3Com 7757 Configuration Manual page 769

NTP Server Mode with
Authentication
Configuration
# Enter VLAN-interface 2 view.
[[SW7750-2] interface Vlan-interface 2
# Configure Switch 7750-2 to be a multicast client.
[SW7750-2-Vlan-Interface2] ntp-service multicast-client
The above configuration configures Switch 7750-1 and Switch 7750-2 to listen to
multicast packets through their VLAN interface 2, and 3Com3 to advertise
multicast packets through VLAN interface 2. Because Switch 7750-2 does not
reside in the same network segment with 3Com3, Switch 7750-2 cannot receive
multicast packets sent by 3Com3, while Switch 7750-1 is synchronized to 3Com3
after receiving multicast packets sent by 3Com3.
View the status of Switch 7750-1 after the synchronization.
[SW7750-1] display ntp-service status
Service status: enabled
Clock status: synchronized
Clock stratum: 3
Reference clock ID: 3.0.1.31
Nominal frequency: 250.0000 Hz
Actual frequency: 249.9992 Hz
Clock precision: 2^19
Clock offset: 198.7425 ms
Root delay: 27.47 ms
Root dispersion: 208.39 ms
Peer dispersion: 9.63 ms
Reference time: 17:03:32.022 UTC Thu Sep 6 2001 (BF422AE4.05AEA86C)
The output information indicates that Switch 7750-1 is synchronized to 3Com3,
with the clock stratum being 3, one stratum higher than 3Com3.
# View the information about the NTP sessions of Switch 7750-1 and you can see
that a connection is established between Switch 7750-1 and 3Com3.
[SW7750-1] display ntp-service sessions
source reference
**************************************************************************
[1]3.0.1.31 127.127.1.0
note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured
Network requirements
The local clock of Switch 7750-1 operates as the master NTP clock, with the clock
stratum being 2.
Switch 7750-2 operates in client mode with Switch 7750-1 as the time server.
Switch 7750-1 operates in the server mode automatically. Meanwhile, NTP
authentication is enabled on both sides.
Configuration Example
stra reach poll now offset
2 1 64 377 26.1
769
delay disper
199.53 9.7