Modified P-Early-Media Header Selective Media Stream Authorization
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Solution Overview
Problem
Current SIP signalling technologies are inadequate in defining and managing media streams during the pre-call setup phase in multimedia sessions, leading to unnecessary network load due to the inability to selectively authorize specific media streams and their directions.
Innovation Solution
A modified P-Early-Media (PEM) header is introduced to specify the media types and directions authorized during the pre-call setup phase, allowing for the selection of specific media streams within a set of streams, independent of their order in the SDP description field, and including identification parameters for precise stream management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the PEM header applies to all media streams of a given type, then the control mechanism is simple and universal, but it cannot selectively authorize specific streams leading to unnecessary network load
Solution Approach 1:
The patent segments the media stream authorization mechanism by introducing a specific identifier field in the PEM header that can reference individual media streams within an SDP description. This allows the header to apply to specific streams rather than all streams of a type, enabling selective authorization while maintaining the existing PEM header structure. The identifier acts as a pointer to particular stream descriptions in the SDP body, achieving fine-grained control without complete structural overhaul.
Solution Approach 2:
The patent applies local quality by allowing different PEM header instances to target different media streams with specific identifiers. Each PEM header can be customized to authorize or restrict particular streams based on their identifier, creating localized control rules rather than blanket authorization for all streams of a media type. This enables precise control over which specific audio, video, or data streams are authorized during pre-call setup.
2Productivity
If all media streams are authorized during pre-call setup, then the setup process is simple and fast, but unnecessary streams consume network resources
Solution Approach 1:
The patent implements preliminary action by authorizing only the specific media streams identified in the PEM header during the pre-call setup phase, rather than all possible streams. The identifier in the PEM header pre-specifies which streams are permitted, so the network and terminals can immediately begin transmitting only those authorized streams without subsequent negotiation or restriction. This prevents unnecessary network resource consumption from the outset while maintaining fast setup.
Solution Approach 2:
The patent extracts the authorization restriction from a blanket policy and applies it selectively to specific media streams through the identifier mechanism. Instead of taking out the restriction entirely (which would authorize all streams), it extracts and applies restrictions only to streams not identified in the PEM header, or conversely, selectively authorizes only the identified streams. This separates the authorized streams from the unauthorized ones, preventing waste of network resources.
3Reliability
If the PEM header controls all media streams uniformly, then the control mechanism is simple, but it cannot prevent incompatible codec transmission
Solution Approach 1:
The patent segments the media stream control by introducing identifiers that can uniquely reference specific stream descriptions in the SDP body. Each identified stream can be associated with specific codec parameters, allowing the network to authorize only streams with compatible codecs. The identifier mechanism enables granular control over each stream's authorization status based on its codec characteristics, preventing incompatible codec transmission while maintaining manageable complexity through reuse of existing SDP identifier conventions.
Data Source
AI summary
The disclosed technology relates to a method for managing a multimedia session between a calling terminal and at least one called terminal. In one aspect, the multimedia session comprises a pre-call setup phase and a call phase. According to the disclosed technology, the method comprises, during the pre-call setup phase, a reception of an INVITE message generated by a calling terminal. The INVITE message comprises a description field describing the multimedia session and containing information relating to a set of media streams. A response is generated to the INVITE message, wherein the response comprises a header containing at least one media type and at least one first call parameter applicable to at least one media stream of the media type, among the set of media streams.