Time synchronization over the Internet using an adaptive frequency-locked loop

Area of Science:

• Computer Science
• Network Engineering
• Distributed Systems

Background:

• Accurate time synchronization is crucial for distributed systems and network operations.
• Existing algorithms for network time synchronization face challenges with cost, bandwidth usage, and adaptability to network conditions.

Purpose of the Study:

• To describe a self-configuring algorithm for synchronizing computer times over packet-switched networks.
• To achieve a specified performance level at minimum cost (computer cycles or network bandwidth).
• To improve upon existing time synchronization methods in terms of accuracy, cost-efficiency, and bandwidth utilization.

Main Methods:

• The algorithm employs a pure frequency-locked loop (FLL) with unequal spacing between calibration cycles.
• It self-configures to balance accuracy and cost, adapting to network delay asymmetry.
• Performance is limited by local clock oscillator instability or measurement noise, achieving ~8 ms RMS with standard hardware.

Main Results:

• The algorithm achieves a trade-off between cost and accuracy, with cost inversely proportional to accuracy squared.
• It utilizes network bandwidth more efficiently than previous methods by employing a pure FLL.
• Demonstrates improved adaptability to network delay fluctuations compared to prior algorithms.

Conclusions:

• The developed algorithm offers a cost-effective and adaptable solution for network time synchronization.
• Its design, using a pure FLL and self-configuration, enhances performance and bandwidth efficiency.
• The algorithm provides a cleaner separation of network and clock noise, crucial for high-accuracy synchronization.