Hey, if you are here. You must have heard or wondering
about NTP at any point of time.
Yes, NTP stands for Network Time Protocol. Wait, but that is something we all know and familiar. So, what is new that we are here to learn on NTP?
NTP is in existence or introduced since 1985 to do the time synchronization, because time is something that can be easily overlooked, right? – Yes, but how NTP does that and most important why even NTP is critical to know for all of us?
OK, so let us see some theory on NTP –
NTP is an Internet Protocol (IP) again which is a networking protocol made for clock synchronization between devices in a network. It is probably one of the oldest protocols in place. It is an application layer protocol in an IP suite. NTP was originally designed / discovered / developed by David L Mills who was an American computer engineer. NTP is designed in a client-server model but also can be used in a peer-to-peer relationship (where peers consider other to be a potential time source) similarly as movies uTorrent sites work. NTP runs on UDP – User datagram protocol to send or receive time and operates on port 123. NTP’s current version is NTPv4. NTS – Network time security is an upgraded and secure version of NTP which works with TLS.
Let us see how it works and how NTP is helping to solve
the problem?
In a network, time variation even by just a few minutes can cause problems. Every device on a network has its own internal clock which tracks both time and date. We need to maintain a sync between all those devices time, otherwise it will be difficult to corelate logs, SSL certs and software licenses. A problem comes when a network keeps growing and maintaining the same time in every device becomes a nightmare. This is where NTP comes in to solve the problem.
NTP is always built in a hierarchal system. Each hierarchy or level is defined as a stratum and has been assigned a number with zero where zero means reference clock at the top of hierarchy.
Basically, the number represents the distance from the reference clock i.e., (stratum 0). This is a highly or most accurate time used in atomic clocks (where atoms absorb energy at a high energy state and works on oscillation at a certain frequency), GPS (Global positioning system), and radio-controlled time (where antenna is used to pass on the signals and a circuit is used to decode them).
What stratum means here? NTP uses the concept of stratum to define accuracy of the clock. Stratum range is between 0-15 where 0 means most accurate and 15 means least accurate. Any stratum value above 15 is not inline of accuracy.
Reference clocks with stratum 0 are directly connected to time servers also known as primary time servers which has stratum 1 and as it goes further down to stratum 2 time will be less accurate.
Please note that pool.ntp.org is an internet NTP server available which has stratum 1 or 2. Companies use their own internal GPS clock for more security reasons. We can make use of internet NTP server with configuration of its name server (DNS).
ntp status or ntp associations commands can be used to see the device clock synchronization, stratum value and IP address of that NTP server.
Yes, NTP stands for Network Time Protocol. Wait, but that is something we all know and familiar. So, what is new that we are here to learn on NTP?
NTP is in existence or introduced since 1985 to do the time synchronization, because time is something that can be easily overlooked, right? – Yes, but how NTP does that and most important why even NTP is critical to know for all of us?
NTP is an Internet Protocol (IP) again which is a networking protocol made for clock synchronization between devices in a network. It is probably one of the oldest protocols in place. It is an application layer protocol in an IP suite. NTP was originally designed / discovered / developed by David L Mills who was an American computer engineer. NTP is designed in a client-server model but also can be used in a peer-to-peer relationship (where peers consider other to be a potential time source) similarly as movies uTorrent sites work. NTP runs on UDP – User datagram protocol to send or receive time and operates on port 123. NTP’s current version is NTPv4. NTS – Network time security is an upgraded and secure version of NTP which works with TLS.
In a network, time variation even by just a few minutes can cause problems. Every device on a network has its own internal clock which tracks both time and date. We need to maintain a sync between all those devices time, otherwise it will be difficult to corelate logs, SSL certs and software licenses. A problem comes when a network keeps growing and maintaining the same time in every device becomes a nightmare. This is where NTP comes in to solve the problem.
NTP is always built in a hierarchal system. Each hierarchy or level is defined as a stratum and has been assigned a number with zero where zero means reference clock at the top of hierarchy.
Basically, the number represents the distance from the reference clock i.e., (stratum 0). This is a highly or most accurate time used in atomic clocks (where atoms absorb energy at a high energy state and works on oscillation at a certain frequency), GPS (Global positioning system), and radio-controlled time (where antenna is used to pass on the signals and a circuit is used to decode them).
What stratum means here? NTP uses the concept of stratum to define accuracy of the clock. Stratum range is between 0-15 where 0 means most accurate and 15 means least accurate. Any stratum value above 15 is not inline of accuracy.
Reference clocks with stratum 0 are directly connected to time servers also known as primary time servers which has stratum 1 and as it goes further down to stratum 2 time will be less accurate.
Please note that pool.ntp.org is an internet NTP server available which has stratum 1 or 2. Companies use their own internal GPS clock for more security reasons. We can make use of internet NTP server with configuration of its name server (DNS).
ntp status or ntp associations commands can be used to see the device clock synchronization, stratum value and IP address of that NTP server.
Any thoughts? Please let me know in the comments.
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