H3C Technologies H3C SR8800 - Manual (Page 71)

59
Configuring the NTP symmetric mode
For routers working in the symmetric mode, you need to specify a symmetric-passive on a symmetric-active
peer.
To configure a symmetric-active router:
Step Command Remarks
1. Enter system view. system-view N/A
2. Specify a symmetric-passive
peer for the router.
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 ] *
No symmetric-passive peer is
specified by default.
NOTE:
•
In symmetric peers 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.
• 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.
• When the source interface for NTP messages is specified by the source-interface argument, the source
IP address of the NTP message is configured as the primary IP address of the specified interface.
• Typically, at least one of the symmetric-active and symmetric-passive peers has been synchronized;
otherwise the clock synchronization will not proceed.
• 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 router working in NTP broadcast mode sends a
reply and synchronizes its local clock.
For routers 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.
Configuring a broadcast client
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface view.
interface interface-type
interface-number Enter the interface used to receive
NTP broadcast messages