Telecom Interconnect Bypass Detection via Real Subscriber Test Calls

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Solution Overview

Problem

Existing methods for detecting interconnect bypass in telecommunication networks face challenges such as high latency, susceptibility to counter-detection, and the need for complex hardware installations, which hinder effective identification and prevention of bypass activities.

Innovation Solution

A method and system that utilize test calls to real subscriber numbers, analyzing received calling line identifiers and time information to detect bypass activity without requiring additional hardware in the signaling path, using intelligent selection of real subscriber numbers and leveraging Call Data Records for accurate CLI analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If test calls are made to detect interconnect bypass, then detection capability is improved, but the risk of counter-detection by bypass operators increases

Engineering Contradiction:

Improvebypass detection capabilityVSAvoidsusceptibility to counter-detection

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system dynamically selects different real subscriber numbers for test calls based on predefined selection criteria, making the test call pattern unpredictable to bypass operators. This dynamic adaptation prevents bypass operators from identifying and blocking test calls, thereby maintaining detection effectiveness while reducing counter-detection risk

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes key parameters of test calls including the called number (selected from real subscribers), timing, and frequency. By varying these parameters according to selection criteria, the system makes test calls indistinguishable from normal traffic patterns, preventing bypass operators from detecting and countering the detection mechanism

Inventive Principle:

Principle #35Parameter changes

2Reliability

If traditional interconnection facilities are used, then call routing reliability is improved, but interconnection charges increase

Engineering Contradiction:

Improvecall routing reliabilityVSAvoidinterconnection charges

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system converts the harmful effect of interconnect bypass (revenue loss) into a beneficial detection mechanism. By monitoring CLI replacements and analyzing call patterns that indicate bypass activity, the system identifies and enables blocking of bypass operations, thereby protecting revenue while maintaining reliable interconnection for legitimate calls

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If end user facilities are used for bypass, then bypass operation is enabled, but quality of service deteriorates

Engineering Contradiction:

Improvebypass capabilityVSAvoidquality of service

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system replaces physical monitoring of call quality with electronic analysis of signaling data. By examining CLI fields in signaling messages and comparing them against expected values, the system detects bypass activity without interfering with the actual call flow, thereby maintaining service quality while enabling detection and prevention of bypass operations

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If CLI replacement is used in bypass, then bypass effectiveness is improved, but detection accuracy worsens

Engineering Contradiction:

Improvebypass effectivenessVSAvoiddetection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system implements feedback by continuously monitoring CLI information in signaling messages and comparing it against expected values. When CLI replacement is detected (mismatch between expected and actual CLI), the system generates alerts and enables blocking actions. This feedback mechanism maintains high detection accuracy despite bypass operators using CLI replacement techniques

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3657769B1Method and system for detection of interconnect bypass using test calls to real subscribers

Publication Date: 2022.08.31 SIGOS BVBA

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AI summary

A method for detection of a bypass (134; 734; 834) of an interconnect (133; 733; 833) to a telecommunication network (130; 730; 830), comprises: - generating a test call (263; 367; 467; 567; 663) to or through a real subscriber number of a real subscriber (131; 231; 331; 431; 531; 631; 731; 831) active in the telecommunication network; - obtaining call data (154, 153; 265; 372; 472; 572; 665; 753; 853) from the operator of the real subscriber (131; 231; 331; 431; 531; 631; 731) or from a test probe (132; 232; 332; 432; 532; 632; 732; 832) whereto the real subscriber number of the real subscriber (131; 231; 331; 431; 531; 631; 731; 831) is temporarily forwarded during a time interval wherein the test call (263; 367; 467; 567; 663) is made; - extracting a received calling line identifier for the test call (263; 367; 467; 567; 663) from the call data (154, 153; 265; 372; 472; 572; 665; 753; 853); and - detecting presence of a bypass (134; 734; 834) by analysis of the received calling line identifier.