Time-Aware Blocking Shaper for IEEE 802.1Qbv Latency
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Solution Overview
Problem
Current data communication networks face challenges in efficiently transmitting packets with different priority levels, particularly in preventing interference between high-priority and low-priority data transmissions, which can lead to increased latency and jitter.
Innovation Solution
Implementing time-aware blocking shapers in network devices that block low-priority data during a predetermined blocking band at the start of a transmission interval, allowing low-priority data to be transmitted only after high-priority data has been transmitted, ensuring minimal interference and efficient use of transmission time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If low-priority data is transmitted during the blocking band period, then the utilization of transmission time is improved, but high-priority data transmission is interfered with causing increased latency
Solution Approach 1:
The transmission interval is segmented into distinct phases: a blocking band at the beginning where only high-priority data can be transmitted, and a subsequent phase where both high-priority and low-priority data may be transmitted. This segmentation ensures high-priority data gets dedicated transmission time while low-priority data utilizes remaining capacity, resolving the contradiction between transmission utilization and latency.
Solution Approach 2:
The blocking band is established as a preliminary action at the start of each transmission interval to clear the transmission medium of low-priority data before high-priority data transmission begins. This preliminary blocking prevents interference and ensures deterministic latency for high-priority traffic while still allowing efficient use of remaining transmission time.
2Loss of time
If low-priority data is blocked during the entire transmission interval, then high-priority data latency is minimized, but overall network productivity decreases
Solution Approach 1:
Instead of blocking low-priority data for the entire transmission interval (excessive action), the blocking is applied only to the necessary blocking band duration (partial action). This allows high-priority data to achieve deterministic latency while low-priority data can still transmit during the remaining interval, maintaining overall network productivity.
Solution Approach 2:
The blocking band is applied periodically at the start of each transmission interval, creating a rhythmic pattern of exclusive high-priority transmission followed by shared transmission. This periodic structure ensures consistent latency bounds for high-priority data while maximizing throughput by allowing low-priority data transmission during non-blocking periods.
3Productivity
If multiple priority levels are transmitted simultaneously without blocking, then transmission efficiency is improved, but jitter increases due to interference between priority levels
Solution Approach 1:
The transmission medium is segmented in time with a blocking band dedicated to high-priority data, separating it from low-priority data transmission. This temporal segmentation eliminates interference and jitter caused by simultaneous multi-priority transmission while maintaining efficiency by allowing low-priority data to use the remaining transmission capacity.
Data Source
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AI summary
A network device including a plurality of queues configured to store respective frames of data having a priority level. The network device includes a shaper configured to transmit, during a first portion of a transmission interval, frames of data from a first one of the plurality of queues having a highest priority level, block frames of data from a second one of the plurality of queues during a blocking band extending from a first time prior to a start of the transmission interval to a second time indicating the start of the transmission interval, determine, based on the second time and a maximum frame size to be transmitted during the transmission interval, the second time, and selectively transmit, subsequent to the first time and prior to the second time, frames of data from the second one of the plurality queues based on the second time.