Re: H.248-controlled T.38 configurations: SDP- vs Property-based H.248 signalling
"Schwarz, Albrecht (Albrecht)" <[email protected]> Fri, 3 Aug 2012 10:25:11 +0200
| Newsgroups | gmane.ietf.megaco |
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| Message-ID | <5F7BCCF5541B7444830A2288ABBEBC96218B57EDB5@FRMRSSXCHMBSD2.dc-m.alcatel-lucent.com> |
--===============8511541477297440520== Content-Language: en-US Content-Type: multipart/alternative; boundary="_000_5F7BCCF5541B7444830A2288ABBEBC96218B57EDB5FRMRSSXCHMBSD_" --_000_5F7BCCF5541B7444830A2288ABBEBC96218B57EDB5FRMRSSXCHMBSD_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Thomas, looks like that we are now on the same page, i.e. if the T.38 endpoint (her= e IM-MGW) would support that capability, then it could be also used in the = negotiation of T.38 configurations with the remote T.38 endpoint. Hence, the T.38 parameters are not related to remote G3FEs. There would be then following changes in your CRs, let's take Table X.2.1 a= s example: Table X.2.1: Recommended configuration for T.38 SDP attribute values. T38FaxVersion Version 2 or higher. (NOTE 1) T38MaxBitRate 14 400 T38FaxFillBitRemoval FALSE (NOTE 2) T38FaxTranscodingMMR FALSE (NOTE 2) T38FaxTranscodingJBIG FALSE (NOTE 2) T38FaxRateManagement 'transferredTCF' T38FaxMaxBuffer 1800 T38FaxMaxDatagram At least 150 T38FaxMaxIFP 40 (NOTE 3) T38FaxUdpEC 't38UDPRedundancy' T38FaxUdpECDepth Minred: 1; Maxred: 2 (NOTE 3) T38FaxUdpFECMaxSpan 3 (NOTE 3) T38ModemType 't38G3FaxOnly' (NOTE 2, NOTE 3) NOTE 1: With Version 4, default values for the SDP attributes apply if t= he attributes are omitted. However, some values relate to capabilities of t= he remote CS FAX equipment unknown to the MGCF. NOTE 2: This value relates to capabilities of the remote CS FAX equipmen= t unknown to the MGCF. The recommended value (which is also the default val= ue in T.38 version 4) is likely to be supported by FAX equipment in CS netw= orks. NOTE 3: Only applicable for T.38 version 4. Would you agree? Albrecht From: Belling, Thomas (NSN - DE/Munich) [mailto:[email protected]] Sent: Donnerstag, 2. August 2012 11:03 To: Schwarz, Albrecht (Albrecht); [email protected] Subject: RE: H.248-controlled T.38 configurations: SDP- vs Property-based H= .248 signalling Hello Albrecht, a gateway could support FAX "transcoding", as I like to call it, and then u= se those parameters. But as Kevin wrote, it is highly unusual for MGW imple= mentations to do so. In my view we should not burden the MGW with such func= tionality and the benefit is also questionable, in particular because Kevin= believes the JBIG and NMR encoding are also rarely used by T.38 terminals.= I was rather envisioning a reframing of T.30 at the MGW. Reading your expl= anation that you support the default values I suspect this is also what you= r MGW does (as mine). Also in the table B.1 you attached those parameters a= re "optional". So, depending on MGW implementation, those could either be c= apabilities of the CS FAX equipment (if a reframing is done at the MGW as I= envision), or of the MGW (if the MGW performs FAX "transcoding"). For the 3GPP profiles, we do not necesarrily include any conceivable option= but only options with a real benefit. I would prefer not to include FAX "t= ranscoding" for the reasons outlined above. Assuming that we only want to u= se the default value, it does not need to be signalled to the MGW but can r= ather be a provisioned value. So I do not see a need to propagate those par= ameters over the Mn interface. Perhaps the NOTES should be phrased a bit clearer and include an explanatio= n that only T.30 reframing is included in the Mn profile and under this con= dition, those SDP attributes relate to capabilities of the CS FAX equipment= . Thomas From: 3GPP_TSG_CT_WG3 - Core Network and Terminals WG 3 [mailto:3GPP_TSG_CT= [email protected]] On Behalf Of ext Schwarz, Albrecht (Albrecht) Sent: Thursday, August 02, 2012 10:05 AM To: [email protected] Subject: Re: H.248-controlled T.38 configurations: SDP- vs Property-based H= .248 signalling Hello Thomas, I followed the SIP Forum FoIP thread, but I fail to see that confirmation t= owards remote G3FE. Actually it's rather the opposite, see Kevin's reply to you: > (I did not find any definition of MMR format apart from "Modified > Modified Read" in T.38. However on Annex VI of T.30, MMR is defined as > the T.6 encoding. This also matches explanations in Wikipedia) > > *T38FaxTranscodingJBIG*: Indicates the ability to convert to/from JBIG > to reduce bandwidth. This > > is a boolean parameter (inclusion =3D true, exclusion =3D false). It is possible for a T.30<->T.38 gateway to provide these behaviors if desi= red, and the resulting T.38 bitstream would differ in some noticeable ways = from the T.30 bitstream. However, based on discussions with various knowled= geable parties during our previous work in this group, it appears that it i= s highly unusual