Flow-Specific Quotas for Last-Hop Buffer Congestion Control
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Solution Overview
Problem
Existing congestion management mechanisms, such as ECN, are inefficient in handling diverse congestion scenarios and can incorrectly throttle non-contributing traffic, leading to inconsistencies and increased execution times in communication networks.
Innovation Solution
A dynamic quota-based congestion management system that determines the fraction of available buffer space at a last-hop switch and adjusts packet forwarding based on this quota and the response rate of the receiver node, thereby avoiding buffer overflow and ensuring efficient packet forwarding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ECN-based congestion management is used, then congestion control is provided, but non-contributing traffic is incorrectly throttled leading to inconsistencies and increased execution times
Solution Approach 1:
The patent segments the shared buffer into multiple queues, one for each flow, and implements independent quota management for each queue. This segmentation allows the system to track buffer usage per-flow rather than globally, preventing incorrect throttling of non-contributing traffic while maintaining accurate congestion control for actual contributors.
Solution Approach 2:
The patent implements feedback mechanisms where the network device monitors buffer occupancy levels and dynamically adjusts transmission quotas for each flow based on current buffer status. This feedback loop ensures that congestion control decisions are based on real-time conditions, improving accuracy while avoiding unnecessary throttling of flows that are not contributing to congestion.
2Productivity
If buffer space is shared among multiple flows, then resource utilization is improved, but congestion management becomes inconsistent across different flows
Solution Approach 1:
The patent divides the shared buffer into multiple flow-specific queues with individual quota counters. Each flow receives a fair share of buffer resources through its dedicated queue, maintaining resource utilization efficiency while ensuring consistent congestion management policies are applied uniformly across all flows through the standardized quota validation mechanism.
Solution Approach 2:
The patent applies local quality by allowing each flow queue to have its own quota allocation and validation rules tailored to its specific characteristics, while the overall buffer management maintains global consistency through the centralized quota-based control mechanism. This enables differentiated treatment of different flows while maintaining overall system stability.
3Measurement precision
If dynamic quota adjustment is implemented, then congestion control accuracy is improved, but system complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-calculating and allocating buffer quotas to each flow before congestion occurs. The quota-based framework is established in advance, allowing the system to make simple quota validation decisions during operation rather than complex real-time calculations, thus improving measurement precision while limiting the increase in system complexity.
Solution Approach 2:
The patent uses parameter changes by dynamically adjusting quota values based on buffer occupancy levels and flow characteristics. The system changes the quota parameter in response to congestion conditions, enabling accurate congestion detection through simple threshold comparisons rather than complex algorithms, thus improving precision while managing complexity.
Data Source
AI summary
A system for facilitating sender-side congestion control is provided. During operation, the system, on a sender node, can determine the utilization of a buffer at a last-hop switch to a receiver node based on in-flight packets to the receiver node. The receiver node can be reachable from the sender node via the last-hop switch. The system can then determining a fraction of available space in the buffer for packets from the sender node based on the utilization of the buffer. Subsequently, the system can determine whether the fraction of the available space in the buffer can accommodate a next packet from the sender node while avoiding congestion at the buffer at the receiver node. If the fraction of the available space in the buffer can accommodate the next packet, the system can allow the sender node to send the next packet to the receiver node.