Server Congestion Window Control via ACK Feedback
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Solution Overview
Problem
Current IP networks lack effective congestion control mechanisms, particularly in providing Quality of Service (QoS) guarantees, leading to inefficient bandwidth management and potential network congestion due to the absence of central monitoring and dynamic link availability.
Innovation Solution
Implementing a method for a server device to set and manage a congestion window, using novel start, feedback control, and fast recovery algorithms to detect and control congestion, ensuring the effective window size remains above a minimum bandwidth threshold and adjusting based on packet loss causes, such as congestion or physical failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If IP networks employ fairness principle to share bandwidth equally among devices, then bandwidth distribution is improved, but network congestion control capability deteriorates
Solution Approach 1:
The patent changes the parameter of window size from a fixed equal-share value to a dynamically adjusted value based on ACK feedback. The congestion window is incremented selectively based on whether ACKs are duplicate or non-duplicate, allowing the system to adapt bandwidth allocation to actual network conditions rather than enforcing rigid equality.
Solution Approach 2:
The patent implements feedback control by monitoring ACK packets from receiver devices. When non-duplicate ACKs are received, the congestion window is incremented, allowing increased bandwidth usage. When only duplicate ACKs are received, the window remains constrained. This feedback mechanism enables dynamic congestion control while maintaining fair bandwidth distribution.
2Difficulty of detecting and measuring
If IP networks detect congestion using packet loss and RTT, then congestion detection capability is improved, but QoS guarantee capability deteriorates
Solution Approach 1:
The patent substitutes the traditional mechanical congestion detection method (reacting to packet loss and RTT increases) with a proactive window adjustment mechanism based on ACK feedback. Instead of waiting for congestion symptoms to manifest through packet loss, the system proactively adjusts the congestion window based on ACK patterns, preventing congestion before it causes QoS degradation.
3Reliability
If source devices adjust window size to control data quantity upon congestion detection, then congestion control is improved, but bandwidth utilization efficiency deteriorates
Solution Approach 1:
The patent implements dynamic window size adjustment where the congestion window is incremented based on ACK feedback patterns. The window size is not statically reduced upon congestion detection but is dynamically adjusted in real-time based on whether ACKs are duplicate or non-duplicate, allowing the system to maintain high bandwidth utilization while effectively controlling congestion.
Solution Approach 2:
The patent maintains continuous useful action by keeping the congestion window in a state of gradual increment based on ACK feedback. Rather than abruptly reducing the window size upon congestion detection, the system continuously adjusts the window to optimize bandwidth utilization, ensuring that data transmission remains efficient while congestion is controlled.
Data Source
AI summary
The disclosure includes a method of performing congestion control by a server device in a network. The method includes setting an effective window equal to a congestion window; sending traffic including the effective window to a client device; receiving an acknowledgment (ACK) from the client device; incrementing the congestion window if the ACK is not a duplicate; and updating the effective window based at least partly on the incremented congestion window.