1-8
z In the symmetric peer mode, you need to execute the related NTP configuration commands (refer
to Configuring NTP Implementation Modes for details) to enable NTP on a symmetric-passive peer;
otherwise, the symmetric-passive peer will not process NTP messages from the symmetric-active
peer.
z The remote device specified by remote-ip or peer-name serves as the peer of the local device, and
the local device works in the symmetric-active mode. In this case, the clock of the local device and
that of the remote device can be synchronized to each other.
z remote-ip must not be a broadcast address, a multicast address or the IP address of the local
clock.
z After you specify an interface for sending NTP messages through the source-interface keyword,
the source IP address of the NTP message will be configured as the IP address of the specified
interface.
z Typically, the clock of at least one of the symmetric-active and symmetric-passive peers should be
synchronized first; otherwise the clock synchronization will not proceed.
z You can configure multiple symmetric-passive peers for the local device by repeating the
ntp-service unicast-peer command. The clock of the peer with the smallest stratum will be
chosen to synchronize with the local clock of the device.
Configuring NTP Broadcast Mode
For devices working in the broadcast mode, you need to configure both the server and clients. The
broadcast server periodically sends NTP broadcast messages to the broadcast address
255.255.255.255. The devices working in the NTP broadcast client mode will respond to the NTP
messages, so as to start the clock synchronization.
The device can work as a broadcast server or a broadcast client.
A broadcast server can synchronize broadcast clients only after its clock has been synchronized.

Configuring the device to work in the NTP broadcast server mode

To do… Use the command… Remarks
Enter system view system-view —
Enter VLAN interface view interface Vlan-interface
vlan-id —
Configure the device to work in
the NTP broadcast server
mode
ntp-service broadcast-server
[ authentication-keyid key-id |
version number ]*
Required
Not configured by default.