Signaling Session Identifier for VoIP Media Correlation

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Solution Overview

Problem

The correlation of signaling and media planes in VoIP services within packet-switched networks is challenging due to limited information availability, time constraints from port reuse, geographic distribution, and Network Address Translation (NAT), which leads to false positives and complexity in identifying media streams and signaling sessions.

Innovation Solution

A correlation mechanism using a signaling session identifier is introduced, where a signaling plane probe detects signaling sessions and media data paths, generating a hash value as the identifier, and registers them with a correlation unit, allowing a media plane probe to query for corresponding identifiers to establish correlations between media paths and signaling sessions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If address tuple (IP address and port) is used to correlate media plane and signaling plane, then correlation can be established, but false positives occur due to port reuse and limited information availability

Engineering Contradiction:
Improvecorrelation accuracyVSAvoidfalse positive rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The correlation key is segmented into multiple components: signaling protocol identifier, message type identifier, session identifier, and address tuple. This segmentation allows for more precise matching by requiring all components to align, thereby reducing false positives while maintaining correlation accuracy.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If multiple media streams are supported for two-way communication, then service functionality is improved, but correlation complexity increases due to multiple address tuples

Engineering Contradiction:
Improvemedia stream supportVSAvoidcorrelation mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The correlation mechanism uses a universal correlation key structure that can identify multiple media streams through different message type identifiers within the same signaling session. This allows the system to handle multiple streams without increasing overall mechanism complexity, as the same correlation key components serve multiple identification purposes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Quantity of substance

If port range is limited by transport layer protocol, then resource usage is optimized, but unique identification of media streams becomes difficult due to port reuse

Engineering Contradiction:
Improveport rangeVSAvoidstream identification accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The system adds another dimension to identification by incorporating signaling protocol identifiers and message type identifiers beyond just the address tuple. This dimensional expansion allows for unique stream identification even when address tuples are reused, overcoming the limitations of limited port ranges.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2466799B1Correlation of media plane and signaling plane of media services in a packet-switched network
Publication Date: 2014.04.23 VOIPFUTURE
  • EP2466799B1 patent drawingFigure 1
  • EP2466799B1 patent drawingFigure 2~3
  • EP2466799B1 patent drawingFigure 4

AI summary

This invention relates to methods for correlating at least one media path and a signaling session of a packet-switched network and to an implementation of these methods in hardware and software. To overcoming one or more of the limitations and challenges on the correlation of signaling plane and media plane of services, the invention defines a key, which can be used for correlation of media streams and signaling sessions. The invention is based on a signaling probe identifying new services and associated media paths of the media plane by detecting their corresponding signaling sessions and determining for each service a signaling session identifier. The signaling probe registers the signaling sessions and their media paths at a correlation unit using the signaling session identifiers as a key, which allows a media probe to query the correlation unit for respective signaling session identifiers that correspond to media paths detected in the media plane traffic.