3com S7906E 설치 설명서

 

1-5 

Figure 1-4 Symmetric peers mode 

 

 

A device working in the symmetric active mode periodically sends clock synchronization messages, 

with the Mode field in the message set to 1 (symmetric active); the device that receives this message 

automatically enters the symmetric passive mode and sends a reply, with the Mode field in the message 

set to 2 (symmetric passive). By exchanging messages, the symmetric peers mode is established 

between the two devices. Then, the two devices can synchronize, or be synchronized by each other. If 

the clocks of both devices have been already synchronized, the device whose local clock has a lower 

stratum level will synchronize the clock of the other device. 

Figure 1-5 Broadcast mode 

Network

Client

Server

After receiving the first 

broadcast message, the 

client sends a request

Clock synchronization message 

exchange (Mode 3 and Mode 4)

Periodically broadcasts clock 

synchronization messages (Mode 5)

Calculates the network delay 

between client and the server 

and enters the broadcast 

client mode

Periodically broadcasts clock 

synchronization messages (Mode 5)

 Receives broadcast 

messages and synchronizes 

its local clock

 

 

In the broadcast mode, a server periodically sends clock synchronization messages to the broadcast 

address 255.255.255.255, with the Mode field in the messages set to 5 (broadcast mode). Clients listen 

to the broadcast messages from servers. After a client receives the first broadcast message, the client 

and the server start to exchange messages, with the Mode field set to 3 (client mode) and 4 (server 

mode) to calculate the network delay between client and the server. Then, the client enters the 

broadcast client mode and continues listening to broadcast messages, and synchronizes its local clock 

based on the received broadcast messages.