Cut-Through Switching Error Detection in IEEE 802.1 TSN Networks
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Solution Overview
Problem
Cut-through switching methods in IEEE 802.1 Time Sensitive Networking (TSN) networks, used in real-time control applications like industrial automation and automotive networks, result in erroneous frames being forwarded due to the lack of error checking, leading to unacceptable latency and packet loss.
Innovation Solution
Incorporating an error detection mechanism using the source MAC address field in the data frame header, allowing for cut-through switching after successful error detection, and replacing the source MAC address with a cut-through switching field that includes a checksum and length information to ensure accurate forwarding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If cut-through switching method is used, then latency is reduced, but error checking is eliminated causing erroneous frames to be forwarded
Solution Approach 1:
The patent applies preliminary action by performing error detection on the data frame header before the switching decision is made. The switching device calculates a checksum of the header and compares it with an expected value to verify integrity prior to forwarding, thus preventing erroneous frames from being switched while maintaining low latency cut-through switching.
2Reliability
If error checking is performed in cut-through switching, then reliability is improved, but latency increases due to additional processing time
Solution Approach 1:
The patent segments the error checking process to apply it only to the header portion of the data frame rather than the entire frame. This selective error checking of the header field reduces the computational overhead and processing time while still providing sufficient error detection capability to ensure reliable forwarding decisions in cut-through switching.
3Reliability
If store-and-forward switching method is used, then error checking is performed, but latency increases due to waiting for complete frame reception
Solution Approach 1:
The patent applies preliminary action by performing error detection on the data frame header before the switching decision is made. The switching device calculates a checksum of the header and compares it with an expected value to verify integrity prior to forwarding, thus preventing erroneous frames from being switched while maintaining low latency cut-through switching.
Solution Approach 2:
The patent extracts the error checking function from the complete frame reception process and applies it specifically to the header portion. This extraction allows error detection to be performed on a smaller, critical subset of the data frame (the header) without waiting for the entire frame to be received, thereby reducing forwarding delay while maintaining reliability.
4Loss of time
If cut-through switching is used in IEEE 802.1 TSN networks, then low latency is achieved, but packet loss occurs due to erroneous frame forwarding
Solution Approach 1:
The patent applies preliminary action by performing error detection on the data frame header before the switching decision is made. The switching device calculates a checksum of the header and compares it with an expected value to verify integrity prior to forwarding, thus preventing erroneous frames from being switched while maintaining low latency cut-through switching required for real-time control applications.
Data Source
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AI summary
Embodiments include devices and methods for processing data packets including a data frame defined according to IEEE 802.1 Time Sensitive Networking standards. It is proposed to use the source MAC address field of the header of the so defined data frames in order to include an error detection mechanism that provides coverage for the header of the data frames. Thereafter, the cut-through switching method can be used in the forwarding process as soon as the destination MAC address of the data frame has been examined and error detection check on the header of the data frame is performed.