Ethernet Congestion Control via Dynamic Rate Regulation
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Solution Overview
Problem
Conventional router fabric designs using proprietary ASICs are expensive, scalable, and unsuitable for data center environments, where high-quality, reliable network performance is required, especially in scenarios sensitive to latency and congestion, such as high-frequency trading and cloud computing.
Innovation Solution
The Ethernet Congestion Control and Prevention (ECCP) system continuously probes network paths to estimate available bandwidth and regulate traffic, maintaining a minimal available bandwidth margin to prevent congestion, allowing for scalable and efficient network management without modifying Ethernet bridges, focusing on end-hosts to control transmission rates and prevent frame queueing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If proprietary ASIC devices are used in conventional router fabric designs, then network characteristics such as guaranteed packet delivery, low delay, and consistent jitter are achieved, but cost increases and scalability is limited
Solution Approach 1:
The patent replaces expensive proprietary ASIC devices with standard Ethernet switches and implements congestion control algorithms (ECN, PFC, QCN) that copy the functionality of specialized chips through software-based mechanisms, achieving similar reliability without the cost and scalability limitations of hardware-specific solutions
Solution Approach 2:
The patent substitutes hardware-based congestion control mechanisms in proprietary ASICs with software-based Ethernet protocols and algorithms running on standard switches, replacing mechanical/hardware systems with flexible software implementations that maintain packet delivery guarantees while improving scalability
2Ease of manufacture
If standard Ethernet technology is used instead of specialized chips, then cost is reduced and integration with DC fabric is improved, but frame delivery guarantee and congestion control capabilities are lost
Solution Approach 1:
The patent implements feedback-based congestion control mechanisms where Ethernet switches monitor network conditions and send congestion notifications (ECN marks, PFC pauses, QCN feedback) back to source devices, enabling dynamic adjustment of transmission rates to maintain frame delivery guarantees on standard Ethernet infrastructure
Solution Approach 2:
The patent applies preliminary congestion control actions by marking packets with ECN bits or sending PFC pause frames before actual buffer overflow occurs, preventing congestion proactively and ensuring frame delivery guarantees are maintained through advance intervention rather than reactive measures
3Ease of operation
If Ethernet PAUSE is used for congestion control, then link-level flow control is achieved, but end-to-end congestion control and fairness among multiple flows are not provided
Solution Approach 1:
The patent segments congestion control into multiple layers: link-level PAUSE for immediate flow control and end-to-end protocols (ECN, QCN) for comprehensive congestion management across multiple switches, combining local and global control mechanisms to achieve both ease of operation and end-to-end adaptability
Solution Approach 2:
The patent merges link-level PAUSE control with end-to-end congestion control protocols, combining the simplicity of local flow control with the comprehensive coverage of network-wide congestion management to achieve both ease of operation and end-to-end fairness among multiple flows
4Productivity
If link utilization is increased to maximize bandwidth capacity, then network throughput is improved, but congestion and packet loss occur
Solution Approach 1:
The patent uses feedback-based congestion control where switches monitor queue depths and buffer utilization, and dynamically adjust transmission rates by sending ECN marks or PFC pause frames back to sources, enabling the network to operate near maximum capacity while preventing packet loss through continuous monitoring and adjustment
Solution Approach 2:
The patent implements dynamic congestion control that continuously adapts transmission rates based on real-time network conditions, allowing link utilization to fluctuate near capacity limits while maintaining reliability through dynamic adjustment of flow rates rather than static conservative limits
Data Source
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AI summary
Switch fabric in routers require tight characteristics in term of packet loss, fairness in bandwidth allocation and low latency for high-priority traffic. Such attributes have been resolved using specialized switch devices, but with the emergence of Data Center Bridging, the possibility of using commodity Ethernet switches to build switch fabric in routers is considered. Systems and methods are provided for adjusting a data transmission rate in accordance with an estimation of network path utilization.