Operation Manual – NTP
H3C S3100 Series Ethernet Switches Chapter 1 NTP Configuration
1-8
 Note:
z The remote server specified by remote-ip or server-name serves as the NTP server,
and the local switch serves as the NTP client. The clock of the NTP client will be
synchronized by but will not synchronize that of the NTP server.
z remote-ip cannot 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 primary IP address of the specified interface.
z A switch can act as a server to synchronize the clock of other switches only after its
clock has been synchronized. If the clock of a server has a stratum level lower than
or equal to that of a client’s clock, the client will not synchronize its clock to the
server’s.
z You can configure multiple servers by repeating the ntp-service unicast-server
command. The client will choose the optimal reference source.
1.3.2 Configuring the NTP Symmetric Peer Mode
For switches working in the symmetric peer mode, you need to specify a
symmetric-passive peer on the symmetric-active peer.
Table 1-4 Configure a symmetric-active switch
Operation Command Description
Enter system view
system-view
—
Specify a
symmetric-passiv
e peer for the
switch
ntp-service unicast-peer
{ remote-ip | peer-name }
[ authentication-keyid key-id |
priority | source-interface
Vlan-interface vlan-id | version
number ]*
Required
By default, a switch is not
configured to work in the
symmetric mode.