After receiving the first
broadcast message, the
client sends a request
Clock synchronization message
exchange (Mode 3 and Mode 4)
Periodically broadcasts clock
synchronization messages (Mode 5)
Calculates the network delay
between client and the server
and enters the broadcast
client mode
Periodically broadcasts clock
synchronization messages (Mode 5)
Receives broadcast
messages and synchronizes
its local clock