Inline Traffic Impairment Testing for Distributed System Resilience

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Solution Overview

Problem

Existing testing methods for distributed systems are inefficient in simulating unpredictable real-world conditions and interactions between system components, leading to challenges in identifying weaknesses before they manifest as system-wide aberrant behaviors.

Innovation Solution

A test system is configured to generate impairment rules based on baseline traffic metrics, impair live traffic, and monitor how the system under test handles these impairments, using header modifications and attribute value pairs to facilitate efficient analysis of response traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If predefined tests are used to test distributed systems, then testing coverage is limited and predictable, but the ability to identify weaknesses under real-world conditions deteriorates

Engineering Contradiction:
Improvetesting reliabilityVSAvoidtest adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system uses live traffic from the production environment itself as the test subject, allowing the system to test itself under real conditions. The impairment rules engine dynamically generates test scenarios based on actual traffic patterns, making the testing system self-adaptive and self-serve without requiring external predefined test cases.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system dynamically changes traffic parameters such as latency, packet loss, and throughput by applying impairment rules to live traffic. These parameter modifications are applied in real-time based on detected weaknesses, enabling the system to adapt test conditions to match actual production scenarios rather than using static predefined tests.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If live traffic is impaired to simulate real-world conditions, then testing of real-world conditions improves, but traffic disruption and system impact worsen

Engineering Contradiction:
Improvesystem resilienceVSAvoidtraffic disruption
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system applies impairment rules selectively to specific traffic flows or parameters rather than disrupting all traffic. By targeting only the necessary portions of traffic to expose specific weaknesses, the system achieves testing objectives while minimizing overall traffic disruption and system impact.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system continuously monitors system responses to impaired traffic and uses this feedback to dynamically adjust impairment rules. When weaknesses are identified, the system modifies subsequent impairment applications to focus on areas needing improvement, reducing unnecessary traffic disruption while maintaining effective testing.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If impairment rules are applied to live traffic, then identification of performance issues improves, but testing complexity and system configuration requirements worsen

Engineering Contradiction:
Improveperformance measurement precisionVSAvoidtesting system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system introduces an intermediary impairment rules engine that sits between the live traffic and the analysis system. This intermediary component automatically generates, applies, and manages impairment rules based on detected weaknesses, shielding the complexity of performance measurement from the overall system configuration and reducing operational burden.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3739814B1Indirect testing using impairment rules
Publication Date: 2026.04.29 KEYSIGHT TECHNOLOGIES INC
  • EP3739814B1 patent drawingFigure 1
  • EP3739814B1 patent drawingFigure 2
  • EP3739814B1 patent drawingFigure 3

AI summary

According to one method, the method occurs at a first test device located inline between at least one traffic source and a network and/or system under test (NSUT), wherein the first test device is implemented using at least one processor and at least one memory. The method includes receiving, from a test controller, impairment rules generated from baseline metrics based on monitored live traffic for effecting traffic impairments; receiving traffic destined to the NSUT; impairing the traffic destined to the NSUT based on the impairment rules; sending the impaired traffic towards the NSUT, wherein the NSUT processes the impaired traffic; and sending, from the test device or a related tap, response information from the NSUT to the test controller for analyzing NSUT performance.