No-Op RTP Packets for Media Path Analysis
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Solution Overview
Problem
Current IP networks lack a mechanism to assess media channel viability without playing out media, which is undesirable in scenarios like session setup, synthetic load testing, and traffic analysis, and existing solutions require non-standard behavior or separate test paths.
Innovation Solution
The use of no-op media payload packets in RTP, which contain no media content and set a marker bit to trigger RTCP reports, allowing for media path analysis without actual media playback, utilizing existing RTP and RTCP protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If test packets are sent through an independent test path, then media path verification can be performed, but the test path and media path may take different routes over the IP network, resulting in inaccurate media path assessment
Solution Approach 1:
The patent merges the test packet transmission with the actual media path by using the same RTP stream for both purposes. Instead of creating a separate test path, the invention uses the media path itself to carry test packets (no-op packets), ensuring that the verification is performed on the exact path that will be used for actual media transmission.
Solution Approach 2:
The RTP stream serves multiple functions: it carries both test packets for path verification and actual media content. The no-op packets are indistinguishable from regular media packets in terms of routing, allowing the same infrastructure to handle both testing and media transmission without requiring separate dedicated test infrastructure.
2Loss of time
If test packets are sent before establishing the call, then media path can be verified early, but this requires awkward associations of RTP streams and non-standard behavior of endpoints
Solution Approach 1:
The patent performs media path verification as a preliminary action during the call setup phase, before actual media transmission begins. The no-op packets are sent and processed during signaling establishment, allowing the media path to be verified early in the call setup process without delaying the overall call establishment.
Solution Approach 2:
The endpoint uses its own existing RTP and RTCP processing capabilities to handle the no-op packets. The receiver processes no-op packets using the same mechanisms it would use for regular media packets, and generates RTCP reports automatically without requiring special external testing equipment or complex coordinated actions between multiple endpoints.
3Measurement precision
If actual media is played out during testing, then complete media path functionality can be assessed, but it is undesirable when session setup assessment is needed before committing to full media session
Solution Approach 1:
The patent extracts the testing function from actual media content by using no-op packets that contain no media payload. These packets carry only the necessary RTP headers for path verification purposes, separating the testing function from media content transmission and allowing verification without wasting actual media data.
Solution Approach 2:
The invention changes the parameter of packet content from actual media data to no-op placeholder data. By modifying the payload type indicator in the RTP header to signify a no-op packet, the system maintains the same packet structure and routing behavior while changing the content parameter to enable verification without media playback.
Data Source
AI summary
No-op media payload packets are used to analyze a media path in a packet switched network. In one embodiment, the no-op packets are Real Time Protocol (RTP) payload packets that contain no media content. A Real Time Control Protocol (RTCP) report is generated for the received RTP no-op packets. A marker bit is set in one of the no-op packets that triggers the no-op packet receiver to send back the RTCP report. The media steam is transmitted when the statistics in the RTCP report indicate a viable media path.