for a T.38 implementation (gateway or terminal) to actuall= y perform any of these three functions. =F0 it's a gateway capability! =F0 all your three referred T.38 parameters are subject of the IM-MGW impl= ementation! and ALU supports the recommended default values by Table H.2/T.38 (which sh= ould be inline with your proposal). Hence, Kevin explicitly confirms this also as gateway capability! Regards, Albrecht From: Belling, Thomas (NSN - DE/Munich) [mailto:[email protected]] Sent: Mittwoch, 1. August 2012 16:46 To: Schwarz, Albrecht (Albrecht); [email protected]<mailto:3GPP= [email protected]> Subject: RE: H.248-controlled T.38 configurations: SDP- vs Property-based H= .248 signalling Dear Albrecht, Thanks for your comments. with respect to T38FaxFillBitRemoval, T38FaxTranscodingMMR and T38FaxTransc= odingJBIG SDP attributes, to which Notes 1 and 2 relate, I had some discus= sions at the SIP forum FoIP mailing list as you suggested. And it was confirmed that unless you do some "transcoding" of the payload w= ithin T.38 at the MGW, those properties relate to the remote CS FAX endpoin= t. However, people thought that not signaling those properties in H.248v4 m= ight be OK, because the default values which then apply are likely to be su= pported by any receiving CS endpoint. The only open issue where I did not y= et receive any reply is whether any harm is done if the CS endpoint behaves= differently when sending. Thomas From: 3GPP_TSG_CT_WG3 - Core Network and Terminals WG 3 [mailto:3GPP_TSG_CT= [email protected]] On Behalf Of ext Schwarz, Albrecht (Albrecht) Sent: Wednesday, August 01, 2012 4:17 PM To: [email protected]<mailto:[email protected]> Subject: H.248-controlled T.38 configurations: SDP- vs Property-based H.248= signalling [Cc'd megaco list due to H.248.2] The T.38 parameters as defined by ITU-T T.38 are related to a T.38 endpoint= implementation, such as the T.38 user plane interworking function as e.g. = located in an H.248 IP-to-TDM media gateway (e.g. 3GPP IM-MGW). There are fundamentally two signaling options for such T.38 configurations: 1. SDP-based: using T.38 Annex D defined SDP elements embedded in H.248 d= escriptors 2. Property-based: using H.248.2, IP Fax package defined properties, such= as specified by clauses 10.1.3 to 10.1.7 Both H.248 signalling options are basically equivalent, - independent of SD= P- or Property-based signaling elements. The signaling elements relate to t= he T.38 endpoint, but NOT to any remote G3FE. [Note: the H.248 IP fax package version 1 (from 2005/2007) does not yet con= tain the latest T.38V4 (2010) parameter. But this aspect is irrelevant in t= his discussion due to the proposal in 3GPP for the SDP-based method.] Thus, all "T.38 SDP attributes" (in C3-121327) are related to gateway capabilitie= s (such as supported T.38 configurations by an IM-MGW implementation) (NOTE= : attached is T.38 Table B.1 for H.323 gateways, which again underlines the= relation to gateway capabilities). The MGC / MGCF may be either 1. aware of the supported T.38 configuration(s) by his associated MGs or 2. unaware. Awareness may be achieved via auditing or configuration management. Unawareness is basically possible, but may lead to inefficient or even inef= fective H.248 scenarios for T.38. Dependent on the amount of "supported T.38 configuration(s)" knowledge at M= GC level would be the content of the SIP-level SDP O/A procedures. Conclusions for C3-121327 (http://www.3gpp.org/ftp/tsg_ct/WG3_interworking_= ex-CN3/TSGC3_70_Chicago/Docs/C3-121327.zip): NOTEs 1 and 2 in Table X.3.1 are incorrect in my opinion. The text related to "remote CS FAX equipment" (term should be anyway replac= ed by term G3FE) should be just deleted. And there would be correspondent c= hanges at other tables. -Albrecht --_000_5F7BCCF5541B7444830A2288ABBEBC96218B57EDB5FRMRSSXCHMBSD_ Content-Type: text/html; charset="iso-8859-1" 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=3DContent-Type content= =3D"text/html; charset=3Diso-8859-1"><meta name=3DGenerator content=3D"Micr= osoft Word 12 (filtered medium)"><style><!-- /* Font Definitions */ @font-face {font-family:Wingdings; panose-1:5 0 0 0 0 0 0 0 0 0;} @font-face {font-family:Batang; panose-1:2 3 6 0 0 1 1 1 1 1;} @font-face {font-family:Batang; panose-1:2 3 6 0 0 1 1 1 1 1;} @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;} @font-face {font-family:"\@Batang"; 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(NOTE 1)<o:p></o:p></span></p></td></tr><tr><td width=3D285 valign= =3Dtop style=3D'width:213.4pt;border-top:none;border-left:solid windowtext = 1.5pt;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.