Zero Packet Loss Ethernet Link Transition via Driver Fast Failover
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Adaptive Link Rate (ALR) in Ethernet networks causes packet loss due to link renegotiation, which is not yet supported by standard hardware or software solutions, impacting latency-sensitive applications with high latency and non-zero packet loss.
Innovation Solution
A data processing system with a primary network adapter in low power mode and a secondary adapter in high power mode, where the switch routes traffic to the primary adapter during low utilization and switches to the secondary adapter upon detecting high utilization, ensuring zero packet loss through driver fast failover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Adaptive Link Rate (ALR) renegotiates link speed during low utilization periods, then energy consumption is reduced, but packet loss occurs due to link reset taking several hundred milliseconds
Solution Approach 1:
The system performs preliminary actions by completing all in-process transmit requests over the primary adapter before switching to the secondary adapter. This ensures that no data is lost during the transition, as all pending transmissions are finalized beforehand. The switch is pre-configured with the MAC address of the active adapter, and the failover mechanism is prepared in advance to minimize disruption.
Solution Approach 2:
The invention introduces a secondary network adapter as an intermediary that remains in a low-power standby mode but is ready to immediately take over if the primary adapter fails or needs to be switched. This intermediary adapter allows for fast failover without the need for link renegotiation, thus preventing packet loss while still enabling energy savings when the primary adapter is operational.
2Use of energy by moving object
If link renegotiation is performed to switch between speed modes, then energy efficiency is improved, but latency increases due to several hundred milliseconds reset time
Solution Approach 1:
The system maintains the secondary adapter in a pre-initialized state with the MAC address already configured in the switch, so that when failover is needed, the transition can occur immediately without the several hundred milliseconds reset time associated with traditional link renegotiation. This preliminary configuration eliminates the latency penalty.
Solution Approach 2:
The system dynamically switches between two operational states: using the primary adapter for normal operation and switching to the secondary adapter when needed. The secondary adapter is kept in a dynamic standby mode that allows for immediate activation, creating a flexible system that can adapt to changing conditions without the latency overhead of full link renegotiation.
3Device complexity
If a single network adapter is used for both low power and high speed modes, then device complexity is reduced, but the ability to achieve zero packet loss during mode transitions is compromised
Solution Approach 1:
The system segments the network adapter functionality into two separate physical adapters: a primary adapter for low-power operation and a secondary adapter for high-speed operation. This segmentation allows each adapter to be optimized for its specific role while working together to provide both energy efficiency and reliability. The primary adapter handles normal traffic, while the secondary adapter stands by to immediately take over if needed, ensuring zero packet loss.
4Productivity
If the secondary adapter is activated in high speed mode, then throughput is improved for high utilization traffic, but power consumption increases
Solution Approach 1:
The system employs periodic monitoring of traffic utilization on the primary adapter. When utilization exceeds a threshold, the system transitions to using the secondary adapter for high-speed throughput. When utilization returns to normal levels, the system switches back to the primary adapter to save power. This periodic assessment and switching strategy ensures that high power consumption is only incurred when actually needed for high-throughput operations.
Data Source
AI summary
A mechanism for zero packet loss with energy efficient Ethernet link transition via driver fast failover is provided. By default, the mechanism uses a primary adapter running at low speed with low energy usage and a secondary adapter that is disabled. This default configuration is used during periods of low link utilization. When system or input/output load is such that high speed is required, then the mechanism enables the secondary adapter to its highest supported link speed. All transmit traffic in progress running over the primary adapter will complete, and upon completion, the driver generates an address resolution request and sends the request over the secondary adapter. After this process completes, the primary adapter transitions to link down and zero packet loss transition completes.