Re: 3GPP RTP header extension
"Schwarz, Albrecht (Albrecht)" <[email protected]> Mon, 3 Jun 2013 08:10:10 +0000
| Newsgroups | gmane.ietf.megaco,gmane.ietf.mmusic |
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| Message-ID | <786615F3A85DF44AA2A76164A71FE1AC046CF5@FR711WXCHMBA03.zeu.alcatel-lucent.com> |
--===============7541199249713713137== Content-Language: en-US Content-Type: multipart/alternative; boundary="_000_786615F3A85DF44AA2A76164A71FE1AC046CF5FR711WXCHMBA03zeu_" --_000_786615F3A85DF44AA2A76164A71FE1AC046CF5FR711WXCHMBA03zeu_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable The subject was also on the agenda of 3GPP CT4 at last meeting. It may be noted that RFC 5285 is special with regards to the definition of = two capabilities of a) IP data path (RTP header extension; clause 4/RFC 5285) and b) IP signaling path (SDP signalling; ; clauses 5&6/RFC 5285) in a single RFC. Both capabilities could be also defined in separated RFCs. The tight coupling of both capabilities in a single RFC may be interpreted = in the following: the network should not forward RTP packets with extended = headers in case of missing SDP "a=3Dextmap:" signalling or/and failed SDP O= /A. E.g., an interim RTP translator (RTP transport translator or RTP media tran= slator) would block RTP packets with extension headers (dependent on above = SDP O/A ...). Conclusion: there seems to be some implicit semantics in RFC 5285 in my understanding. Regards, Albrecht From: [email protected] [mailto:[email protected]] On Behalf Of= Christer Holmberg Sent: Freitag, 24. Mai 2013 12:06 To: [email protected] Subject: [MMUSIC] 3GPP RTP header extension Hi, In the virtual interim meeting yesterday, I was requested to look into the = RTP header extension(s) defined by 3GPP. 3GPP SA4 has defined a header extension for "Coordination of Video Orientat= ion" purpose (may be of interest for CLUE btw, but that's a separate story)= . The length of the extension is 1 byte. For more information, see section 7.4.5 of 3GPP TS 24.114 :) http://www.3gpp.org/ftp/Specs/archive/26_series/26.114/26114-c10.zip Regards, Christer --_000_786615F3A85DF44AA2A76164A71FE1AC046CF5FR711WXCHMBA03zeu_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable <html xmlns:v=3D"urn:schemas-microsoft-com:vml" xmlns:o=3D"urn:schemas-micr= osoft-com:office:office" xmlns:w=3D"urn:schemas-microsoft-com:office:word" = xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" xmlns=3D"http:= //www.w3.org/TR/REC-html40"> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dus-ascii"= > <meta name=3D"Generator" content=3D"Microsoft Word 12 (filtered medium)"> <style><!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4;} @font-face {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4;} @font-face {font-family:Tahoma; panose-1:2 11 6 4 3 5 4 4 2 4;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0cm; margin-bottom:.0001pt; font-size:11.0pt; font-family:"Calibri","sans-serif";} a:link, span.MsoHyperlink {mso-style-priority:99; color:blue; text-decoration:underline;} a:visited, span.MsoHyperlinkFollowed {mso-style-priority:99; color:purple; text-decoration:underline;} span.EmailStyle17 {mso-style-type:personal; font-family:"Calibri","sans-serif"; color:windowtext;} span.EmailStyle18 {mso-style-type:personal-reply; font-family:"Courier New"; font-variant:normal !important; color:#1F497D; text-transform:none; text-shadow:none; font-weight:normal; font-style:normal; text-decoration:none none; vertical-align:baseline;} .MsoChpDefault {mso-style-type:export-only; font-size:10.0pt;} @page WordSection1 {size:612.0pt 792.0pt; margin:72.0pt 72.0pt 72.0pt 72.0pt;} div.WordSection1 {page:WordSection1;} --></style><!--[if gte mso 9]><xml> <o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" /> </xml><![endif]--><!--[if gte mso 9]><xml> <o:shapelayout v:ext=3D"edit"> <o:idmap v:ext=3D"edit" data=3D"1" /> </o:shapelayout></xml><![endif]--> </head> <body lang=3D"DE" link=3D"blue" vlink=3D"purple"> <div class=3D"WordSection1"> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">The subject was also on the a= genda of 3GPP CT4 at last meeting.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">It may be noted that RFC 5285= is special with regards to the definition of two capabilities of <o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">a) IP data path (RTP header e= xtension; clause 4/RFC 5285) and <o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">b) IP signaling path (SDP sig= nalling; ; clauses 5&6/RFC 5285)<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">in a single RFC. Both capabil= ities could be also defined in separated RFCs.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">The tight coupling of both ca= pabilities in a single RFC may be interpreted in the following: the network= should not forward RTP packets with extended headers in case of missing SDP “a=3Dextmap:” signalling or/and failed = SDP O/A.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">E.g., an interim RTP translat= or (RTP transport translator or RTP media translator) would block RTP packe= ts with extension headers (dependent on above SDP O/A …).<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">Conclusion:<o:p></o:p></span>= </p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">there seems to be some implic= it semantics in RFC 5285 in my understanding.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">Regards,<o:p></o:p></span></p= > <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D">Albrecht<o:p></o:p></span></p= > <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-= family:"Courier New";color:#1F497D"><o:p> </o:p></span></p> <div> <div style=3D"border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm = 0cm 0cm"> <p class=3D"MsoNormal"><b><span lang=3D"EN-US" style=3D"font-size:10.0pt;fo= nt-family:"Tahoma","sans-serif"">From:</span></b><span = lang=3D"EN-US" style=3D"font-size:10.0pt;font-family:"Tahoma",&qu= ot;sans-serif""> [email protected] [mailto:[email protected]= rg] <b>On Behalf Of </b>Christer Holmberg<br> <b>Sent:</b> Freitag, 24. Mai 2013 12:06<br> <b>To:</b> [email protected]<br> <b>Subject:</b> [MMUSIC] 3GPP RTP header extension<o:p></o:p></span></p> </div> </div> <p class=3D"MsoNormal"><o:p> </o:p></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">Hi,<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">In the virtual interim meeting = yesterday, I was requested to look into the RTP header extension(s) defined= by 3GPP.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">3GPP SA4 has defined a header e= xtension for “Coordination of Video Orientation” purpose (may b= e of interest for CLUE btw, but that’s a separate story). The length = of the extension is 1 byte.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">For more information, see secti= on 7.4.5 of 3GPP TS 24.114 :)<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"><a href=3D"http://www.3gpp.org/= ftp/Specs/archive/26_series/26.114/26114-c10.zip">http://www.3gpp.org/ftp/S= pecs/archive/26_series/26.114/26114-c10.zip</a><o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">Regards,<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">Christer<o:p></o:p></span></p> </div> </body> </html> --_000_786615F3A85DF44AA2A76164A71FE1AC046CF5FR711WXCHMBA03zeu_-- --===============7541199249713713137== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Megaco mailing list [email protected] https://www.ietf.org/mailman/listinfo/megaco --===============7541199249713713137==--