H3C Technologies H3C S7500E Series Switches - Manual (Page 75)

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z In the symmetric mode, you should use the ntp-service refclock-master command or any
NTP configuration command in Configuring the Operation Modes of NTP to enable NTP;
otherwise, a symmetric-passive peer will not process NTP messages from a
symmetric-active peer.
z In the ntp-service unicast-peer command, ip-address must be a unicast address, rather
than a broadcast address, a multicast address or the IP address of the local clock.
z When the source interface for NTP messages is specified by the source-interface
argument, the source IP address of the NTP messages will be configured as the primary IP
address of the specified interface.
z Typically, at least one of the symmetric-active and symmetric-passive peers has been
synchronized; otherwise the clock synchronization will not proceed.
z 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 device working in NTP broadcast client
mode sends a reply and synchronizes its local clock.
For devices working in the broadcast mode, you need to configure both the server and clients.
Because an interface needs 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
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 device to work in
the NTP broadcast client mode
ntp-service broadcast-client Required