Clock Synchronization via Path Filtering Against Delay Attacks
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Solution Overview
Problem
Clock synchronization protocols in packet-based networks are vulnerable to delay attacks, where malicious entities can disrupt synchronization by adding delay to packets, leading to inaccurate network latency measurements and improper synchronization between master and slave clocks.
Innovation Solution
A network device is equipped with multiple communication paths and a clock synchronization module that determines path time data sets, identifies inaccurate data sets based on accuracy metrics, and calculates the time of day using reliable path data sets, thereby mitigating the impact of delay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple communication paths are used for clock synchronization, then reliability against delay attacks is improved, but device complexity increases
Solution Approach 1:
The patent divides the clock synchronization process into multiple independent path measurements. Each communication path is treated as a separate segment with its own time dataset, allowing the system to evaluate and select reliable paths individually rather than treating all paths as a single unit. This segmentation enables the slave clock to identify and exclude compromised paths while maintaining synchronization through reliable paths.
Solution Approach 2:
The patent introduces a new dimension of path diversity by utilizing multiple communication paths between master and slave clocks. Instead of relying on a single synchronization channel, the system measures time datasets across multiple dimensional paths, creating redundancy that allows detection and mitigation of delay attacks through comparative analysis of path-specific timing data.
2Measurement precision
If path time data sets are filtered based on accuracy metrics, then measurement precision is improved, but loss of information increases
Solution Approach 1:
The patent extracts and removes inaccurate path time datasets from the synchronization calculation based on accuracy metrics. By identifying datasets that fail to meet precision thresholds and excluding them from the final time determination, the system improves overall measurement precision while consciously accepting the loss of potentially compromised information as a necessary trade-off for reliability.
Solution Approach 2:
The patent changes the parameter of data set inclusion by dynamically adjusting which path time datasets are used based on accuracy evaluation. Instead of using all available paths uniformly, the system modifies the effective dataset composition by excluding paths that demonstrate timing anomalies or exceed acceptable deviation thresholds, thereby optimizing precision at the cost of utilizing fewer data points.
Data Source
AI summary
In a network device communicatively coupled to a master clock via a plurality of different communication paths, a clock synchronization module is configured to determine a plurality of path time data sets corresponding to the plurality of different communication paths based on signals received from the master clock via the plurality of different communication paths between the network device and the master clock. A clock module is configured to determine that at least one of the plurality of path time data sets is inaccurate based on accuracy metrics corresponding to the plurality of path time data sets, and determine a time of day as a function of a remainder of one or more path time data sets, in the plurality of path time data sets, not determined to be inaccurate. The device may detect and/or mitigate “man-in-the-middle” attacks aimed at a clock synchronization protocol.