3Com Switch 4500 26-Port, Configuration Manual

Page: 308 / 396

306 C
HAPTER
18: NTP C
ONFIGURATION
# Enter system view.
<SW4500-2> system-view
[SW4500-2]
# Enter Vlan-interface2 view.
[SW4500-2] interface Vlan-interface 2
[SW4500-2-Vlan-interface2]
# Set SW4500-2 to a broadcast client.
[SW4500-2-Vlan-interface2] ntp-service broadcast-client
After the above configurations, SW4500-1 and SW4500-2 will listen to broadcast
packets through their own Vlan-interface2, and Switch3 will send broadcast
packets through Vlan-interface2. Because SW4500-2 and Switch3 do not share
the same network segment, SW4500-2 cannot receive broadcast packets from
Switch3, while SW4500-1 is synchronized to Switch3 after receiving broadcast
packets from Switch3.
View the status of SW4500-1 after synchronization.
[SW4500-1] display ntp-service status
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 SW4500-1 is synchronized to Switch3, with
the clock stratum level of 3, one level lower than that of Switch3.
# View the information about the NTP sessions of SW4500-1 and you can
see that a connection is established between SW4500-1 and Switch3.
[SW4500-1] display ntp-service sessions
source reference stra reach poll now offset delay disper
**************************************************************************
[1]3.0.1.31 127.127.1.0 2 1 64 377 26.1 199.53 9.7
note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured
Configuring NTP
Multicast Mode
Network requirements
The local clock of Switch3 is set to the NTP master clock, with a clock stratum level
of 2. Switch3 advertises multicast packets through Vlan-interface2.
SW4500-1 and SW4500-2 respectively listen to multicast packets through their
own Vlan-interface2.
This example assumes that Switch3 is a switch that supports the local clock being
the master clock.