Correlating Media and Signaling Streams via Composite Keys
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Solution Overview
Problem
The correlation of signaling plane and media plane in VoIP services is challenging due to limited information availability, time constraints caused by port reuse, geographic distribution, and Network Address Translation (NAT), leading to false positives and complexity in passive mid-point monitoring scenarios.
Innovation Solution
A method using correlation keys generated by signaling plane and media plane probes to correlate media streams and signaling sessions based on data records, with hash keys associated with media data paths and timestamps, allowing for accurate identification of media streams and signaling sessions across multiple hosts and geographically distributed components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If address tuple (IP address and port) is used to identify media streams, then correlation between signaling plane and media plane can be established, but port reuse causes false positives and reduces correlation accuracy
Solution Approach 1:
The patent extends the correlation identifier from a single address tuple to a composite key spanning multiple dimensions: address tuple, timestamp, and service identifier. This multi-dimensional approach distinguishes between different media streams that may reuse the same address tuple at different times or for different services, thereby eliminating false positives while maintaining accurate correlation.
Solution Approach 2:
The patent performs preliminary binding of media streams to signaling sessions using a composite correlation key before port reuse can cause confusion. By establishing the correlation relationship in advance with multiple identifying parameters, the system prevents false positives that would occur if only address tuple was used, especially in scenarios where ports are reused after service termination.
2Productivity
If multiple media streams are monitored in passive mid-point monitoring, then comprehensive service analysis is achieved, but correlation complexity increases due to multiple address tuples
Solution Approach 1:
The patent creates a universal correlation key structure that can identify and correlate multiple media streams across different services using a consistent binding mechanism. The composite key (address tuple + timestamp + service identifier) serves as a universal identifier that works for single-stream and multi-stream scenarios alike, simplifying the correlation mechanism while enabling comprehensive service analysis.
Solution Approach 2:
The patent introduces a service identifier as an intermediary element that links multiple media streams to their corresponding signaling sessions. This intermediary binding relationship simplifies the correlation process by providing a clear mapping between media plane traffic and signaling plane sessions, reducing the complexity of handling multiple address tuples in passive monitoring scenarios.
3Adaptability or versatility
If address tuple is reused after service termination, then port resources are efficiently utilized, but correlation accuracy decreases due to inability to distinguish between different services
Solution Approach 1:
The patent adds timestamp and service identifier dimensions to the address tuple to create a composite correlation key. This multi-dimensional approach allows the system to distinguish between media streams using the same address tuple at different times or for different services, maintaining high identification accuracy while fully supporting port reuse for resource efficiency.
Solution Approach 2:
The patent performs preliminary binding of media streams to signaling sessions using the composite correlation key before address tuple reuse occurs. By establishing the correlation relationship in advance with multiple identifying parameters, the system ensures accurate stream identification even when the same address tuple is later reused for different services, thus maintaining measurement precision while enabling port reuse.
Data Source
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AI summary
This invention relates to methods for correlating media streams and signaling sessions of services, for example, in a passive monitoring system of a packet-switched network. Furthermore, the invention also relates to an implementation of these methods in hardware and software, and provides a signaling plane probe, a media plane probe and a correlation unit. Moreover, a passive monitoring system comprising one or more of these hardware devices is provided. To correlate media streams and signaling sessions of services, the invention proposes to independently generate correlation keys in a media plane probe for monitored media streams and correlation keys for signaling sessions that are monitored by a signaling plane probe in a fashion that matching correlation keys are generated for a respective service. By identifying reports on the media streams and reports on the signaling session that contain matching correlation keys respectively, the media streams and the signaling streams are correlated in a correlation unit.