Intermediary Device Identifying Dynamic Codec Media Flows
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Solution Overview
Problem
Network diagnostic tools struggle to determine codecs used in RTP sessions with dynamically mapped payload identifiers, as they cannot interpret payload data or predict traffic behaviors and bandwidth requirements by passively monitoring RTP packets.
Innovation Solution
An intermediary networking device intercepts network flow information, requests endpoint characteristics, and searches a profile database to map payload identification numbers to encoding types, enabling the determination of encoding types for content transferred over the network flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dynamic payload identifiers (96-127) are used to support new codecs without revising RTP standard, then adaptability to new codecs is improved, but ability of intermediary devices to determine codecs is worsened
Solution Approach 1:
The patent introduces an intermediary device (network monitor/diagnostic tool) that actively participates in the profile negotiation process between endpoints. This intermediary requests and receives profile information that maps dynamic payload identifiers to specific codecs, enabling it to translate between the dynamic identifiers and meaningful codec information for monitoring and diagnostic purposes.
Solution Approach 2:
The patent performs profile negotiation and codec mapping before actual media transmission begins. The intermediary device establishes the mapping between dynamic payload identifiers and codecs in advance through SDP exchange, so that when packets arrive during the session, the intermediary can immediately interpret them without needing to participate in real-time negotiation.
2Adaptability or versatility
If endpoints negotiate custom profiles privately without intermediary participation, then flexibility in codec selection is improved, but visibility for network diagnostic tools is worsened
Solution Approach 1:
The intermediary device positions itself in the signal path between endpoints and actively requests profile information from one or both endpoints. The endpoints provide their negotiated profile mappings to the intermediary, which then uses this information to interpret traffic. This maintains endpoint privacy while providing necessary visibility to the intermediary for monitoring and diagnostics.
Solution Approach 2:
The intermediary sends requests to endpoints for profile information and receives responses containing the mapping data. This feedback mechanism allows the intermediary to obtain the necessary codec identification information without disrupting the private negotiation process between endpoints, enabling the intermediary to translate dynamic payload identifiers into meaningful codec information.
Data Source
AI summary
Techniques for identifying media network flows that use dynamic codec identifications are described. In an embodiment, network flow information for a network flow between a first endpoint and a second endpoint is received from a network device interposed between the first endpoint and the second endpoint, wherein the network flow information includes at least an address for the first endpoint and a particular payload identification number. A request is sent to the first endpoint for one or more characteristics belonging to the first endpoint. In response to receiving the one or more characteristics, a profile database is searched for an entry that maps the one or more characteristics to a profile, wherein the profile maps one or more payload identification numbers to one or more encoding types. An encoding type for content transferred over the network flow is determined based on the profile and the particular payload identification number.