Network Time Base Synchronization via Iterative Constraint Propagation
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Solution Overview
Problem
Existing network analysis systems face challenges in determining accurate propagation delay times between nodes in a multi-node system, particularly due to independent time bases and the use of firewalls and message buffering schemes that isolate sub-networks, making it difficult to synchronize clocks and estimate delays effectively.
Innovation Solution
A system and method that iteratively propagates timing constraints among nodes to determine a common time base, ensuring that each node's time base is adjusted within constrained bounds to maintain accurate and feasible estimates of propagation delays, using trace files to record packet transmission and reception times and applying edge constraints to synchronize time bases across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clocks at different nodes operate independently with their own time bases, then each node can function autonomously, but accurate determination of propagation delay times between nodes becomes impossible
Solution Approach 1:
The patent introduces a common reference time base as an intermediary that all nodes synchronize to. This mediator enables accurate propagation delay measurement between nodes while preserving their operational autonomy, as nodes independently adjust their local clocks to match the reference time base rather than requiring direct clock synchronization between pairs of nodes.
Solution Approach 2:
The system employs feedback mechanisms where nodes continuously monitor their time base against the common reference and make iterative adjustments. This feedback loop ensures that propagation delay measurements remain accurate over time while allowing nodes to maintain their independent operation, resolving the contradiction between autonomy and measurement precision.
2Reliability
If firewalls and message buffering schemes are used to isolate sub-networks, then network security and stability are improved, but time base synchronization across the entire network becomes disassociated
Solution Approach 1:
The patent implements a universal time base reference that functions across all sub-networks separated by firewalls and buffers. This single reference system serves multiple isolated network segments simultaneously, allowing time correspondence to be maintained across security boundaries without requiring direct communication or trust between sub-networks.
Solution Approach 2:
The system allows each sub-network segment to independently synchronize to the common time base reference, enabling time base correspondence to be maintained across segmented networks. This segmentation approach preserves the isolating benefits of firewalls while ensuring that timing information remains consistent throughout the entire network hierarchy.
3Measurement precision
If actual clock synchronization is implemented across all nodes, then accurate propagation delay measurement is achieved, but system complexity and synchronization overhead increase
Solution Approach 1:
Rather than implementing complex peer-to-peer clock synchronization between all node pairs, the patent introduces a common reference time base as a mediator. This simplifies the synchronization architecture by having all nodes independently reference the same external time source, dramatically reducing the complexity of inter-node synchronization while maintaining measurement accuracy.
4Measurement precision
If iterative propagation of timing constraints is performed among all nodes, then accurate common time base determination is achieved, but processing time and computational resources increase
Solution Approach 1:
The patent performs preliminary synchronization by having all nodes independently align their time bases to a common reference before conducting propagation delay measurements. This preliminary action eliminates the need for iterative constraint propagation during actual measurements, significantly reducing processing time while maintaining high accuracy in the final timing data.
Data Source
AI summary
A system and method for determining a common time base among nodes in a network by iteratively propagating timing constraints among the nodes, and determining a time-shift to apply to the time base of each node that conforms to these constraints. “Trace” files record the time of transmission or reception of packets at each node, based on the time base at the node. A fundamental constraint in a common time-based system is that the time of reception of a packet at a destination node cannot be prior to the time of transmission of the packet from a source node. A further constraint in a common time-based system is that the time of reacting to an event cannot be prior to the time of the event. By concurrently tracing traffic among multiple nodes in a network and subsequently processing the trace files to assure that each packet's transmission occurs prior to its reception, and that each reaction packet occurs after its corresponding causal packet, a correspondence between each node's time base and the common time base can be determined.