H3C Technologies H3C S3600 Series Switches - Manual (Page 875)

1-8
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.
Follow these steps to configure a symmetric-active switch:
To do… Use the command… Remarks
Enter system view system-view —
Specify a
symmetric-passive
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.
z In the symmetric peer mode, you need to execute the related NTP configuration commands (refer
to section 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 Ethernet
switch, and the local switch works in the symmetric-active mode. In this case, the clock of the local
switch 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 switch 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 switch.
Configuring NTP Broadcast Mode
For switches 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 switches working in the NTP broadcast client mode will respond to the NTP
messages, so as to start the clock synchronization.
An H3C S3600 series Ethernet switch can work as a broadcast server or a broadcast client.