3Com WX3000 Series Operation Manual page 480

Multicast mode
Figure 1-5 Multicast mode
Server
Works in the server mode
automatically and sends
responses
Table 1-1 describes how the above mentioned NTP modes are implemented on the device.
Table 1-1 NTP implementation modes on the device
NTP implementation
mode
Server/client mode
Symmetric peer mode
Broadcast mode
Multicast mode
When the device works in server mode or symmetric passive mode, you need not to perform
related configurations on this device but do that on the client or the symmetric-active peer.
The NTP server mode, NTP broadcast mode, or NTP multicast mode takes effect only after the
local clock of the device has been synchronized.
When symmetric peer mode is configured on two devices, to synchronize the clock of the two
devices, make sure at least one device's clock has been synchronized.
Network
Multicast clock synchronization
packets periodically
Client/server mode
request
Response
Multicast clock synchronization
packets periodically
Configure the local device to work in the NTP client mode. In this mode,
the remote server serves as the local time server, while the local device
serves as the client.
Configure the local device to work in NTP symmetric peer mode. In this
mode, the remote server serves as the symmetric-passive peer of the
device, and the local device serves as the symmetric-active peer.
Configure the local device to work in NTP broadcast server mode. In
this mode, the local device broadcasts NTP messages through the
VLAN interface configured on the device.
Configure the device to work in NTP broadcast client mode. In this
mode, the local device receives broadcast NTP messages through the
VLAN interface configured on the device.
Configure the local device to work in NTP multicast server mode. In
this mode, the local device sends multicast NTP messages through
the VLAN interface configured on the device.
Configure the local device to work in NTP multicast client mode. In this
mode, the local device receives multicast NTP messages through the
VLAN interface configured on the device.
1-5
Client
Initiates a client/server mode
request after receiving the
first multicast packet
Obtains the delay between the
client and server and works in
the multicast client mode
Receives multicast packets and
synchronizes the local clock
Configuration on the device