Network Time Protocol (NTP)

Part 1: Understanding Time Synchronization

Why Do We Need NTP?

1. Computer clocks tend to drift over time
2. Different devices need to agree on the exact time for:
3. Coordinating events
4. Logging activities
5. Securing network communications
6. Scheduling tasks

How NTP Works

Client-Server Model

• Your device (client) asks specialized time servers (NTP servers) for the current time
• The server responds with highly accurate time information
• Your device adjusts its clock accordingly

Time Server Hierarchy

• Level 0: Atomic clocks and GPS clocks (Stratum 0)
• Level 1: Computers directly connected to Level 0 devices
• Level 2: Computers that get time from Level 1

Part 2: Basic NTP Communication

The NTP Request Process

1. Your device sends a tiny message to an NTP server
2. The server adds its timestamp
3. Your device calculates the time difference, accounting for network delay
4. Your clock gets adjusted

Understanding Time Formats

1. NTP uses seconds since January 1, 1900
2. Modern computers use seconds since:
3. January 1, 1970 (Unix time)
4. January 1, 2000 (Some embedded systems)
5. We need to convert between these formats