Single-Step PTP Timestamp Selection for Variable Latency
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Solution Overview
Problem
Single-step Precision Time Protocol (PTP) packets face challenges due to variable latency in hardware data paths, affecting timestamp accuracy and clock synchronization between electronic devices, which can impact device functionality.
Innovation Solution
An integrated circuit system with programmable logic circuitry and transceiver tiles generates multiple encrypted copies of PTP packets with different timestamps, compares them to a time-of-day value, and selects the closest one for transmission, compensating for variable latency in the data path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If single-step PTP is used to send timestamp within sync message, then clock synchronization speed is improved, but timestamp accuracy deteriorates due to variable latency in hardware data path
Solution Approach 1:
The system performs preliminary actions by generating multiple copies of the PTP packet with different predicted timestamps before transmission. These copies are created in advance based on predicted latency values, allowing the receiving end to select the most accurate timestamp without waiting for actual latency measurement, thus resolving the contradiction between fast synchronization and accurate timestamping.
Solution Approach 2:
The system changes the timestamp parameter by generating multiple PTP packet copies with different timestamp values corresponding to different predicted latency scenarios. Instead of using a single timestamp, the system varies the timestamp parameter across multiple copies, enabling selection of the most accurate one at the receiving end while maintaining single-step PTP speed advantages.
2Measurement precision
If multiple copies of PTP packets with different timestamps are generated and encrypted, then timestamp accuracy is improved, but device complexity increases
Solution Approach 1:
The system creates multiple copies of the PTP packet with different predicted timestamps based on historical latency data. These copies are then encrypted and transmitted, allowing the receiving end to select the most accurate timestamp without requiring complex real-time latency measurement and compensation mechanisms, thus improving timestamp accuracy while keeping device complexity manageable.
3Reliability
If encryption is applied to PTP packets for security, then security is improved, but processing time increases
Solution Approach 1:
The system performs encryption as a preliminary action during the packet generation phase, creating multiple encrypted copies of PTP packets with different timestamps before transmission. By completing encryption in advance rather than performing it in real-time at the transmitting or receiving end, the system maintains security while minimizing the time impact on the critical timestamp synchronization process.
Data Source
AI summary
Systems or methods of the present disclosure may provide an integrated circuit system including programmable logic circuitry and a transceiver tile coupled to the programmable logic circuitry, the transceiver tile including a transceiver subsystem. The transceiver subsystem may be configurable to store a precision time protocol (PTP) packet, generate a first copy of the PTP packet with a first timestamp, a second copy of the PTP packet with a second timestamp, and a third copy of the PTP packet with a third timestamp, encrypt each of the first copy of the PTP packet, the second copy of the PTP packet, and the third copy of the PTP packet, and transmit either the first copy of the PTP packet, the second copy of the PTP packet, or the third copy of the PTP packet.