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<DIV><FONT face=Arial size=2>Francois, Paul, et al,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Well, there were some changes, but publicly
discussed here-- not strictly my editorial changes :-). Essentially, the
same functionality is achieved as described in TD-26a, but with a new field
"earlyH245Control" in the Setup message, rather than the "h245Control" in the
H323-UU-PDU.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The procedure has been dubbed "Early H.245" and is
described in section 8.2.3/H.323v4.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Paul</FONT></DIV>
<BLOCKQUOTE dir=ltr
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=audet@NORTELNETWORKS.COM
href="mailto:audet@NORTELNETWORKS.COM">Francois Audet</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=ITU-SG16@mailbag.cps.intel.com
href="mailto:ITU-SG16@mailbag.cps.intel.com">ITU-SG16@mailbag.cps.intel.com</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, July 26, 2000 1:52
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Expediting H.245</DIV>
<DIV><BR></DIV>
<P><FONT size=2>Actually, I believe the editor (correct me if I'm wrong Paul
Jones) did some </FONT><BR><FONT size=2>editorial (I love this word) changes
from what was in TD-26a. So Paul Long should </FONT><BR><FONT size=2>really
look at the latest and greatest H.323v4.</FONT> </P>
<P><FONT size=2>> -----Original Message-----</FONT> <BR><FONT size=2>>
From: Callaghan, Robert [<A
href="mailto:Robert.Callaghan@ICN.SIEMENS.COM">mailto:Robert.Callaghan@ICN.SIEMENS.COM</A>]</FONT>
<BR><FONT size=2>> Sent: Wednesday, July 26, 2000 8:28 AM</FONT> <BR><FONT
size=2>> To: <A
href="mailto:ITU-SG16@MAILBAG.INTEL.COM">ITU-SG16@MAILBAG.INTEL.COM</A></FONT>
<BR><FONT size=2>> Subject: Re: Expediting H.245</FONT> <BR><FONT
size=2>> </FONT><BR><FONT size=2>> </FONT><BR><FONT size=2>>
Paul,</FONT> <BR><FONT size=2>> </FONT><BR><FONT size=2>> This topic was
discussed in the Osaka meeting. The need for a faster</FONT> <BR><FONT
size=2>> started H.245 was very apparent for several reasons. The
compromised</FONT> <BR><FONT size=2>> proposal is presented in TD-26a from
Osaka. It is the same </FONT><BR><FONT size=2>> as your
proposal</FONT> <BR><FONT size=2>> in the number of required
messages. It also solves the problems of</FONT> <BR><FONT size=2>>
negotiating particular elements by including full TCS and M/S in the</FONT>
<BR><FONT size=2>> procedure.</FONT> <BR><FONT size=2>> </FONT><BR><FONT
size=2>> Please look at this.</FONT> <BR><FONT size=2>> </FONT><BR><FONT
size=2>> Bob</FONT> <BR><FONT size=2>> </FONT><BR><FONT size=2>>
------------------------------------------------------------------</FONT>
<BR><FONT size=2>> Robert Callaghan</FONT> <BR><FONT size=2>> Siemens
Enterprise Networks</FONT> <BR><FONT size=2>> Tel:
+1.561.923.1756 Fax: +1.561.923.1403</FONT> <BR><FONT
size=2>> Email: Robert.Callaghan@ICN.Siemens.com</FONT> <BR><FONT
size=2>>
------------------------------------------------------------------</FONT>
<BR><FONT size=2>> </FONT><BR><FONT size=2>> -----Original
Message-----</FONT> <BR><FONT size=2>> From: Paul Long [<A
href="mailto:Plong@SMITHMICRO.COM">mailto:Plong@SMITHMICRO.COM</A>]</FONT>
<BR><FONT size=2>> Sent: Wednesday, July 26, 2000 11:00
AM</FONT> <BR><FONT size=2>> To:
ITU-SG16@mailbag.cps.intel.com</FONT> <BR><FONT size=2>>
Subject: Expediting H.245</FONT>
<BR><FONT size=2>> </FONT><BR><FONT size=2>> Here is a proposal for
"expediting" H.245--eliminating explicit</FONT> <BR><FONT size=2>>
establishment of the H.245 control channel, H.323 Phase B. </FONT><BR><FONT
size=2>> But first, here</FONT> <BR><FONT size=2>> are the reasons for
doing so:</FONT> <BR><FONT size=2>> </FONT><BR><FONT size=2>> - At
SuperOp! some people incorrectly assumed that an EP is </FONT><BR><FONT
size=2>> not required to</FONT> <BR><FONT size=2>> support H.245 if Fast
Connect is performed. However wrong </FONT><BR><FONT size=2>> they may be,
