HP 5500 EI Series Configuration Manual page 24

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 other device.
Broadcast mode
Figure 9 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
broadcast messages from servers. When a client receives the first broadcast message, the client and the
server start to exchange messages with the Mode field set to 3 (client mode) and 4 (server mode), to
calculate the network delay between client and the server. Then, the client enters broadcast client mode.
The client continues listening to broadcast messages, and synchronizes its local clock based on the
received broadcast messages.
Multicast mode
Figure 10 Multicast mode
In multicast mode, a server periodically sends clock synchronization messages to the user-configured
multicast address, or, if no multicast address is configured, to the default NTP multicast address 224.0.1.1,
with the Mode field in the messages set to 5 (multicast mode). Clients listen to the multicast messages
from servers. When a client receives the first multicast message, the client and the server start to
exchange messages with the Mode field set to 3 (client mode) and 4 (server mode), to calculate the
network delay between client and server. Then, the client enters multicast client mode. It continues
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