Key-Flow Back-Pressure Control in Switching Devices
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Solution Overview
Problem
Existing flow control mechanisms, such as Priority-based Flow Control (PFC), cause congestion diffusion, reduce throughput rate, and increase average delay, leading to degraded network performance due to indiscriminate pausing of data flows across the network.
Innovation Solution
A method and device that identify a 'key flow' causing congestion and selectively pause only that flow using back pressure frames, while allowing other flows to continue, thereby reducing congestion diffusion and packet loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PFC mechanism sends back pressure frames to all input ports causing congestion, then congestion is controlled at the source, but congestion diffusion occurs and network performance degrades
Solution Approach 1:
The patent segments the network traffic into different data flows and identifies only the 'key flow' causing congestion. Instead of pausing all flows, the back pressure frame contains flow identification information that targets only the specific key flow, segmenting the control action from the entire network traffic to just the problematic flow.
Solution Approach 2:
The patent applies local quality by making the flow control action selective rather than uniform. The back pressure frame includes flow identification information that enables downstream devices to pause only the specific key flow while allowing other non-key flows to continue transmission, creating localized control quality differentiated by flow type.
2Reliability
If PFC mechanism pauses all data flows at upstream devices, then congestion is prevented at the source, but average delay increases and network performance decreases
Solution Approach 1:
The patent segments the data flows into key flows and non-key flows, applying pause actions only to key flows. The back pressure frame contains flow identification information that enables selective pausing, so non-key flows experience no delay while key flows are paused only when necessary to prevent congestion.
Solution Approach 2:
The patent applies different quality of service treatment to different flows locally. Non-key flows maintain normal transmission without delay, while key flows receive paused treatment only when congestion is detected. This local differentiation minimizes overall network delay while preventing congestion.
3Reliability
If back pressure frames are sent to all upstream switching devices, then congestion is controlled network-wide, but device complexity and control overhead increase
Solution Approach 1:
The patent segments the control information in back pressure frames by including only flow identification information related to key flows. This segmentation reduces the amount of control data that upstream devices must process compared to traditional mechanisms that would require handling all flows, simplifying device complexity while maintaining network-wide congestion control.
Data Source
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AI summary
The present invention discloses a flow control method, including: when congestion is detected, determining, by a first switching device, a key flow from a plurality of data flows; generating a back pressure message including a flow attribute value of the key flow; sending the back pressure message to an upstream device of the key flow; and pausing, by the upstream device of the key flow, sending of the key flow, where the back pressure message has no impact on sending of another data flow other than the key flow by the upstream device of the key flow. The present invention further provides a switching device that can implement the flow control method. According to the present invention, congestion can be effectively alleviated, packet loss can be avoided, and congestion diffusion can be effectively controlled, thereby improving network data exchange performance.