Configuring the Operation Modes of NTP 955
■ Typically, at least one of the symmetric-active and symmetric-passive peers has 
been synchronized; otherwise the clock synchronization will not proceed.
■ You can configure multiple symmetric-passive peers by repeating the 
ntp-service unicast-peer command.
Configuring NTP
Broadcast Mode
The broadcast server periodically sends NTP broadcast messages to the broadcast 
address 255.255.255.255. After receiving the messages, the switch working in 
NTP broadcast mode sends a reply and synchronizes its local clock.
For switches working in the broadcast mode, you need to configure both the 
server and clients. Because an interface need to be specified on the broadcast 
server for sending NTP broadcast messages and an interface also needs to be 
specified on each broadcast client for receiving broadcast messages, the NTP 
broadcast mode can be configured only in the specific interface view.
Configuring a broadcast client
Configuring the broadcast server
n
A broadcast server can synchronize broadcast clients only after its clock has been 
synchronized.
Configuring NTP
Multicast Mode
The multicast server periodically sends NTP multicast messages to multicast clients, 
which send replies after receiving the messages and synchronize their local clocks.
For switches working in the multicast mode, you need to configure both the server 
and clients. The NTP multicast mode must be configured in the specific interface 
view.
Configuring a multicast client
To do…  Use the command…  Remarks 
Enter system view  system-view - 
Enter interface view  interface interface-type 
interface-number 
Required
Enter the interface used to 
receive NTP broadcast 
messages 
Configure the switch to work 
in the NTP broadcast client 
mode 
ntp-service 
broadcast-client 
Required
To do…  Use the command…  Remarks 
Enter system view  system-view - 
Enter interface view  interface interface-type 
interface-number 
Enter the interface used to 
send NTP broadcast messages 
Configure the switch to work 
in the NTP broadcast server 
mode 
ntp-service 
broadcast-server 
[ authentication-keyid keyid 
| version number ]* 
Required
To do…  Use the command…  Remarks 
Enter system view  system-view -