= 0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><b><span lang=3DEN-GB>T38Ma= xBitRate<o:p></o:p></span></b></p></td><td width=3D354 valign=3Dtop style= =3D'width:265.45pt;border-top:none;border-left:none;border-bottom:solid win= dowtext 1.0pt;border-right:solid windowtext 1.5pt;padding:0cm 5.4pt 0cm 5.4= pt'><p class=3DTAL><span lang=3DEN-GB>14 400<span style=3D'color:black'><o:= p></o:p></span></span></p></td></tr><tr><td width=3D285 valign=3Dtop style= =3D'width:213.4pt;border-top:none;border-left:solid windowtext 1.5pt;border= -bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:= 0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><b><span lang=3DEN-GB>T38FaxFillBitRemo= val<o:p></o:p></span></b></p></td><td width=3D354 valign=3Dtop style=3D'wid= th:265.45pt;border-top:none;border-left:none;border-bottom:solid windowtext= 1.0pt;border-right:solid windowtext 1.5pt;padding:0cm 5.4pt 0cm 5.4pt'><p = class=3DTAL><span lang=3DEN-GB>FALSE <s>(NOTE 2)</s><o:p></o:p></span></p><= /td></tr><tr><td width=3D285 valign=3Dtop style=3D'width:213.4pt;border-top= :none;border-left:solid windowtext 1.5pt;border-bottom:solid windowtext 1.0= pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p clas= s=3DTAL><b><span lang=3DEN-GB>T38FaxTranscodingMMR<o:p></o:p></span></b></p= ></td><td width=3D354 valign=3Dtop style=3D'width:265.45pt;border-top:none;= border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid wi= ndowtext 1.5pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><span lang=3DEN-= GB>FALSE <s>(NOTE 2)</s><o:p></o:p></span></p></td></tr><tr><td width=3D285= valign=3Dtop style=3D'width:213.4pt;border-top:none;border-left:solid wind= owtext 1.5pt;border-bottom:solid windowtext 1.0pt;border-right:solid window= text 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><b><span lang=3DEN-G= B>T38FaxTranscodingJBIG<o:p></o:p></span></b></p></td><td width=3D354 valig= n=3Dtop style=3D'width:265.45pt;border-top:none;border-left:none;border-bot= tom:solid windowtext 1.0pt;border-right:solid windowtext 1.5pt;padding:0cm = 5.4pt 0cm 5.4pt'><p class=3DTAL><span lang=3DEN-GB>FALSE <s>(NOTE 2)</s><o:= p></o:p></span></p></td></tr><tr><td width=3D285 valign=3Dtop style=3D'widt= h:213.4pt;border-top:none;border-left:solid windowtext 1.5pt;border-bottom:= solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4p= t 0cm 5.4pt'><p class=3DTAL><b><span lang=3DEN-GB>T38FaxRateManagement<o:p>= </o:p></span></b></p></td><td width=3D354 valign=3Dtop style=3D'width:265.4= 5pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;b= order-right:solid windowtext 1.5pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3D= TAL><span lang=3DEN-GB>'transferredTCF'<o:p></o:p></span></p></td></tr><tr>= <td width=3D285 valign=3Dtop style=3D'width:213.4pt;border-top:none;border-= left:solid windowtext 1.5pt;border-bottom:solid windowtext 1.0pt;border-rig= ht:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><b><s= pan lang=3DEN-GB>T38FaxMaxBuffer<o:p></o:p></span></b></p></td><td width=3D= 354 valign=3Dtop style=3D'width:265.45pt;border-top:none;border-left:none;b= order-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.5pt;pad= ding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><span lang=3DEN-GB>1800<span style= =3D'color:black'><o:p></o:p></span></span></p></td></tr><tr><td width=3D285= valign=3Dtop style=3D'width:213.4pt;border-top:none;border-left:solid wind= owtext 1.5pt;border-bottom:solid windowtext 1.0pt;border-right:solid window= text 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><b><span lang=3DEN-G= B>T38FaxMaxDatagram<o:p></o:p></span></b></p></td><td width=3D354 valign=3D= top style=3D'width:265.45pt;border-top:none;border-left:none;border-bottom:= solid windowtext 1.0pt;border-right:solid windowtext 1.5pt;padding:0cm 5.4p= t 0cm 5.4pt'><p class=3DTAL><span lang=3DEN-GB>At least 150<o:p></o:p></spa= n></p></td></tr><tr><td width=3D285 valign=3Dtop style=3D'width:213.4pt;bor= der-top:none;border-left:solid windowtext 1.5pt;border-bottom:solid windowt= ext 1.0pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'>= <p class=3DTAL><b><span lang=3DEN-GB>T38FaxMaxIFP<o:p></o:p></span></b></p>= </td><td width=3D354 valign=3Dtop style=3D'width:265.45pt;border-top:none;b= order-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid win= dowtext 1.5pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><span lang=3DEN-G= B>40 (NOTE 3)<o:p></o:p></span></p></td></tr><tr><td width=3D285 valign=3Dt= op style=3D'width:213.4pt;border-top:none;border-left:solid windowtext 1.5p= t;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;= padding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><b><span lang=3DEN-GB>T38FaxUdp= EC<o:p></o:p></span></b></p></td><td width=3D354 valign=3Dtop style=3D'widt= h:265.45pt;border-top:none;border-left:none;border-bottom:solid windowtext = 1.0pt;border-right:solid windowtext 1.5pt;padding:0cm 5.4pt 0cm 5.4pt'><p c= lass=3DTAL><span lang=3DEN-GB>'t38UDPRedundancy'<o:p></o:p></span></p></td>= </tr><tr><td width=3D285 valign=3Dtop style=3D'width:213.4pt;border-top:non= e;border-left:solid windowtext 1.5pt;border-bottom:solid windowtext 1.0pt;b= order-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3D= TAL><b><span