Multiple Instances Of Ntp - HP 5820X Switch Configuration Manual

Multicast mode
Figure 24 Multicast mode
In multicast mode, a server periodically sends clock synchronization messages to the user-configured
multicast address, or, if no multicast address is configured, to the default NTP multicast address 224.0.1.1,
with the Mode field in the messages set to 5 (multicast mode). Clients listen to the multicast messages
from servers. When a client receives the first multicast 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 multicast client mode and continues listening to
multicast messages, and synchronizes its local clock based on the received multicast messages.
NOTE:
In symmetric peers mode, broadcast mode and multicast mode, the client (the symmetric active peer)
and the server (the symmetric passive peer) can only work in the specified NTP working mode after they
exchange NTP messages with the Mode field being 3 (client mode) and the Mode field being 4 (server
mode). During this message exchange process, NTP clock synchronization can be implemented.

Multiple instances of NTP

The client/server mode and symmetric mode support multiple instances of NTP and support clock
synchronization within an MPLS VPN network. Network devices—CEs and PEs—at different physical
location can get their clocks synchronized through NTP, as long as they are in the same VPN. The
following functions are available:
• NTP client on a CE can be synchronized to the NTP server on another CE.
NTP client on a CE can be synchronized to the NTP server on a PE.
•
NTP client on a PE can be synchronized to the NTP server on a CE through a designated VPN
•
instance.
NTP client on a PE can be synchronized to the NTP server on another PE through a designated VPN
•
instance.
NTP server on a PE can synchronize the NTP clients on multiple CEs in different VPNs.
•
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