we</FONT> <BR><FONT size=2>> all probably believe to some degree that this
would be a </FONT><BR><FONT size=2>> natural thing to</FONT> <BR><FONT
size=2>> do.</FONT> <BR><FONT size=2>> - A much-respected colleague at
another company said that </FONT><BR><FONT size=2>> H.245 is a major</FONT>
<BR><FONT size=2>> encumbrance for large-scale entities.</FONT> <BR><FONT
size=2>> - Some vendors have expressed a desire to use H.245 features,
</FONT><BR><FONT size=2>> e.g., DTMF and</FONT> <BR><FONT size=2>>
third-party pause, without first having to initiate H.245 </FONT><BR><FONT
size=2>> procedures, i.e.,</FONT> <BR><FONT size=2>> TermCap exchange
and MSD.</FONT> <BR><FONT size=2>> - I have heard that SIP-H.323
interworking may eliminate </FONT><BR><FONT size=2>> H.245. This may</FONT>
<BR><FONT size=2>> primarily be due to the message-intensive channel
establishment phase.</FONT> <BR><FONT size=2>> </FONT><BR><FONT size=2>>
In order to tempt you into actually reading all of the following</FONT>
<BR><FONT size=2>> explanation, here's the end result. The minimal dialogue
necessary to</FONT> <BR><FONT size=2>> establish a call and the H.245
session in both directions:</FONT> <BR><FONT size=2>> </FONT><BR><FONT
size=2>> Setup(expedite)
--></FONT> <BR><FONT
size=2>> <--
Connect(expedite)</FONT> <BR><FONT size=2>> </FONT><BR><FONT size=2>>
Here's how it can be done. Add the following ASN.1 component </FONT><BR><FONT
size=2>> to Setup and</FONT> <BR><FONT size=2>> all of the possible
responses, i.e., Alerting, </FONT><BR><FONT size=2>> CallProceeding,
Connect,</FONT> <BR><FONT size=2>> Facility, and Progress:</FONT> <BR><FONT
size=2>> expedite
ExpediteH245Tunneling OPTIONAL</FONT> <BR><FONT size=2>> </FONT><BR><FONT
size=2>> Define this new type:</FONT> <BR><FONT
size=2>> ExpediteH245Tunneling
SEQUENCE</FONT> <BR><FONT size=2>> {</FONT>
<BR><FONT size=2>>
...</FONT> <BR><FONT size=2>> }</FONT> <BR><FONT
size=2>> </FONT><BR><FONT size=2>> For Setup, the presence of expedite
_requests_ an expedited </FONT><BR><FONT size=2>> H.245 session;</FONT>
<BR><FONT size=2>> for all the other messages, this _grants_ the request.
An EP </FONT><BR><FONT size=2>> shall only</FONT> <BR><FONT size=2>>
encode expedite if it also sets h245Tunneling to TRUE in the </FONT><BR><FONT
size=2>> same message.</FONT> <BR><FONT size=2>> An expedited H.245
session causes both EPs to treat the H.245 </FONT><BR><FONT size=2>>
session _as</FONT> <BR><FONT size=2>> if_ they had already successfully
performed the TermCap </FONT><BR><FONT size=2>> exchange and MSD</FONT>
<BR><FONT size=2>> before the calling EP transmitted Setup. Once the called
EP grants the</FONT> <BR><FONT size=2>> request, the H.245 state in both
EPs is the same as if the TCSs had</FONT> <BR><FONT size=2>> contained no
OPTIONAL components, the protocolIdentifiers </FONT><BR><FONT size=2>> were
set to the</FONT> <BR><FONT size=2>> lowest version of H.245 specified by
H.323 based on the </FONT><BR><FONT size=2>> H.225.0 version, and</FONT>
<BR><FONT size=2>> the result of the MSD is that the calling EP is MASTER
[could </FONT><BR><FONT size=2>> use any other</FONT> <BR><FONT size=2>>
method for MSD, including the EP with the "greater" IP address is the</FONT>
<BR><FONT size=2>> MASTER].</FONT> <BR><FONT size=2>> </FONT><BR><FONT
size=2>> If the called EP accepts at least one Fast Connect channel, all of
the</FONT> <BR><FONT size=2>> accepted channels are inherited as
capabilities by both EPs </FONT><BR><FONT size=2>> as if they had</FONT>
<BR><FONT size=2>> successfully performed a second TermCap exchange before
the called EP</FONT> <BR><FONT size=2>> responded to Setup. Once the called
EP accepts the Fast </FONT><BR><FONT size=2>> Connect channel(s),</FONT>
<BR><FONT size=2>> the H.245 state in both EPs is the same as if the TCSs
had contained</FONT> <BR><FONT size=2>> capabilityTables with entries for
all Fast Connect OLCs, </FONT><BR><FONT size=2>> numbered starting</FONT>
<BR><FONT size=2>> with 0, and single capabilityDescriptors components with
