Asymmetrical Routing Anomaly Detection via Distributed Traffic Feature Merging

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Solution Overview

Problem

Existing anomaly detection systems in computer networks face challenges in distinguishing between legitimate and malicious traffic flows, particularly in the presence of asymmetrical routing, which complicates the identification of Denial of Service (DoS) attacks and makes it difficult to model normal network behavior due to the directional nature of Internet traffic.

Innovation Solution

A distributed learning architecture that identifies asymmetrical routing by discovering missing traffic flows, electing a primary device to receive and process traffic characteristics from peer devices, and using machine learning-based anomaly detection to merge features from both directions of traffic flows for accurate modeling and anomaly detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traffic flow characteristics are monitored at a single device in asymmetric routing, then device complexity is reduced, but measurement precision of complete traffic behavior deteriorates

Engineering Contradiction:
Improveanomaly detection system complexityVSAvoidtraffic flow characterization accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system divides the network into multiple monitoring segments, with each device independently monitoring local traffic flows. Each device captures traffic characteristics for flows passing through it, and these segmented measurements are later aggregated to form a complete picture of asymmetric traffic patterns without requiring one device to handle all monitoring complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system merges traffic flow characteristics from multiple devices by matching flows based on endpoint pairs. Device 1's observation of forward traffic and Device 2's observation of return traffic are combined to create a complete bidirectional flow profile, enabling precise measurement of asymmetric routing patterns while distributing monitoring complexity across multiple devices.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If traffic characteristics are collected from multiple devices, then anomaly detection accuracy is improved, but data transmission overhead increases

Engineering Contradiction:
Improveanomaly detection accuracyVSAvoiddata transmission overhead
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The system extracts only the essential traffic characteristics needed for anomaly detection from each device's complete traffic data. By selecting and transmitting only relevant flow features (such as endpoint pairs, protocol types, and traffic volumes) rather than complete packet captures, the system achieves accurate anomaly detection while minimizing data transmission overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Each device performs preliminary processing of traffic flows locally by identifying and characterizing flows before transmission. Devices pre-process traffic data to extract meaningful features and filter out redundant information, reducing the volume of data that needs to be transmitted to the central anomaly detection system while maintaining detection accuracy.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If complete bidirectional traffic flows are monitored, then reliability of anomaly detection is improved, but device complexity increases due to need to track both directions

Engineering Contradiction:
Improveanomaly detection reliabilityVSAvoidtraffic flow tracking complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system segments the bidirectional traffic monitoring task across multiple devices based on their positional roles in the asymmetric routing path. Device 1 monitors forward traffic while Device 2 monitors return traffic, with each device handling only one direction. This segmentation reduces individual device complexity while maintaining reliable detection through coordinated observation of both directions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system introduces a central coordinator that receives traffic flow characteristics from multiple devices and performs the matching and merging operations. This intermediary consolidates the complexity of tracking bidirectional flows at a centralized location, allowing individual monitoring devices to remain simple while still achieving reliable anomaly detection through their coordinated observations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS10009364B2Gathering flow characteristics for anomaly detection systems in presence of asymmetrical routing
Publication Date: 2018.06.26 CISCO TECHNOLOGY INC
  • US10009364B2 patent drawing
  • US10009364B2 patent drawing
  • US10009364B2 patent drawing

AI summary

In one embodiment, a first device in a network identifies a first traffic flow between two endpoints that traverses the first device in a first direction. The first device receives information from a second device in the network regarding a second traffic flow between the two endpoints that traverses the second device in a second direction that is opposite that of the first direction. The first device merges characteristics of the first traffic flow captured by the first device with characteristics of the second traffic flow captured by the second device and included in the information received from the second device, to form an input feature set. The first device detects an anomaly in the network by analyzing the input feature set using a machine learning-based anomaly detector.