Programmable Network Device Event Injection for Hardware Stack Analysis

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Solution Overview

Problem

Hardware network stack implementations are difficult to test and analyze due to their 'black box' nature, making it challenging for engineers to evaluate and compare their behavior on different devices, especially since conventional tools lack flexibility and cannot analyze fine-grained device behavior.

Innovation Solution

A method using a programmable network device to inject events into network traffic and mirror the traffic for analysis, allowing for deterministic event injection and precise, reproducible tests without modifying the underlying hardware, utilizing a configuration file or GUI to specify event parameters and analyze the behavior of network stack functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If network stack functionality is implemented in hardware, then processing speed and throughput are improved, but testability and analyzability deteriorate due to black box nature

Engineering Contradiction:

Improvenetwork processing speedVSAvoiddifficulty of testing and analyzing network stack behavior

Core Design Contradiction:

SpeedVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces a programmable network device as an intermediary component between the hardware network stack and the testing environment. This device can inject events into network traffic and mirror traffic for analysis, enabling external observation and control of the black box hardware network stack without modifying its internal implementation, thus resolving the contradiction between hardware acceleration and testability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a copy of the network traffic through mirroring functionality in the programmable network device. This copied traffic can be analyzed externally to understand the behavior of the hardware network stack without interfering with the original high-speed processing, allowing detailed analysis while maintaining processing performance

Inventive Principle:

Principle #26Copying

2Ease of manufacture

If conventional testing tools are used on hardware network stack, then implementation simplicity is maintained, but measurement precision and analysis capability deteriorate

Engineering Contradiction:

Improvesimplicity of implementationVSAvoidprecision of network stack behavior analysis

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The programmable network device serves as an enhanced intermediary that provides fine-grained control over event injection and traffic mirroring. This allows precise measurement of network stack behavior including retransmission logic, latency, and congestion notification, while maintaining a relatively simple overall system architecture that builds upon conventional testing approaches

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent enables precise control of testing parameters through the programmable network device, allowing engineers to inject specific events with controlled timing, frequency, and types. This parameter control capability enables precise measurement of network stack responses under various controlled conditions, significantly improving measurement precision over conventional tools

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If detailed analysis of network stack behavior is performed, then measurement precision is improved, but processing time and system complexity increase

Engineering Contradiction:

Improvedetail of network stack behavior analysisVSAvoidadditional delay in testing and analysis

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent mirrors network traffic to create analysis copies that can be examined in detail without affecting the original high-speed data plane processing. This separation allows comprehensive analysis of network stack behavior including fine-grained timing measurements while the original traffic flows through the hardware network stack at full line rate, minimizing time loss

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The programmable network device operates continuously at full line rate, injecting events and mirroring traffic without interrupting or slowing down the original network flow. This continuous operation ensures that detailed analysis can be performed on mirrored traffic while the primary network processing maintains its high throughput and low latency characteristics

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS20240056361A1Event injection for analysis of hardware network stack behavior

Publication Date: 2024.02.15 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

This document relates to analyzing of network stack functionality that is implemented in hardware, such as on a network adapter. The disclosed implementations employ a programmable network device, such as a switch, to inject events into traffic and mirror the traffic for subsequent analysis. The events can have user-specified event parameters to test different types of network stack behavior, such as how the network adapters respond to corrupted packets, dropped packets, or explicit congestion notifications.