SDP attribute for qualifying Media Formats with Generic Parameters

Document Type Expired Internet-Draft (individual in tsv area)
Last updated 2015-10-14 (latest revision 2003-05-20)
Stream IETF
Intended RFC status Proposed Standard
Expired & archived
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IESG IESG state Expired (IESG: Dead)
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This document defines a new SDP attribute called general-purpose media descriptor (gpmd). The gpmd attribute allows the use of new informative parameters, gpmd parameters, to qualify existing media formats. These gpmd parameters are not part of the standard (e.g., MIME) definition of the media format and support for them with a given media format can not be assumed. Their use is therefore limited to cases where they provide information that may be of use to the other party in a session but is not critical to the use of the particular media format. This document also defines a specific gpmd parameter, voice-band data, which can be used to describe a media format as carrying voice-band data. This enables the receiver to optimize its handling of the media received.


Rajesh Kumar (
Flemming Andreasen (

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