H3C Technologies H3C SecBlade NetStream Cards - Manual (Page 210)

195
Multicast mode
Figure 60 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 the server. Then, the client enters multicast client mode and continues
listening to multicast messages, and synchronizes its local clock based on the received multicast
messages.
NOTE:
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 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.
NTP configuration task list
Complete the following tasks to configure NTP:
Task Remarks
Configuring the operation modes of NTP Required
Configuring optional parameters of NTP Optional
Configuring NTP authentication Optional
Configuring the operation modes of NTP
The NetStream card can implement clock synchronization in the client/server mode. In this mode, you
need to configure only clients.