lang=3DEN-GB>T38FaxUdpECDepth<o:p></o:p></span></b></p></td><t= d width=3D354 valign=3Dtop style=3D'width:265.45pt;border-top:none;border-l= eft:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext= 1.5pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><span lang=3DEN-GB>Minre= d: 1; Maxred: 2 (NOTE 3)<o:p></o:p></span></p></td></tr><tr><td width=3D285= valign=3Dtop style=3D'width:213.4pt;border-top:none;border-left:solid wind= owtext 1.5pt;border-bottom:solid windowtext 1.0pt;border-right:solid window= text 1.0pt;padding:0cm 5.4pt 0cm 5.4pt;border-top:none !msorm;border-left:s= olid windowtext 1.5pt !msorm;border-bottom:solid windowtext 1.0pt !msorm;bo= rder-right:solid windowtext 1.0pt !msorm;padding:0cm 5.4pt 0cm 5.4pt !msorm= '><p class=3DTAL><b><span lang=3DEN-GB>T38FaxUdpFECMaxSpan<o:p></o:p></span= ></b></p></td><td width=3D354 valign=3Dtop style=3D'width:265.45pt;border-t= op:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:= solid windowtext 1.5pt;padding:0cm 5.4pt 0cm 5.4pt;border-top:solid windowt= ext 1.0pt !msorm;border-left:none !msorm;border-bottom:solid windowtext 1.0= pt !msorm;border-right:solid windowtext 1.5pt !msorm;padding:0cm 5.4pt 0cm = 5.4pt !msorm'><p class=3DTAL><span lang=3DEN-GB>3 (NOTE 3)<o:p></o:p></span= ></p></td></tr><tr><td width=3D285 valign=3Dtop style=3D'width:213.4pt;bord= er-top:none;border-left:solid windowtext 1.5pt;border-bottom:solid windowte= xt 1.5pt;border-right:solid windowtext 1.0pt;padding:0cm 5.4pt 0cm 5.4pt'><= p class=3DTAL><b><span lang=3DEN-GB>T38ModemType<o:p></o:p></span></b></p><= /td><td width=3D354 valign=3Dtop style=3D'width:265.45pt;border-top:none;bo= rder-left:none;border-bottom:solid windowtext 1.5pt;border-right:solid wind= owtext 1.5pt;padding:0cm 5.4pt 0cm 5.4pt'><p class=3DTAL><span lang=3DEN-GB= >'t38G3FaxOnly' (<s>NOTE 2,</s> NOTE 3)<o:p></o:p></span></p></td></tr><tr>= <td width=3D638 colspan=3D2 valign=3Dtop style=3D'width:478.85pt;border:sol= id windowtext 1.5pt;border-top:none;padding:0cm 5.4pt 0cm 5.4pt'><p class= =3DTAN><span lang=3DEN-GB>NOTE 1:=A0=A0=A0 With Version 4, default values f= or the SDP attributes apply if the attributes are omitted. <s>However, some= values relate to capabilities of the remote CS FAX equipment unknown to th= e MGCF.</s></span><span lang=3DEN-GB><o:p></o:p></span></p><p class=3DTAN><= s><span lang=3DEN-GB>NOTE 2:=A0=A0=A0 This value relates to capabilities of= the remote CS FAX equipment unknown to the MGCF. The recommended value (wh= ich is also the default value in T.38 version 4) is likely to be supported = by FAX equipment in CS networks.<o:p></o:p></span></s></p><p class=3DTAN><s= pan lang=3DEN-GB>NOTE 3: =A0=A0 Only applicable for T.38 version 4.<o:p></o= :p></span></p></td></tr></table></div><p class=3DMsoNormal><span lang=3DEN-= GB style=3D'font-size:10.0pt'><o:p> </o:p></span></p><p class=3DMsoNor= mal><span lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier New";= color:#003300'>Would you agree?<o:p></o:p></span></p><p class=3DMsoNormal><= span lang=3DEN-GB style=3D'font-size:10.0pt;font-family:"Courier New";color= :#003300'>Albrecht<o:p></o:p></span></p><p class=3DMsoNormal><span lang=3DE= N-US style=3D'font-size:10.0pt;font-family:"Courier New";color:#003300'><o:= p> </o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'f= ont-size:10.0pt;font-family:"Courier New";color:#003300'><o:p> </o:p><= /span></p><div><div style=3D'border:none;border-top:solid #B5C4DF 1.0pt;pad= ding:3.0pt 0cm 0cm 0cm'><p class=3DMsoNormal><b><span lang=3DEN-US style=3D= 'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span = lang=3DEN-US style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'> = Belling, Thomas (NSN - DE/Munich) [mailto:[email protected]] <br><b>Se= nt:</b> Donnerstag, 2. August 2012 11:03<br><b>To:</b> Schwarz, Albrecht (A= lbrecht); [email protected]<br><b>Subject:</b> RE: H.248-contro= lled T.38 configurations: SDP- vs Property-based H.248 signalling<o:p></o:p= ></span></p></div></div><p class=3DMsoNormal><o:p> </o:p></p><p class= =3DMsoNormal><span lang=3DEN-US style=3D'font-size:11.0pt;font-family:"Cali= bri","sans-serif";color:#1F497D'>Hello Albrecht,<o:p></o:p></span></p><p cl= ass=3DMsoNormal><span lang=3DEN-US style=3D'font-size:11.0pt;font-family:"C= alibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=3D= MsoNormal><span lang=3DEN-US style=3D'font-size:11.0pt;font-family:"Calibri= ","sans-serif";color:#1F497D'>a gateway could support FAX “transcodin= g”, as I like to call it, and then use those parameters. But as Kevin= wrote, it is highly unusual for MGW implementations to do so. In my view w= e should not burden the MGW with such functionality and the benefit is also= questionable, in particular because Kevin believes the JBIG and NMR encodi= ng are also rarely used by T.38 terminals. I was rather envisioning a refra= ming of T.30 at the MGW. Reading your explanation that you support the defa= ult values I suspect this is also what your MGW does (as mine). Also in the= table B.1 you attached those parameters are “optional”. So, de= pending on MGW implementation, those could either be capabilities of the CS= FAX equipment (if a reframing is done at the MGW as I envision), or of the= MGW (if the MGW performs FAX “transcoding”).