Ntp Operation Modes - HP 5820X Switch Configuration Manual

• Root Delay—Roundtrip delay to the primary reference source.
• Root Dispersion—Maximum error of the local clock relative to the primary reference source.
• Reference Identifier—Identifier of the particular reference source.
• Reference Timestamp—Local time at which the local clock was last set or corrected.
Originate Timestamp—Local time at which the request departed from the client for the service host.
•
Receive Timestamp—Local time at which the request arrived at the service host.
•
Transmit Timestamp—Local time at which the reply departed from the service host for the client.
•
Authenticator—Authentication information.
•

NTP operation modes

Devices that run NTP can implement clock synchronization in one of the following modes:
Client/server mode
•
Symmetric peers mode
•
Broadcast mode
•
Multicast mode
•
You can select operation modes of NTP as needed. If the IP address of the NTP server or peer is unknown
and many devices in the network must be synchronized, adopt the broadcast or multicast mode; while in
the client/server and symmetric peer modes, a device is synchronized from the specified server or peer,
and clock reliability is enhanced.
Client/server mode
Figure 21 Client/server mode
Performs clock filtering and
selection, and synchronizes its
local clock to that of the
optimal reference source
When working in client/server mode, a client sends a clock synchronization message to servers, with the
mode field in the message set to 3 (client mode). Upon receiving the message, the servers automatically
work in server mode and send a reply, with the Mode field in the messages set to 4 (server mode). Upon
receiving the replies from the servers, the client performs clock filtering and selection, and synchronizes its
local clock to that of the optimal reference source.
In client/server mode, a client can be synchronized to a server, but not vice versa.
Client
Network
Clock
synchronization
message
Reply ( Mode 4)
57
Server
Automatically works in
client/server mode and
(Mode3)
sends a reply