RFC 3890 on A Transport Independent Bandwidth Modifier for the Session Description Protocol (SDP)

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        RFC 3890

        Title:      A Transport Independent Bandwidth Modifier
                    for the Session Description Protocol (SDP)
        Author(s):  M. Westerlund
        Status:     Standards Track
        Date:       September 2004
        Mailbox:    Magnus.Westerlund@ericsson.com
        Pages:      22
        Characters: 49894
        Updates/Obsoletes/SeeAlso:    None

        I-D Tag:    draft-ietf-mmusic-sdp-bwparam-06.txt

        URL:        ftp://ftp.rfc-editor.org/in-notes/rfc3890.txt

This document defines a Session Description Protocol (SDP) Transport
Independent Application Specific Maximum (TIAS) bandwidth modifier
that does not include transport overhead; instead an additional packet
rate attribute is defined.  The transport independent bit-rate value
together with the maximum packet rate can then be used to calculate
the real bit-rate over the transport actually used.

The existing SDP bandwidth modifiers and their values include the
bandwidth needed for the transport and IP layers.  When using SDP with
protocols like the Session Announcement Protocol (SAP), the Session
Initiation Protocol (SIP), and the Real-Time Streaming Protocol
(RTSP), and when the involved hosts has different transport overhead,
for example due to different IP versions, the interpretation of what
lower layer bandwidths are included is not clear.

This document is a product of the Multiparty Multimedia Session
Control Working Group of the IETF.

This is now a Proposed Standard Protocol.

This document specifies an Internet standards track protocol for
the Internet community, and requests discussion and suggestions
for improvements.  Please refer to the current edition of the
"Internet Official Protocol Standards" (STD 1) for the
standardization state and status of this protocol.  Distribution
of this memo is unlimited.

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Joyce K. Reynolds and Sandy Ginoza
USC/Information Sciences Institute

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