<o:p></o:p></span>= </p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p= class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:11.0pt;font-family= :"Calibri","sans-serif";color:#1F497D'>For the 3GPP profiles, we do not nec= esarrily include any conceivable option but only options with a real benefi= t. I would prefer not to include FAX “transcoding” for the reas= ons outlined above. Assuming that we only want to use the default value, it= does not need to be signalled to the MGW but can rather be a provisioned v= alue. So I do not see a need to propagate those parameters over the Mn inte= rface.<o:p></o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US style= =3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p= > </o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'fo= nt-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Perhaps th= e NOTES should be phrased a bit clearer and include an explanation that onl= y T.30 reframing is included in the Mn profile and under this condition, th= ose SDP attributes relate to capabilities of the CS FAX equipment.<o:p></o:= p></span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:11.= 0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></sp= an></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:11.0pt;fo= nt-family:"Calibri","sans-serif";color:#1F497D'>Thomas<o:p></o:p></span></p= ><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:11.0pt;font-fam= ily:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p cl= ass=3DMsoNormal><span style=3D'font-size:11.0pt;font-family:"Calibri","sans= -serif";color:#1F497D'><o:p> </o:p></span></p><p class=3DMsoNormal><sp= an style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F49= 7D'><o:p> </o:p></span></p><div><div style=3D'border:none;border-top:s= olid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=3DMsoNormal><b><span= lang=3DEN-US style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>= From:</span></b><span lang=3DEN-US style=3D'font-size:10.0pt;font-family:"T= ahoma","sans-serif"'> 3GPP_TSG_CT_WG3 - Core Network and Terminals WG 3 [ma= ilto:[email protected]] <b>On Behalf Of </b>ext Schwarz, Albrec= ht (Albrecht)<br><b>Sent:</b> Thursday, August 02, 2012 10:05 AM<br><b>To:<= /b> [email protected]<br><b>Subject:</b> Re: H.248-controlled T= .38 configurations: SDP- vs Property-based H.248 signalling<o:p></o:p></spa= n></p></div></div><p class=3DMsoNormal><o:p> </o:p></p><p class=3DMsoN= ormal><span lang=3DEN-US style=3D'font-size:10.0pt;font-family:"Courier New= ";color:#993366'>Hello Thomas,<o:p></o:p></span></p><p class=3DMsoNormal><s= pan lang=3DEN-US style=3D'font-size:10.0pt;font-family:"Courier New";color:= #993366'><o:p> </o:p></span></p><p class=3DMsoNormal><span lang=3DEN-U= S style=3D'font-size:10.0pt;font-family:"Courier New";color:#993366'>I foll= owed the SIP Forum FoIP thread, but I fail to see that confirmation towards= remote G3FE.<o:p></o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US = style=3D'font-size:10.0pt;font-family:"Courier New";color:#993366'>Actually= it’s rather the opposite, see Kevin’s reply to you:<o:p></o:p>= </span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:10.0p= t;font-family:"Courier New";color:#993366'><o:p> </o:p></span></p><p c= lass=3DMsoPlainText><span lang=3DEN-US>> (I did not find any definition = of MMR format apart from “Modified <o:p></o:p></span></p><p class=3DM= soPlainText><span lang=3DEN-US>> Modified Read” in T.38. However o= n Annex VI of T.30, MMR is defined as <o:p></o:p></span></p><p class=3DMsoP= lainText><span lang=3DEN-US>> the T.6 encoding. This also matches explan= ations in Wikipedia)<o:p></o:p></span></p><p class=3DMsoPlainText><span lan= g=3DEN-US>><o:p> </o:p></span></p><p class=3DMsoPlainText><span lan= g=3DEN-US>> *T38FaxTranscodingJBIG*: Indicates the ability to convert to= /from JBIG <o:p></o:p></span></p><p class=3DMsoPlainText><span lang=3DEN-US= >> to reduce bandwidth. This<o:p></o:p></span></p><p class=3DMsoPlainTex= t><span lang=3DEN-US>><o:p> </o:p></span></p><p class=3DMsoPlainTex= t><span lang=3DEN-US>> is a boolean parameter (inclusion =3D true, exclu= sion =3D false).<o:p></o:p></span></p><p class=3DMsoPlainText><span lang=3D= EN-US><o:p> </o:p></span></p><p class=3DMsoPlainText><span lang=3DEN-U= S>It is <span style=3D'color:red'>possible for a T.30<->T.38 gateway<= /span> to <span style=3D'color:red'>provide these behaviors if desired</spa= n>, and the resulting T.38 bitstream would differ in some noticeable ways f= rom the T.30 bitstream. However, based on discussions with various knowledg= eable parties during our previous work in this group, it appears that it is= highly unusual for a T.38 implementation (gateway or terminal) to actually= perform any of these three functions.