
Operation Manual – NTP
H3C S3610&S5510 Series Ethernet Switches
Chapter 1 NTP Configuration
1-10
Following these steps to configure a symmetric-active device:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Specify a
symmetric-passive
peer for the device
ntp-service
unicast-peer
[
vpn-instance
vpn-instance-name
] {
ip-address
|
peer-name
} [
authentication-keyid
keyid
|
priority
|
source-interface
interface-type interface-number
|
version
number
] *
Required
No
symmetric-passi
ve peer is
specified by
default.
Note:
z
In the symmetric mode, you should use any NTP configuration command in
Configuring the Operation Modes of NTP
to enable NTP; otherwise, a
symmetric-passive peer will not process NTP packets from a symmetric-active peer.
z
In the
ntp-service unicast-peer
command,
ip-address
must be a host address,
rather than a broadcast address, a multicast address or the IP address of the local
clock.
z
When the interface used to send NTP messages is specified by the
source-interface
argument, the source IP address of the NTP message 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.
1.3.3 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 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 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.