Physical Layer Timestamp and MACsec Processing
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Solution Overview
Problem
Security measures in communication networks, such as MACsec processing, often interfere with timestamp information, increasing uncertainty and making it difficult to maintain accurate timing without reducing bandwidth, which is challenging to address without compromising network security.
Innovation Solution
A physical layer communication device with a transmit chain including a timestamp processing block and a MACsec processing block that determines whether packets require timestamp processing, delays them if necessary to reduce inaccuracy, and performs MACsec operations, thereby minimizing the impact of security processing on timestamp accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MACsec security processing is applied to packets, then network security is improved, but timestamp accuracy deteriorates due to variable processing delays
Solution Approach 1:
The patent applies preliminary action by calculating and inserting the timestamp value into the packet before MACsec security processing is performed. This ensures that the timestamp reflects the actual transmission time without being affected by variable security processing delays, thereby maintaining timestamp accuracy while still applying security measures.
2Measurement precision
If packets are delayed to account for MACsec processing, then timestamp accuracy is improved, but bandwidth utilization deteriorates
Solution Approach 1:
The patent performs timestamp insertion before MACsec processing to eliminate the need for packet delays. By establishing the timestamp value in advance, the system achieves accurate timing without introducing bandwidth-wasting delays, thus resolving the contradiction between timestamp precision and bandwidth utilization.
3Reliability
If timestamp processing is performed after MACsec processing, then security is maintained, but timestamp inaccuracy increases due to variable delays
Solution Approach 1:
The patent reverses the conventional order by performing timestamp processing before MACsec security processing. This preliminary timestamp insertion captures the accurate transmission time, and subsequent security processing does not alter the timestamp value, thereby maintaining both security and timestamp accuracy simultaneously.
Data Source
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AI summary
A physical layer device provides both timestamp processing and security processing. The timestamp processing may be PTP processing according to IEEE Std. 1588 and/or OAM processing according to ITU-T Recommendation Y.1731. The security processing may be MACsec processing according to IEEE Std. 802.1AE. The timestamp processing may delay some packets to avoid impairing accuracy of timing information. For example, the accuracy of timing information could be impaired when a packet containing the timing information is delay due to additional bits added to a preceding packet to include a security tag and integrity check value.