Signaling Session Identifier Correlation for VoIP Media Streams
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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 correlation information, port reuse, geographic distribution, and Network Address Translation (NAT), leading to false positives and increased complexity in identifying and matching media streams with signaling sessions.
Innovation Solution
A correlation mechanism using a signaling session identifier is introduced, where a signaling plane probe detects signaling sessions and associated media data paths, registering them at a correlation unit, allowing a media plane probe to query for corresponding identifiers and establish correlations between media paths and signaling sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If correlation is based solely on address tuples (IP address and port), then the correlation mechanism is simple, but it leads to false positives due to port reuse and insufficient differentiation between multiple media streams
Solution Approach 1:
The patent introduces a new dimension to correlation by using RTP session identifiers (SSRC) in addition to address tuples. This moves from two-dimensional correlation (IP+port) to three-dimensional correlation (IP+port+SSRC), enabling precise identification of individual media streams even when address tuples are reused across different sessions or services.
Solution Approach 2:
The patent introduces an intermediary correlation mechanism that mediates between the signaling plane and media plane. The correlation unit acts as an intermediary that receives both signaling information and media stream information, processes them together, and generates accurate correlations, thereby resolving the false positive issue without requiring complex changes to either plane.
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 and potential false positives
Solution Approach 1:
The patent segments the correlation process into distinct components: a signaling plane probe that extracts signaling information, a media plane probe that extracts media stream information, and a correlation unit that combines them. This segmentation allows each component to handle specific tasks independently, managing the complexity of multiple media streams through modular processing rather than monolithic correlation.
Solution Approach 2:
The patent performs preliminary actions by having the signaling plane probe extract and prepare signaling information (including address tuples) before the actual media stream correlation occurs. This pre-processing of signaling data allows the correlation unit to efficiently match media streams to the correct signaling sessions without complex real-time analysis, reducing overall system complexity.
3Productivity
If geographic distribution of network elements is implemented, then network scalability and performance are improved, but correlation difficulty increases due to dispersed monitoring locations
Solution Approach 1:
The patent implements a universal correlation mechanism that can operate across multiple geographic locations. The correlation unit is designed to receive signaling and media information from dispersed network elements and perform unified correlation, making the system scalable to geographic distribution without increasing per-location complexity. Each location uses the same standardized correlation process regardless of its position in the network.
Data Source
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.