Time Protocol facts for kids

The Time Protocol is a special set of rules for computers to talk to each other. It was created in 1983 by Jon Postel and K. Harrenstein. Its main job is to help computers get the correct date and time from a central server. This way, all computers can have the same time, no matter where they are.

This protocol can work using two different ways of sending data: Transmission Control Protocol (TCP) or User Datagram Protocol (UDP). When a computer wants to know the time, it connects to a server that uses the Time Protocol. This connection happens on a specific "door" or port, which is number 37.

Once connected, the server sends the time back. This time is a number that shows how many seconds have passed since midnight on January 1, 1900, Greenwich Mean Time (GMT). It's a 32-bit number, which means it's a long string of ones and zeros. After sending the time, the server closes the connection. If UDP is used, there's no connection setup; the computer just sends a small message to the server's port 37, and the server replies with the time.

Time Protocol's Limit

The Time Protocol uses a 32-bit number to count seconds. This means it can only count up to a certain point. After about 136 years, the number "rolls over" or resets. The first time this will happen is on February 7, 2036. Computers that still use this old protocol need to be smart enough to figure out if the time they get is from 1900 or 2036.

Why We Use Newer Protocols

Many older Unix-like computer systems used the Time Protocol to check or set their clocks. They often used a tool called `rdate` for this. However, a newer and much better protocol called the Network Time Protocol (NTP) came along. NTP is more advanced because it can tell time much more precisely, even down to tiny fractions of a second, not just whole seconds. Because of this, NTP and its tools (like `ntpdate`) replaced the older Time Protocol for keeping computer clocks accurate.

See also

In Spanish: Time Protocol para niños

• Echo Protocol
• Discard Protocol
• Daytime Protocol
• Character Generator Protocol
• rdate, a tool for querying the current time from a network server