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<DIV><FONT face=Arial>Kevin,</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Indeed, it was a typo made by somebody, but whatever
effort was made to inform all vendors was insufficient as I have yet to find a
single vendors actually confess to be shipping T.38 products with the 2002
syntax.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>There are no implementers guides or other public documents
available on the ITU web site on the topic. The first published document
available to the public was dated May 2001. That's 3 years following
standardization which, in my opinion, is far too late to be
making elementary ASN.1 changes-- even if there was good
intention.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>I think we have to resolve this issue through some kind of
versioning of the protocol.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Paul</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=kboyle@NORTELNETWORKS.COM
href="mailto:kboyle@NORTELNETWORKS.COM">Kevin Boyle</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=ITU-SG16@echo.jf.INTEL.COM
href="mailto:ITU-SG16@echo.jf.INTEL.COM">ITU-SG16@echo.jf.INTEL.COM</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, March 14, 2003 9:15
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: T.38 potentially broken by
recent Corrigendum</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=712071214-14032003><FONT face=Arial color=#0000ff
size=2>All,</FONT></SPAN></DIV>
<DIV><SPAN class=712071214-14032003></SPAN> </DIV>
<DIV><SPAN class=712071214-14032003></SPAN><SPAN
class=712071214-14032003><FONT face=Arial color=#0000ff size=2>It is my
understanding that the ellipsis was intended to be there, and that it
wasn't until folks started implementing that it was noticed that it
got dropped somewhere between the editor's hands and publication. There
was a TD in the Feb 2000 meeting noting this typo. I can
produce it if anyone wants to see it.</FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2></FONT> </DIV>
<DIV><FONT face=Arial><FONT color=#0000ff><FONT size=2>It is<SPAN
class=712071214-14032003> also my understanding that care was taken to ensure
that all known vendors were made aware of the change at the
time.</SPAN></FONT></FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT color=#0000ff><FONT size=2><SPAN
class=712071214-14032003></SPAN></FONT></FONT></FONT> </DIV>
<DIV><FONT face=Arial><FONT color=#0000ff><FONT size=2><SPAN
class=712071214-14032003>Kevin</SPAN></FONT></FONT></FONT></SPAN></DIV>
<BLOCKQUOTE style="MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B> Klaghofer Karl
ICN EN HS D 11 [mailto:karl.klaghofer@SIEMENS.COM] <BR><B>Sent:</B> Friday,
March 14, 2003 3:44 AM<BR><B>To:</B>
ITU-SG16@echo.jf.INTEL.COM<BR><B>Subject:</B> AW: T.38 potentially broken by
recent Corrigendum<BR><BR></FONT></DIV>
<DIV><SPAN class=420224008-14032003><FONT face=Arial color=#0000ff
size=2>Paul,</FONT></SPAN></DIV>
<DIV><SPAN class=420224008-14032003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=420224008-14032003><FONT face=Arial color=#0000ff size=2>I
fully agree with you, that the T.38 (1998) asn.1 and the Revision of T.38
(2002) asn.1 needs to be backwards compatible. </FONT></SPAN></DIV>
<DIV><SPAN class=420224008-14032003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=420224008-14032003><FONT face=Arial color=#0000ff
size=2>Regards,</FONT></SPAN></DIV>
<DIV><SPAN class=420224008-14032003><FONT face=Arial color=#0000ff
size=2>Karl Klaghofer</FONT></SPAN></DIV>
<DIV><SPAN class=420224008-14032003><FONT face=Arial color=#0000ff
size=2>Siemens</FONT></SPAN></DIV>
<BLOCKQUOTE>
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Ursprüngliche Nachricht-----<BR><B>Von:</B> Paul E. Jones
[mailto:paulej@PACKETIZER.COM]<BR><B>Gesendet:</B> Montag, 3. März 2003
03:21<BR><B>An:</B> ITU-SG16@echo.jf.INTEL.COM<BR><B>Betreff:</B> T.38
potentially broken by recent Corrigendum<BR><BR></FONT></DIV>
<DIV><FONT face=Arial>
<DIV><FONT face=Arial>Folks,</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>I just recently discovered that the ITU-T published
a corrigendum to T.38 (1998) that apparently breaks backward compatibility
for all T.38 devices currently deployed that follow the original 1998
specifications. The particular document in question is Corrigendum
1, which was approved in 2000 and subsequently published in May
2001. You can download the corrigendum document for free from this
site:</FONT></DIV><FONT face=Arial><A
href="http://www.itu.int/rec/recommendation.asp?type=folders&lang=e&parent=T-REC-T.38">http://www.itu.int/rec/recommendation.asp?type=folders&lang=e&parent=T-REC-T.38</A></FONT>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>The issue at hand is a change in the ASN.1 syntax
found in Annex A/T.38. The particular data structure is shown
here:</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV>Data-Field ::= SEQUENCE OF SEQUENCE<BR>{<BR>
field-type ENUMERATED<BR> {<BR> hdlc-data,<BR> hdlc-sig-end,<BR> hdlc-fcs-OK,<BR> hdlc-fcs-BAD,<BR> hdlc-fcs-OK-sig-end,<BR> hdlc-fcs-BAD-sig-end,<BR> t4-non-ecm-data,<BR> t4-non-ecm-sig-end<U><FONT
color=#ff0000>,</FONT></U><BR> <U><FONT
color=#ff0000>...</FONT></U><BR> },<BR> field-data OCTET
STRING (SIZE(1..65535)) OPTIONAL<BR>}</DIV>
<DIV><FONT face=Arial></FONT> </DIV></BLOCKQUOTE>
<DIV dir=ltr><FONT face=Arial>The syntactical change was the addition of
an ellipsis at the end of the ENUMERATED "field-type". In the
published 1998 specification, this ellipsis did not exist.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial>What I would like to know is whether this
change impacts your product or not. I am aware of many deployed
devices on the market today that employs the 1998 syntax without this
ellipsis. I would like to find out to what extent this change is
going to present problems for companies
represented on various lists and, if I get sufficient support, I
want to take a contribution to the ITU-T SG16 meeting in May to try to
resolve this problem in such a way as to not break backward compatibility
and interoperability.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial>I am looking forward to your
replies.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial>Kindest Regards,</FONT></DIV>
<DIV dir=ltr><FONT face=Arial>Paul E.
Jones</FONT></DIV></FONT></DIV>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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