Blocking Shaper for AVB Latency Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current non-arbitrary networks fail to meet latency requirements for high-priority data transmission, particularly over wireless connections, as they are unable to transmit Class A frames within the specified time limits set by IEEE 802.1 AVB standards, especially at Fast Ethernet speeds.
Innovation Solution
A network device with memory queues and a timing module that generates priority timing signals, along with deblocking and blocking shapers, is used to manage and prioritize data transmission, ensuring that high-priority frames are transmitted within allocated time periods and minimizing latency by preventing interference from lower-priority frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data transmission is allowed during allocated time periods without blocking, then network utilization is improved, but latency requirements for high-priority Class A frames are not met
Solution Approach 1:
The blocking shaper performs preliminary blocking of lower-priority frames before the allocated transmission time period begins. This pre-action ensures that when Class A frames need to transmit during their allocated time, the transmission path is already clear, preventing any latency while maintaining high network utilization during non-allocated periods.
Solution Approach 2:
The system implements periodic blocking and unblocking of frames based on allocated time periods. During Class A allocated time, lower-priority frames are blocked; during non-allocated time, they are unblocked for transmission. This periodic action pattern ensures latency requirements are met while maximizing overall network productivity.
2Loss of time
If blocking is applied to prevent lower-priority frame interference, then latency for high-priority data is reduced, but network device complexity increases
Solution Approach 1:
The blocking shaper changes the temporal parameter of frame transmission by applying time-based blocking control. Instead of complex structural modifications, the system uses parameter changes (blocking/unblocking based on time allocation) to reduce latency, thereby achieving the desired effect with minimal increase in device complexity.
3Loss of time
If Class A frames are transmitted during allocated time periods, then latency requirements are met, but lower-priority data transmission is delayed
Solution Approach 1:
The system uses periodic blocking and unblocking to manage frame transmission. Lower-priority frames are blocked only during Class A allocated time periods and are unblocked during non-allocated periods for transmission. This periodic action ensures Class A latency requirements are met while providing guaranteed transmission opportunities for lower-priority data, balancing the duration of action for different frame types.
Data Source
AI summary
A network device including first and second queues, a timing module and a shaper. The first queue receives first frames. The second queue receives second frames. A priority level of the second frames is lower than a priority level of the first frames. The timing module determines a start time of a burst period of the first frames. The first frames are transmitted from the network device during the burst period. The shaper determines: a size of a head-of-line frame of the second frames; a predetermined maximum size of one of the second frames; or a predetermined minimum size of one of the second frames. The shaper determines whether to block transmission of the head-of-line frame from the network device based on (i) the start time, (ii) the size of the head-of-line frame, (iii) the predetermined maximum size, or (iv) the predetermined minimum size.