Human Language Modality Grouping Semantics in Session Description Protocol

Document Type Expired Internet-Draft (individual)
Author Gunnar Hellstrom 
Last updated 2018-07-16 (latest revision 2018-01-03)
Replaces draft-hellstrom-language-grouping
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When setting up a real-time communication session, there may be a need to indicate preference for which media and modality (spoken, written or signed) to use for language communications or a need to indicate preference for receiving the same language content simultaneously in two modalities. This document defines the semantics for grouping media for such purposes in the Session Description Protocol (SDP). The semantics defined in this document are based on the SDP Grouping Framework. Applications are for example negotiation the most suitable common modality or modalities for language communications in a real-time session. The indications are specified for the sending and receiving direction separately.


Gunnar Hellstrom (

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