Software Packet Simulator for Network Impairment Testing

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Solution Overview

Problem

Standard network impairment test equipment is costly, making it difficult for equipment vendors to reproduce and evaluate packet loss and jitter conditions in a lab to determine and counteract degraded service issues in cable TV networks.

Innovation Solution

A software-based simulator that intercepts packets and applies delay or drops them to simulate network impairments, using a queue system with a delay variable to manage packet flow and simulate various impairment conditions such as packet loss and jitter, allowing for cost-effective testing of media terminal adaptors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If standard network impairment test equipment is used to simulate packet loss and jitter, then measurement precision and reliability are improved, but device cost increases significantly

Engineering Contradiction:

Improvepacket loss and jitter simulation accuracyVSAvoidequipment cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent creates a software-based copy of network impairment test equipment functionality. Instead of using expensive physical test equipment, the invention implements a simulator that replicates packet loss and jitter conditions through software algorithms running on standard computing hardware, thereby achieving the same measurement and simulation capabilities at minimal cost.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical test equipment system with a software-based simulation system. The simulator uses software algorithms to generate packet delays, drops, and jitter conditions that previously required specialized physical network impairment equipment, substituting computational processes for hardware-based test systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If standard network impairment test equipment is purchased, then simulation reliability is improved, but productivity decreases due to high equipment cost and acquisition time

Engineering Contradiction:

Improveservice degradation evaluation reliabilityVSAvoidtesting efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements a self-service testing approach where the simulator is freely available as software that vendors can deploy themselves without needing to purchase or rent expensive external test equipment. The system enables organizations to perform their own network impairment simulations and service degradation evaluations using their existing infrastructure, eliminating dependency on costly external tools.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces expensive, long-term equipment investments with a low-cost software solution that can be deployed quickly and modified as needed. The simulator runs on standard hardware that is already present in most testing environments, eliminating the need for specialized equipment purchases and reducing both upfront costs and acquisition time.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Device complexity

If a software-based packet simulator is used, then device complexity is reduced and cost is lowered, but measurement precision may worsen compared to standard equipment

Engineering Contradiction:

Improvesimulation system complexityVSAvoidimpairment simulation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements configurable simulation parameters that allow precise control over packet delay values, drop patterns, and jitter characteristics. The software simulator uses adjustable parameters such as delay amounts, queue sizes, and randomization factors to accurately reproduce specific network impairment conditions, enabling precise measurement and simulation without complex hardware.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent incorporates feedback mechanisms where the simulator monitors packet flow characteristics and adjusts delay and drop patterns based on observed network conditions. The system tracks packet timing, queue depths, and transmission patterns to dynamically modify simulation parameters, ensuring accurate reproduction of real-world network impairments while maintaining software-based simplicity.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7751449B2Method and system for simulation multimedia packet loss and jitter

Publication Date: 2010.07.06 ARRIS ENTERPRISES LLC

AI summary

A Packet Loss and Jitter Simulator processes RTP packets coming through the MTA. Based on user input commands, the simulator drops or delays insertion of packets into the DSP portion of the MTA. Various modes that may be programmed include, but are not limited to, manual packet loss, fixed packet loss, random packet loss, manual jitter, fixed jitter, shift jitter, burst jitter, random jitter, and rolling jitter. All of these modes can be modified to simulate many real world conditions. The simulator typically operates on downstream packets, but can be used to provide similar functionality in the upstream direction.