a single</FONT> <BR><FONT size=2>> capabilityDescriptor, numbered 0,
containing a simultaneous </FONT><BR><FONT size=2>> capability for</FONT>
<BR><FONT size=2>> each unique sessionID value and an alternative
capability for </FONT><BR><FONT size=2>> each OLC.</FONT> <BR><FONT
size=2>> </FONT><BR><FONT size=2>> In accordance with procedures already
defined in H.245 and </FONT><BR><FONT size=2>> H.323, the EPs</FONT>
<BR><FONT size=2>> may subsequently perform the TermCap exchange and MSD at
any </FONT><BR><FONT size=2>> time and any</FONT> <BR><FONT size=2>>
number of times to update the state of H.245 in the </FONT><BR><FONT
size=2>> respective EPs. For</FONT> <BR><FONT size=2>> example, the
called EP can initiate the TermCap exchange </FONT><BR><FONT size=2>>
"again" immediately</FONT> <BR><FONT size=2>> upon receiving Setup (e.g.,
in Alerting) to indicate advanced </FONT><BR><FONT size=2>> DTMF caps,
and</FONT> <BR><FONT size=2>> the calling EP can start exploiting those
caps in the very </FONT><BR><FONT size=2>> same message it</FONT> <BR><FONT
size=2>> returns the TCSAck.</FONT> <BR><FONT size=2>> </FONT><BR><FONT
size=2>> Setup(expedite) --></FONT> <BR><FONT size=2>> <--
Alerting(expedite, TCS w/UserInputCap=dtmf)</FONT> <BR><FONT size=2>>
Facility(TCSAck+Signal="7#0") --></FONT> <BR><FONT size=2>>
</FONT><BR><FONT size=2>> Benefits:</FONT> <BR><FONT size=2>> 1. Very
little additional signaling is required (only a new </FONT><BR><FONT
size=2>> codepoint)--this</FONT> <BR><FONT size=2>> feature is mostly
new interpretation of existing signaling.</FONT> <BR><FONT size=2>> 2. The
backwards-compatibility problems associated with </FONT><BR><FONT size=2>>
allowing fastStart</FONT> <BR><FONT size=2>> and h245Control in Setup are
avoided.</FONT> <BR><FONT size=2>> 3. The H.245 session is available to the
calling EP in 1 RTD </FONT><BR><FONT size=2>> and to the</FONT> <BR><FONT
size=2>> called EP in 0.5 RTDs--the same as media and Fast Connect!</FONT>
<BR><FONT size=2>> 4. Without using Fast Connect, the calling EP can start
</FONT><BR><FONT size=2>> transmitting media</FONT> <BR><FONT size=2>>
in one less RTD than it could without this new feature. Here are the</FONT>
<BR><FONT size=2>> comparisons:</FONT> <BR><FONT
size=2>> (Feature:
calling EP RTDs, called EP RTDs)</FONT> <BR><FONT
size=2>> Fast Connect w/ or
w/o Expedite: 1, 0.5</FONT> <BR><FONT
size=2>> Expedite w/o Fast
Connect: 2, 2.5</FONT> <BR><FONT
size=2>> Neither: 3,
2.5</FONT> <BR><FONT size=2>> 5. Perhaps this feature could benefit
SIP-H.323 interworking </FONT><BR><FONT size=2>> if H.245 with</FONT>
<BR><FONT size=2>> full TCS and MSD is deemed too onerous, i.e., don't
allow </FONT><BR><FONT size=2>> "real" TCSs and</FONT> <BR><FONT
size=2>> MSDs.</FONT> <BR><FONT size=2>> 6. Marginally less bandwidth
consumption and quicker </FONT><BR><FONT size=2>> transmission of
initial</FONT> <BR><FONT size=2>> call-signaling messages (okay, I'm
reaching... :-) ).</FONT> <BR><FONT size=2>> 7. This opens up other
possibilities (maybe that's a </FONT><BR><FONT size=2>> disadvantage :-)
).</FONT> <BR><FONT size=2>> That's why I defined H245TunnelingExpedition
to be </FONT><BR><FONT size=2>> extensible. For example,</FONT> <BR><FONT
size=2>> we could indicate that all TCS and MSD requests will be
</FONT><BR><FONT size=2>> rejected, so don't</FONT> <BR><FONT size=2>>
bother.</FONT> <BR><FONT size=2>> 8. Works well with others. :-) I mean
that it naturally fits </FONT><BR><FONT size=2>> in with Fast</FONT>
<BR><FONT size=2>> Connect and H.245 Tunneling.</FONT> <BR><FONT
size=2>> 9. Easy to understand. Okay, to me at least.</FONT> <BR><FONT
size=2>> </FONT><BR><FONT size=2>> This is not and may never be a formal
contribution. Perhaps </FONT><BR><FONT size=2>> just consider it</FONT>
<BR><FONT size=2>> as food for thought.</FONT> <BR><FONT size=2>>
</FONT><BR><FONT size=2>> Paul Long</FONT> <BR><FONT size=2>> Smith
Micro Software, Inc.</FONT> <BR><FONT size=2>> </FONT><BR><FONT size=2>>
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