Transfer Apparatus Low-Latency Frame Timing Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Transfer apparatuses in industrial Ethernet networks face increased latency when transferring low-latency frames from low-speed input ports to high-speed output ports, as they must store frame data to prevent underrun and determine if normal-latency frames can be divided, leading to undesirable latency time for low-latency frames.
Innovation Solution
A transfer apparatus with low-latency and normal-latency frame transmission buffers, a time calculation unit, and an output contention control unit that calculates the output start time of low-latency frames and controls their transfer, allowing for prioritization and minimizing latency by starting low-latency frame output at the calculated time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frame data is stored to prevent underrun when transferring from low-speed input port to high-speed output port, then underrun is prevented, but transfer latency of low-latency frames increases
Solution Approach 1:
The patent applies preliminary action by calculating the output start time of low-latency frames in advance based on input line speed, output line speed, and frame length. The transfer apparatus determines when to start outputting the low-latency frame before actual transfer begins, allowing the system to prepare timing information proactively. This enables the low-latency frame to be output as soon as sufficient data is accumulated, minimizing waiting time while ensuring underrun prevention through advance timing calculation.
2Loss of time
If normal-latency frame transfer is suspended to output low-latency frame, then low-latency frame latency is reduced, but normal-latency frame transfer is delayed
Solution Approach 1:
The patent applies partial action by suspending normal-latency frame transfer only for the minimum necessary duration to output the low-latency frame. The system calculates the exact output start time and suspends normal traffic only during the critical period when low-latency frame transmission is required. After the low-latency frame is output, normal-latency frame transfer resumes, thus applying interruption only partially rather than continuously, minimizing the impact on normal traffic while ensuring low-latency frame priority.
3Stability of the object's composition
If low-latency frame output is delayed until normal-latency frame transfer completes, then normal-latency frame transfer continuity is maintained, but low-latency frame latency increases undesirably
Solution Approach 1:
The patent applies dynamics by making the transfer apparatus adaptive and flexible in handling different frame types. The system dynamically adjusts transfer behavior based on frame priority: low-latency frames are output immediately when sufficient data is accumulated, while normal-latency frames are suspended only when necessary. The transfer continuity is maintained through dynamic timing calculation that adapts to varying input/output line speeds and frame lengths, allowing the system to switch between priority handling and continuity maintenance as needed.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A transfer apparatus has an input port and an output port, an input line speed of the input port and an output line speed of the output port being capable of being set to differ from each other. The transfer apparatus comprises, for each output port: a low-latency frame transmission buffer (15) to store a low-latency frame received at the input port; a normal-latency frame transmission buffer (16) to store a normal-latency frame that is a frame received at the input port, the normal-latency frame being permitted to be transferred with higher latency than the low-latency frame; a time calculation unit (21) to calculate output start time of the low-latency frame by using information on a frame length of the low-latency frame, the input line speed, and the output line speed when the low-latency frame is received; and an output contention control unit (23) to control transfer of the low-latency frame and the normal-latency frame by using the output start time.