Physical Link Layer Retransmission for Low Latency Reliability
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Solution Overview
Problem
Conventional physical link layer protocols, such as 10 Gigabit Ethernet, face latency issues due to the use of Forward Error Correction (FEC) for reliable data communication, which is detrimental in latency-sensitive applications like electronic trading systems, where delayed trade orders can affect execution prices.
Innovation Solution
Implementing a method that provides low latency data communication through repeated physical layer retransmission of data over idle connections, suppressing administrative control symbols to utilize bandwidth for redundancy and fault tolerance, and using sequence numbers or repeat indicators to distinguish original and repeat frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Forward Error Correction (FEC) is used for reliable data communication, then physical link layer reliability is improved, but latency increases due to complex processing overhead
Solution Approach 1:
The patent extracts the error correction function from the traditional FEC processing pipeline and implements it through a separate retransmission mechanism. Instead of correcting errors within the main data path using complex FEC algorithms, the system transmits redundant copies of data frames separately, allowing the receiver to simply select the first valid frame without time-consuming error correction processing.
Solution Approach 2:
The patent applies preliminary action by sending repeat frames in advance before the receiver needs the data. The transmitter sends multiple copies of the same data frame with different sequence numbers, ensuring that at least one copy arrives intact before the application layer requires the data, thereby eliminating the need for post-reception error correction.
2Speed
If FEC is disabled to reduce latency, then processing speed improves, but physical link layer reliability degrades
Solution Approach 1:
The patent uses copying by transmitting multiple identical copies of each data frame (repeat frames with same payload but different sequence numbers) without any error correction processing. The receiver simply needs to receive one valid copy, eliminating complex FEC operations while maintaining reliability through redundancy.
3Reliability
If administrative control symbols are transmitted continuously for receiver synchronization, then link reliability is maintained, but available bandwidth for data transmission decreases
Solution Approach 1:
The patent applies periodic action by transmitting administrative control symbols (idle and comma patterns) only periodically rather than continuously. During periods when no data is being transmitted, these synchronization symbols are sent to maintain receiver synchronization, but during active data transmission, bandwidth is dedicated entirely to data frames including repeat frames, maximizing throughput.
Data Source
AI summary
Systems and methods are disclosed herein that provide low latency data communication with improved physical link layer reliability through repeated physical layer retransmission of data over a data connection whenever the connection is idle (i.e., no new data to send). In some embodiments, the transmission of administrative control symbols (e.g. “idles,”“commas”, etc.) can be suppressed or otherwise reduced to allow some of the available connection bandwidth to be used for data redundancy and fault tolerance through the repeated retransmission of data as described in more detail below. Accordingly, instead of executing time-consuming error correcting routines, a receive node can discard the erroneous data frame and process at least one repeat frame that carries the same data payload. Sequence numbers and/or other repeat indicators can be used to distinguish original frames from repeat frames and/or for identifying which frames carry the same data payload.