H3C Technologies H3C SecBlade LB Cards - Manual (Page 124)

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The client continues listening to broadcast messages and synchronizes its local clock based on the
received broadcast messages.
Multicast mode
Figure 79 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
listening to multicast messages and synchronizes its local clock based on the received 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 operate in the specified NTP working mode only after
they 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 be implemented.
Configuring NTP in the Web interface
Configuring NTP
1. Select System > System Time from the navigation tree.
2. Click Network Time Protocol.
The page for configuring the network time appears.