3Com Switch 8800 Advanced Software V5 Configuration Guide

NTP Configuration Examples 1079
Clock precision: 2^7
Clock offset: -21.1982 ms
Root delay: 15.00 ms
Root dispersion: 775.15 ms
Peer dispersion: 34.29 ms
Reference time: 15:22:47.083 UTC Sep 19 2005 (C6D95647.153F7CED)
As shown above, Device B has been synchronized to Device C, and the clock
stratum level of Device B is 2, while that of Device C is 1.
# View the NTP session information of Device B, which shows that an association
has been set up between Device B and Device C.
[DeviceB] display ntp-service sessions
source reference stra reach poll now offset delay disper
**************************************************************************
[245] 3.0.1.31 127.127.1.0 2 15 64 24 10535.0 19.6 14.5
[1234] 3.0.1.33 LOCL 1 14 64 27 -77.0 16.0 14.8
note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured
Total associations : 2
Configuring NTP
Broadcast Mode
Network requirements
Switch C’s local clock is to be used as a reference source, with the stratum level of
2, and Switch C sends out broadcast messages from VLAN-interface 2. Switch D
and Switch A listen to broadcast messages through their own VLAN-interface 2
and VLAN-interface 3 respectively.
Network diagram
Figure 316 Network diagram for NTP broadcast mode configuration
Configuration procedure
1 Configuration on Switch C:
# Specify the local clock as the reference source, with the stratum level of 2.
<SwitchC> system-view
[SwitchC] ntp-service refclock-master 2
# Configure to send broadcast messages through VLAN-interface 2.
Vlan-int3
1.0.1.11/24
Vlan-int3
1.0.1 .10/24
Vlan-int2
3.0.1.31/24
Vlan-int2
3.0.1.32/24
Vlan-int2
3.0.1.30/24
Switch A Switch B
Switch C
Switch D