Network Time Sync Using TTL Path Detection
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Solution Overview
Problem
Existing time synchronization protocols in computer networks, such as PTP, face challenges in accurately adjusting the time of slave devices due to changes in network topology, leading to potential desynchronization and reduced accuracy.
Innovation Solution
The use of Time-To-Live (TTL) values in time synchronization messages allows slave devices to detect changes in the network path between master and slave devices, enabling adjustments to the time synchronization process to maintain accuracy and adapt to topology changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time synchronization protocols assume a symmetric network path between master and slave devices, then time synchronization can be performed using standard protocols, but network topology changes create asymmetric paths that cause desynchronization and reduce accuracy
Solution Approach 1:
The patent implements feedback by having the slave device monitor TTL values in incoming time synchronization messages and compare them against stored baseline values. When TTL changes are detected, the system automatically adjusts the time offset calculation to compensate for the asymmetric network path, thereby maintaining synchronization accuracy despite topology changes
Solution Approach 2:
The patent changes the parameter being monitored from merely time stamps to include TTL (Time To Live) values of network messages. By tracking TTL changes and using them to dynamically adjust time offset calculations, the system adapts to network topology changes while maintaining reliable time synchronization
2Adaptability or versatility
If the network path between master and slave devices changes, then the system can adapt to new routing conditions, but the time synchronization accuracy deteriorates due to asymmetric paths
Solution Approach 1:
The slave device continuously monitors TTL values in time synchronization messages and feeds this information back into the time offset calculation process. When TTL changes indicate a network path change, the system adjusts the time offset to compensate for the resulting asymmetry, maintaining measurement precision despite adaptability requirements
Solution Approach 2:
The TTL value acts as an intermediary parameter that mediates between network topology changes and time synchronization calculations. By using TTL as an intermediate indicator of path changes, the system can adjust time offsets accurately without directly measuring network asymmetry
Data Source
AI summary
In one example, network device includes a control unit having one or more hardware-based microprocessors and an interface. The interface can receive a first time synchronization message from a master device that comprises a first TTL value. The first TTL value can be indicative of a number of hops traversed by the first time synchronization message. The interface can subsequently receive a second time synchronization message from the master device that comprises a second TTL value that is is indicative of a number of hops traversed by the second time synchronization message. The network device can also include a timing module that determines a time adjustment based at least in part on the determination that the first and second TTL values are different, and applies the time adjustment to update the time of the network device.