3com 5500-ei pwr Instrução De Instalação

 

1-2 

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Defining the accuracy of clocks by stratum to synchronize the clocks of all devices in a network 

quickly 

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Supporting access control (see section 

) and MD5 encrypted 

authentication (see section 

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Sending protocol packets in unicast, multicast, or broadcast mode 

 

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The clock stratum determines the accuracy, which ranges from 1 to 16. The stratum of a reference 

clock ranges from 1 to 15. The clock accuracy decreases as the stratum number increases. A 

stratum 16 clock is in the unsynchronized state and cannot serve as a reference clock. 

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The local clock of an S5500-EI Ethernet switch cannot be set as a reference clock. It can serve as 

a reference clock source to synchronize the clock of other devices only after it is synchronized. 

 

 shows the implementation principle of NTP. 

Ethernet switch A (Device A) is connected to Ethernet switch B (Device B) through Ethernet ports. Both 

having their own system clocks, they need to synchronize the clocks of each other through NTP. To help 

you to understand the implementation principle, we suppose that: 

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Before the system clocks of Device A and Device B are synchronized, the clock of Device A is set 

to 10:00:00 am, and the clock of Device B is set to 11:00:00 am. 

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Device B serves as the NTP server, that is, the clock of Device A will be synchronized to that of 

Device B. 

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It takes one second to transfer an NTP message from Device A to Device B or from Device B to 

Device A.