Location-Independent Network Delay Measurement via TCP Window Tracking

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Solution Overview

Problem

Existing network delay measurement techniques are location-dependent, making them unsuitable for virtualization and cloud solutions, where scalability and consistent delay determination are essential.

Innovation Solution

A network monitoring device determines location-independent network delays by tracking TCP window changes, advertised window updates, and congestion window dynamics, allowing for consistent measurement across client-side, server-side, and intermediate locations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional end-user response time measurement techniques are used, then location-dependent delay data can be obtained, but the measurements do not scale appropriately for virtualization and cloud solutions

Engineering Contradiction:

Improvescalability for virtualization and cloud solutionsVSAvoidlocation independence of delay measurements

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary measurement approach that observes TCP window updates and congestion control signals as mediators between sender and receiver. Instead of measuring from specific endpoint locations, the system uses these intermediary protocol signals to infer delay characteristics that are independent of measurement location, enabling scalability across virtualized and cloud environments.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the measurement parameters from traditional end-to-end response time to TCP-specific parameters including window update intervals, congestion window changes, and slow start dynamics. These parameter changes enable location-independent measurements that scale appropriately for virtualization and cloud solutions while maintaining measurement precision.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If end-user response time is measured from different locations (close to server, close to client, or in between), then location-specific delay data is obtained, but consistent delay determination across locations is not achieved

Engineering Contradiction:

Improveconsistent delay determinationVSAvoidlocation independence

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent creates a universal measurement methodology that functions independently of measurement location. By using TCP protocol signals (window updates, congestion control mechanisms) that are generated and processed at multiple points in the network, the system achieves location-independent delay determination that works consistently whether measured near the server, near the client, or at intermediate points.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent utilizes feedback mechanisms inherent in TCP congestion control and window management. By monitoring how senders adjust their transmission windows based on receiver feedback and network conditions, the system derives delay characteristics that are consistent across different measurement locations, as these feedback signals reflect the actual network state rather than location-specific artifacts.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11153220B2Methods and apparatus to determine network delay with location independence

Publication Date: 2021.10.19 NETSCOUT SYSTEMS INC

AI summary

The techniques disclosed herein determine a location independent network delay via a network monitoring device. Such techniques particularly include determining various delays such as a zero window delay, an advertised window delay, and a congestion window delay (including slow start delays).