3com 8807 User Guide

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NTP Configuration
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By default, no broadcast service is configured and the version number number 
defaults to 3.
This command can only be configured on the interface where the NTP broadcast 
packets will be transmitted.
Configuring NTP Broadcast Client Mode
Designate an interface on the local Switch to receive NTP broadcast messages and 
operate in broadcast client mode. The local Switch listens to the broadcast from 
the server. When it receives the first broadcast packets, it starts a brief client/server 
mode to switch messages with a remote server for estimating the network delay. 
Thereafter, the local Switch enters broadcast client mode and continues listening 
to the broadcast and synchronizes the local clock according to the broadcast 
message that arrived .
Perform the following configuration in VLAN interface view.
This command can only be configured on the interface where the NTP broadcast 
packets will be received.
Configuring NTP Multicast Server Mode
Designate an interface on the local Switch to transmit NTP multicast packets. In 
this case, the local equipment operates in Multicast mode and serves as a 
Multicast server to multicast messages to its clients regularly.
Perform the following configuration in VLAN interface view.
NTP version number number ranges from 1 to 3 and defaults to 3; the 
authentication key ID keyid ranges from 1 to 4294967295; ttl-number of the 
multicast packets ranges from 1 to 255; And the multicast IP address defaults to 
224.0.1.1. Actually, for the Switch 8800 Family series, you can set 224.0.1.1 as the 
multicast IP address only.
 This command can only be configured on the interface where the NTP multicast 
packet will be transmitted.
Table 702   Configure NTP broadcast client mode
Operation 
Command 
Configure NTP broadcast client mode 
ntp-service broadcast-client 
Disable NTP broadcast client mode 
undo ntp-service broadcast-client
Table 703   Configure NTP Multicast server mode
Operation 
Command 
Configure NTP Multicast 
server mode 
ntp-service multicast-server [ ip-address ] [ 
authentication-keyid keyid | ttl ttl-number | version 
number ]* 
Cancel NTP Multicast server 
mode 
undo ntp-service multicast-server [ ip-address ]