H3C Technologies H3C S7500E Series Switches - Manual (Page 85)

3-21
Clock precision: 2^18
Clock offset: 0.0000 ms
Root delay: 31.00 ms
Root dispersion: 1.05 ms
Peer dispersion: 7.81 ms
Reference time: 14:53:27.371 UTC Sep 19 2005 (C6D94F67.5EF9DB22)
As shown above, Device B has been synchronized to Device A, and the clock stratum level of
Device B is 3, while that of Device A is 2.
# View the NTP session information of Device B, which shows that an association has been set
up between Device B and Device A.
[DeviceB] display ntp-service sessions
source reference stra reach poll now offset delay disper
**************************************************************************
[12345] 1.0.1.11 127.127.1.0 2 63 64 3 -75.5 31.0 16.5
note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured
Total associations : 1
Configuring the NTP Symmetric Mode
Network requirements
Perform the following configurations to synchronize time among devices:
z The local clock of Device A is to be configured as a reference source, with the stratum level
of 2.
z Device B works in the client mode and Device A is to be used as the NTP server of Device
B.
z Device C works in the symmetric-active mode and Device B will act as peer of Device C.
Device C is the symmetric-active peer while Device B is the symmetric-passive peer.
Figure 3-8 Network diagram for NTP symmetric peers mode configuration
Switch A
Switch B Switch C
3.0.1.31/24
3.0.1.32/24 3.0.1.33/24
Configuration procedure
1) Configure IP addresses for interfaces (omitted).
2) Configuration on Device A:
# Specify the local clock as the reference source, with the stratum level of 2.
<DeviceA> system-view
[DeviceA] ntp-service refclock-master 2