ntp Flashcards
What protocol does RFC 958 introduce for synchronizing network clocks?
Network Time Protocol (NTP)
NTP is used in a distributed client/server architecture.
What type of protocol is NTP based on?
UDP-based protocol
NTP connects with servers on port 123.
What is the role of the NTP server in the synchronization process?
Operates as an authoritative time source with an atomic clock.
How does an NTP client synchronize its time?
By querying the NTP server and updating its time based on the response.
What is the maximum accuracy an NTP client can achieve?
Within a couple seconds of accuracy with a few cycles of polling.
What is required for an NTP client to achieve accuracy of tens of milliseconds?
Hours or days of comparisons.
What concept does NTP use to identify the accuracy of the time clock source?
Stratums.
What are stratum 1 servers in NTP?
NTP servers directly attached to an authoritative time source.
What is a stratum 2 client in NTP?
An NTP client that queries a stratum 1 server.
What is the relationship between NTP clients and NTP servers regarding time adjustment?
NTP clients change their time to match the NTP server’s time.
What is the purpose of NTP peers?
To blend their time to each other and act as backup devices.
What is the maximum rate at which NTP peers adjust their clocks?
Two minutes per query.
What does IEEE 1588-2002 define?
Precision Time Protocol (PTP).
Why was PTP created?
To provide clock synchronization for networked measurement and control systems.
What is the primary benefit of PTP in industrial networks?
More precise and accurate time synchronization.
What does PTP dynamically adjust to accommodate?
Device clocks in the network to handle packet delays.
What types of messages does PTPv2 use?
Event and General messages.
What is the purpose of the Announce message in PTP?
To determine which Grand Master is selected Best Master.
What is the function of the Follow_Up message in PTP?
To convey a captured timestamp of a transmitted SYNC message.
What is a boundary clock in PTP?
A device that exchanges messages between areas of the network.
What is the Sync message used for in PTP?
To convey time.
What is the default setting for PTP Boundary Mode?
Disabled.
What is the default setting for PTP Transparent Mode?
Enabled.
What is the default priority for PTP Priority1 and PTP Priority2?
128.
What is the default PTP Sync Interval?
1 Second.
Fill in the blank: PTP Announce Interval default setting is _______.
2 Seconds.
True or False: PTP is backward-compatible with regular PTP.
False.
