Network Flow Control Using Queue-Specific Congestion Notifications
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Solution Overview
Problem
Current network flow control methods, such as source flow control (SFC), lack precise identification of the source network device associated with congestion, leading to inaccurate flow control operations and high buffer requirements in congested network devices.
Innovation Solution
A network flow control method that includes generating and sending flow control notifications with specific device, port, and queue information to ensure accurate flow control operations by identifying the correct network device, port, and queue for flow control execution, thereby avoiding incorrect operations and reducing buffer requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If source flow control (SFC) is implemented using only source IP address for route lookup, then flow control can be triggered for congestion management, but the identification of the source network device becomes imprecise leading to incorrect flow control operations
Solution Approach 1:
The patent segments the identification process by separating the source IP address lookup from the final flow control target identification. It introduces intermediate identification steps using port information and queue information that are extracted and transmitted through congestion notification packets. This segmentation allows the system to progressively narrow down from a broad IP address to a specific network device, port, and queue combination, thereby resolving the imprecision in source identification while maintaining reliable flow control operations.
2Reliability
If link-level flow control (PFC) is used to manage congestion between directly connected network devices, then local congestion can be controlled, but congestion propagates upward layer by layer causing widespread network congestion
Solution Approach 1:
The patent introduces congestion notification packets as intermediary carriers that transport critical flow control information (port information, queue information, device identification) across multiple network hops. These packets act as mediators between the congested network device and the source network device, enabling direct communication of congestion status without triggering widespread PFC pauses. This intermediary mechanism allows precise flow control to be implemented at the source while maintaining overall network productivity.
3Measurement precision
If flow control notifications include detailed device, port, and queue information, then accurate flow control operations can be performed, but the complexity of the flow control system increases
Solution Approach 1:
The patent implements a universal congestion notification packet structure that can carry multiple types of identification information (device ID, port information, queue information) in a standardized format. This multi-functional packet design allows the same notification mechanism to serve various flow control scenarios without requiring separate protocols for each level of precision. The universal structure reduces system complexity by providing a single, flexible solution that adapts to different identification needs while maintaining high precision in flow control target identification.
Data Source
AI summary
A network flow control method includes: a first network device receives a target packet from a second network device, where the target packet carries packet flow control information, and the packet flow control information includes identification information of the second network device, information about a port from which the target packet flows into the second network device, information about a queue in which the target packet is located in the second network device, and/or priority information of the target packet. The first network device determines that the second network device needs to perform a flow control operation, then generates a first flow control notification based on the packet flow control information. The first network device sends the first flow control notification to the second network device, where the first flow control notification indicates the second network device to perform the flow control operation.