<o:p></o:p></span></p><p class=3DMsoN= ormal><span lang=3DEN-US style=3D'font-size:10.0pt;font-family:"Courier New= ";color:#993366'><o:p> </o:p></span></p><p class=3DMsoNormal><span lan= g=3DEN-US style=3D'font-size:10.0pt;font-family:"Courier New";color:#993366= '><o:p> </o:p></span></p><p class=3DMsoListParagraph style=3D'text-ind= ent:-18.0pt;mso-list:l1 level1 lfo2'><![if !supportLists]><span lang=3DEN-U= S style=3D'font-size:10.0pt;font-family:Wingdings;color:#993366'><span styl= e=3D'mso-list:Ignore'>=F0<span style=3D'font:7.0pt "Times New Roman"'> = ; </span></span></span><![endif]><span lang=3DEN-US style=3D'font-size:10.0= pt;font-family:"Courier New";color:#993366'>it’s a gateway capability= !<o:p></o:p></span></p><p class=3DMsoListParagraph style=3D'text-indent:-18= .0pt;mso-list:l1 level1 lfo2'><![if !supportLists]><span lang=3DEN-US style= =3D'font-size:10.0pt;font-family:Wingdings;color:#993366'><span style=3D'ms= o-list:Ignore'>=F0<span style=3D'font:7.0pt "Times New Roman"'> </spa= n></span></span><![endif]><span lang=3DEN-US style=3D'font-size:10.0pt;font= -family:"Courier New";color:#993366'>all your three referred T.38 parameter= s are subject of the IM-MGW implementation!<o:p></o:p></span></p><p class= =3DMsoNormal><span lang=3DEN-US style=3D'font-size:10.0pt;font-family:"Cour= ier New";color:#993366'>and ALU supports the recommended default values by = Table H.2/T.38 (which should be inline with your proposal).<o:p></o:p></spa= n></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:10.0pt;fon= t-family:"Courier New";color:#993366'><o:p> </o:p></span></p><p class= =3DMsoNormal><span lang=3DEN-US style=3D'font-size:10.0pt;font-family:"Cour= ier New";color:#993366'>Hence, Kevin explicitly confirms this also as gatew= ay capability!<o:p></o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US= style=3D'font-size:10.0pt;font-family:"Courier New";color:#993366'><o:p>&n= bsp;</o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-= size:10.0pt;font-family:"Courier New";color:#993366'>Regards,<o:p></o:p></s= pan></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:10.0pt;f= ont-family:"Courier New";color:#993366'>Albrecht<o:p></o:p></span></p><p cl= ass=3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Courier New";c= olor:#993366'><o:p> </o:p></span></p><p class=3DMsoNormal><span style= =3D'font-size:10.0pt;font-family:"Courier New";color:#993366'><o:p> </= o:p></span></p><p class=3DMsoNormal><span style=3D'font-size:10.0pt;font-fa= mily:"Courier New";color:#993366'><o:p> </o:p></span></p><p class=3DMs= oNormal><span style=3D'font-size:10.0pt;font-family:"Courier New";color:#99= 3366'><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=3DMsoNormal><b><sp= an lang=3DEN-US style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"= '>From:</span></b><span lang=3DEN-US style=3D'font-size:10.0pt;font-family:= "Tahoma","sans-serif"'> Belling, Thomas (NSN - DE/Munich) [<a href=3D"mailt= o:[email protected]">mailto:[email protected]</a>] <br><b>Sent:</= b> Mittwoch, 1. August 2012 16:46<br><b>To:</b> Schwarz, Albrecht (Albrecht= ); <a href=3D"mailto:[email protected]">[email protected]= SI.ORG</a><br><b>Subject:</b> RE: H.248-controlled T.38 configurations: SDP= - vs Property-based H.248 signalling<o:p></o:p></span></p></div></div><p cl= ass=3DMsoNormal><o:p> </o:p></p><p class=3DMsoNormal><span lang=3DEN-U= S style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497= D'>Dear Albrecht,<o:p></o:p></span></p><p class=3DMsoNormal><span lang=3DEN= -US style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F4= 97D'><o:p> </o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US st= yle=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>T= hanks for your comments.<o:p></o:p></span></p><p class=3DMsoNormal><span la= ng=3DEN-US style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";col= or:#1F497D'><o:p> </o:p></span></p><p class=3DMsoNormal><span lang=3DE= N-US style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F= 497D'>with respect to T38FaxFillBitRemoval, T38FaxTranscodingMMR and T38Fax= TranscodingJBIG SDP attributes, to which Notes 1 and 2 relate, I had = some discussions at the SIP forum FoIP mailing list as you suggested.<o:p><= /o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:= 11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p><= /span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:11.0pt= ;font-family:"Calibri","sans-serif";color:#1F497D'>And it was confirmed tha= t unless you do some “transcoding” of the payload within T.38 a= t the MGW, those properties relate to the remote CS FAX endpoint. However, = people thought that not signaling those properties in H.248v4 might be OK, = because the default values which then apply are likely to be supported by a= ny receiving CS endpoint. The only open issue where I did not yet receive a= ny reply is whether any harm is done if the CS endpoint behaves differently= when sending.