Time Protocol facts for kids

The Time Protocol is like a special language computers use to tell each other the exact time. It's part of a bigger set of rules called the Internet Protocol Suite, which helps all devices on the internet talk to each other. The main goal of the Time Protocol is to give computers a way to find out the correct date and time, no matter where they are in the world.

How the Time Protocol Works

Computers can use the Time Protocol in two main ways: through Transmission Control Protocol (TCP) or User Datagram Protocol (UDP). Imagine you want to know the time from a special time server.

• Using TCP: Your computer connects to the time server on a specific "door" called port 37. Once connected, the server sends back the time. It sends it as a special number, which is the total number of seconds that have passed since midnight on January 1, 1900, Greenwich Mean Time (GMT). After sending the time, the server closes the connection.
• Using UDP: With UDP, your computer just sends a quick message to the server's port 37. There's no long connection setup. The server then sends the time back in the same special number format.

The time is sent as a 32-bit number. This means it's a number made of 32 ones and zeros. This number represents how many seconds have passed since January 1, 1900.

Understanding the Time Rollover

Because the time is sent as a 32-bit number, there's a limit to how high that number can go. This means that the Time Protocol's clock "rolls over" or resets about every 136 years. The first time this rollover will happen is on 7 February 2036.

When this happens, computers using the Time Protocol need to be smart. They must use other information, like the current year, to figure out if the time they received is from the 1900s or from the 2030s.

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 much more advanced system called the Network Time Protocol (NTP) is used today.

NTP is better than the Time Protocol in many ways. For example, NTP can tell the time much more precisely, even down to tiny fractions of a second, not just whole seconds. This makes NTP much more accurate for keeping computer clocks perfectly in sync.

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