3Com 4500 Configuration Manual page 558

Network diagram
Figure 1-9 Network diagram for NTP multicast mode configuration
Configuration procedure
Configure Device C.
# Enter system view.
<DeviceC> system-view
# Set Device C as a multicast server to send multicast messages through VLAN-interface 2.
[DeviceC] interface Vlan-interface 2
[DeviceC-Vlan-interface2] ntp-service multicast-server
Configure Device A (perform the same configuration on Device D).
# Enter system view.
<DeviceA> system-view
# Set Device A as a multicast client to listen to multicast messages through VLAN-interface 2.
[DeviceA] interface Vlan-interface 2
[DeviceA-Vlan-interface2] ntp-service multicast-client
After the above configurations, Device A and Device D respectively listen to multicast messages
through their own VLAN-interface 2, and Device C advertises multicast messages through
VLAN-interface 2. Because Device A and Device C do not share the same network segment, Device A
cannot receive multicast messages from Device C, while Device D is synchronized to Device C after
receiving multicast messages from Device C.
View the NTP status of Device D after the clock synchronization.
[DeviceD] display ntp-service status
Clock status: synchronized
Clock stratum: 3
Reference clock ID: 3.0.1.31
Nominal frequency: 100.0000 Hz
Actual frequency: 100.0000 Hz
Clock precision: 2^18
Clock offset: 198.7425 ms
Root delay: 27.47 ms
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