<o:p></o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US= style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D= '><o:p> </o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US style= =3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thom= as<o:p></o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'fo= nt-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> = ;</o:p></span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-siz= e:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p= ></span></p><p class=3DMsoNormal><span lang=3DEN-US style=3D'font-size:11.0= pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></spa= n></p><div><div style=3D'border:none;border-top:solid #B5C4DF 1.0pt;padding= :3.0pt 0cm 0cm 0cm'><p class=3DMsoNormal><b><span lang=3DEN-US style=3D'fon= t-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang= =3DEN-US style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'> 3GPP= _TSG_CT_WG3 - Core Network and Terminals WG 3 [<a href=3D"mailto:3GPP_TSG_C= [email protected]">mailto:[email protected]</a>] <b>On Behalf= Of </b>ext Schwarz, Albrecht (Albrecht)<br><b>Sent:</b> Wednesday, August = 01, 2012 4:17 PM<br><b>To:</b> <a href=3D"mailto:[email protected].= ORG">[email protected]</a><br><b>Subject:</b> H.248-controlled = T.38 configurations: SDP- vs Property-based H.248 signalling<o:p></o:p></sp= an></p></div></div><p class=3DMsoNormal><o:p> </o:p></p><div><p class= =3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Courier New";colo= r:#002060'>[Cc’d megaco list due to H.248.2]</span><span style=3D'fon= t-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p></div><div><= p class=3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Courier Ne= w";color:#002060'> </span><span style=3D'font-size:10.0pt;font-family:= "Courier New"'><o:p></o:p></span></p></div><div><p class=3DMsoNormal><span = style=3D'font-size:10.0pt;font-family:"Courier New";color:#002060'>The <b>T= .38 parameters</b> as defined by ITU-T T.38 are related to a <b>T.38 endpoi= nt implementation</b>, such as the <b>T.38 user plane interworking function= </b> as e.g. located in an H.248 IP-to-TDM media gateway (e.g. 3GPP IM-MGW)= .</span><span style=3D'font-size:10.0pt;font-family:"Courier New"'><o:p></o= :p></span></p></div><div><p class=3DMsoNormal><span style=3D'font-size:10.0= pt;font-family:"Courier New";color:#002060'> </span><span style=3D'fon= t-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p></div><div><= p class=3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Courier Ne= w";color:#002060'>There are fundamentally two signaling options for such T.= 38 configurations:</span><span style=3D'font-size:10.0pt;font-family:"Couri= er New"'><o:p></o:p></span></p></div><ol start=3D1 type=3Da><li class=3DMso= Normal style=3D'color:#002060;mso-margin-top-alt:auto;mso-margin-bottom-alt= :auto;mso-list:l2 level1 lfo5'><b><span style=3D'font-size:10.0pt;font-fami= ly:"Courier New"'>SDP-based</span></b><span style=3D'font-size:10.0pt;font-= family:"Courier New"'>: using <b>T.38 Annex D</b> defined SDP elements embe= dded in H.248 descriptors<o:p></o:p></span></li><li class=3DMsoNormal style= =3D'color:#002060;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-li= st:l2 level1 lfo5'><b><span style=3D'font-size:10.0pt;font-family:"Courier = New"'>Property-based</span></b><span style=3D'font-size:10.0pt;font-family:= "Courier New"'>: using <b>H.248.2, IP Fax package</b> defined properties, s= uch as specified by clauses 10.1.3 to 10.1.7<o:p></o:p></span></li></ol><di= v><p class=3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Calibri= ","sans-serif";color:#002060'> </span><span style=3D'font-size:10.0pt;= font-family:"Courier New"'><o:p></o:p></span></p></div><div><p class=3DMsoN= ormal><span style=3D'font-size:10.0pt;font-family:"Courier New";color:#0020= 60'>Both H.248 signalling options are basically equivalent, - independent o= f SDP- or Property-based signaling elements. The signaling elements relate = to the T.38 endpoint, but NOT to any remote G3FE.</span><span style=3D'font= -size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p></div><div><p= class=3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Courier New= ";color:#002060'>[Note: the H.248 IP fax package version 1 (from 2005/2007)= does not yet contain the latest T.38V4 (2010) parameter. But this aspect i= s irrelevant in this discussion due to the proposal in 3GPP for the SDP-bas= ed method.]</span><span style=3D'font-size:10.0pt;font-family:"Courier New"= '><o:p></o:p></span></p></div><div><p class=3DMsoNormal><span style=3D'font= -size:10.0pt;font-family:"Calibri","sans-serif";color:#002060'> </span= ><span style=3D'font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></sp= an></p></div><div><p class=3DMsoNormal><span style=3D'font-size:10.0pt;font= -family:"Courier New";color:#002060'>Thus,</span><span style=3D'font-size:1= 0.0pt;font-family:"Courier New"'><o:p></o:p></span></p></div><div><p class= =3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Courier New";colo= r:#002060'>all “T.38 SDP attributes” (in C3-121327) are related= to gateway capabilities (such as supported T.38 configurations by an IM-MG= W implementation) (NOTE: attached is T.38 Table B.1 for H.323 gateways, whi= ch again underlines the relation to gateway capabilities).</span><span styl= e=3D'font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p></di= v><div><p class=3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Co= urier New";color:#002060'>The MGC / MGCF may be either</span><span style=3D= 'font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p></div><o= l start=3D1 type=3Da><li class=3DMsoNormal style=3D'color:#002060;mso-margi= n-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo8'><span st= yle=3D'font-size:10.0pt;font-family:"Courier New"'>aware of the supported T= .38 configuration(s) by his associated MGs or<o:p></o:p></span></li><li cla= ss=3DMsoNormal style=3D'color:#002060;mso-margin-top-alt:auto;mso-margin-bo= ttom-alt:auto;mso-list:l0 level1 lfo8'><span style=3D'font-size:10.0pt;font= -family:"Courier New"'>unaware.<o:p></o:p></span></li></ol><div><p class=3D= MsoNormal><span style=3D'font-size:10.0pt;font-family:"Courier New";color:#= 002060'>Awareness may be achieved via auditing or configuration management.= </span><span style=3D'font-size:10.0pt;font-family:"Courier New"'><o:p></o:= p></span></p></div><div><p class=3DMsoNormal><span style=3D'font-size:10.0p= t;font-family:"Courier New";color:#002060'>Unawareness is basically possibl= e, but may lead to inefficient or even ineffective H.248 scenarios for T.38= .</span><span style=3D'font-size:10.0pt;font-family:"Courier New"'><o:p></o= :p></span></p></div><div><p class=3DMsoNormal><span style=3D'font-size:10.0= pt;font-family:"Courier New";color:#002060'>Dependent on the amount of R= 20;supported T.38 configuration(s)” knowledge at MGC level would be t= he content of the SIP-level SDP O/A procedures.</span><span style=3D'font-s= ize:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p></div><div><p c= lass=3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Calibri","san= s-serif";color:#002060'> </span><span style=3D'font-size:10.0pt;font-f= amily:"Courier New"'><o:p></o:p></span></p></div><div><p class=3DMsoNormal>= <span style=3D'font-size:10.0pt;font-family:"Courier New";color:#002060'>Co= nclusions for <b>C3-121327</b> (<a href=3D"http://www.3gpp.org/ftp/tsg_ct/W= G3_interworking_ex-CN3/TSGC3_70_Chicago/Docs/C3-121327.zip">http://www.3gpp= .org/ftp/tsg_ct/WG3_interworking_ex-CN3/TSGC3_70_Chicago/Docs/C3-121327.zip= </a>):</span><span style=3D'font-size:10.0pt;font-family:"Courier New"'><o:= p></o:p></span></p></div><div><p class=3DMsoNormal><span style=3D'font-size= :10.0pt;font-family:"Courier New";color:#002060'>NOTEs 1 and 2 in Table X.3= .1 are incorrect in my opinion.</span><span style=3D'font-size:10.0pt;font-= family:"Courier New"'><o:p></o:p></span></p></div><div><p class=3DMsoNormal= ><span style=3D'font-size:10.0pt;font-family:"Courier New";color:#002060'>T= he <b>text</b> related to “remote CS FAX equipment” (term shoul= d be anyway replaced by term G3FE) should be just <b>deleted</b>. And there= would be correspondent changes at other tables.</span><span style=3D'font-= size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p></div><div><p = class=3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Calibri","sa= ns-serif";color:#002060'> </span><span style=3D'font-size:10.0pt;font-= family:"Courier New"'><o:p></o:p></span></p></div><div><p class=3DMsoNormal= ><span style=3D'font-size:10.0pt;font-family:"Courier New";color:#002060'>-= Albrecht</span><span style=3D'font-size:10.0pt;font-family:"Courier New"'><= o:p></o:p></span></p></div><div><p class=3DMsoNormal><span style=3D'font-si= ze:10.0pt;font-family:"Calibri","sans-serif";color:#002060'> </span><s= pan style=3D'font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span>= </p></div><div><p class=3DMsoNormal><span style=3D'font-size:10.0pt;font-fa= mily:"Calibri","sans-serif";color:#C00000'> </span><span style=3D'font= -size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p></div><div><p= class=3DMsoNormal><span style=3D'font-size:10.0pt;font-family:"Courier New= "'><o:p> </o:p></span></p></div><div><p class=3DMsoNormal><span style= =3D'font-size:10.0pt;font-family:"Calibri","sans-serif"'> </span><span= style=3D'font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p= ></div></div></body></html>= --_000_5F7BCCF5541B7444830A2288ABBEBC96218B57EDB5FRMRSSXCHMBSD_-- --===============8511541477297440520== 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 --===============8511541477297440520==--