RE: [Speechsc] message-length clarification

["Reifenrath, Klaus, VF-Group" <[e-mail]>]

I am very much in favor to remove the message length from the startline, because it is not very useful. 
 
For a similar discussion (that took place quite some time ago!) please see http://www1.ietf.org/mail-archive/web/speechsc/current/msg00690.html.
If we change the startline please let us revisit this as well!
 
Regards,
Klaus


________________________________

	From: Baggia Paolo [mailto:[e-mail]] 
	Sent: Mittwoch, 19. April 2006 16:36
	To: Carter, Jerry; [e-mail]
	Cc: Bergallo Patrizio
	Subject: R: [Speechsc] message-length clarification
	
	
	 
	Jerry,
	
	with reference to Eric Burger's e-mail
	"[Speechsc] Finishing in Our Lifetime", in our opinion,
	this issue is not a Priority 1 or Priority 2 one.
	
	Our preference is to be conservative as much as is 
	possible, so we prefer to leave the current behaviour. 
	We can live with #2 (zero-padding).
	
	The worst is #1 "remove message-length".
	
	Paolo&Patrizio
	
	-----Messaggio originale-----
	Da: Carter, Jerry [mailto:[e-mail]] 
	Inviato: mercoledì 19 aprile 2006 16.20
	A: [e-mail]
	Oggetto: RE: [Speechsc] message-length clarification
	
	I believe that Dave Burke's order correctly captures the discussion. There
	was a preference for removing the message-length entirely.
	
	> -----Original Message-----
	> From: Burger, Eric [mailto:[e-mail]]
	> Sent: Tuesday, April 18, 2006 5:52 PM
	> To: Dave Burke; Corby Anderson; Brett Gavagni
	> Cc: [e-mail]; Shanmugham, Saravanan; Bergallo Patrizio
	> Subject: RE: [Speechsc] message-length clarification
	> 
	> Any takers? I'm with option 2, as that leaves things as it and is
	> workable.
	> 
	> -----Original Message-----
	> From: Dave Burke [mailto:[e-mail]]
	> Sent: Monday, April 17, 2006 12:57 PM
	> To: Corby Anderson; Brett Gavagni
	> Cc: [e-mail]; Shanmugham, Saravanan; Bergallo Patrizio
	> Subject: Re: [Speechsc] message-length clarification
	> 
	> In the interests of rough consensus:
	> 
	> o Preference for:
	> - Remove message-length altogether
	> 
	> o Can live with:
	> - Zero-padding note (as per Sarvi's suggestion)
	> 
	> o Don't like:
	> - message-length doesn't include start-line
	> (because this is a half-way house with negligible value - the
	> parser will be searching for \n anyways so why not iterate up
	> to Content-Length)
	> 
	> Dave
	> 
	> ----- Original Message -----
	> From: "Brett Gavagni" 
	> To: "Corby Anderson" 
	> Cc: ; "Shanmugham, Saravanan" ;
	> "Bergallo Patrizio" 
	> Sent: Monday, April 17, 2006 3:42 PM
	> Subject: Re: [Speechsc] message-length clarification
	> 
	> 
	> > That was the original suggestion when I started with this thread
	> >
	> (http://www1.ietf.org/mail-archive/web/speechsc/current/msg01722.html),
	> > and this suggestion wasn't too well received.
	> >
	> > "Propose to modify the wording that message-length does NOT include
	> the
	> > start-line as an issue to track for the next draft."
	> >
	> > So then we diverged into the defining the true value of the
	> message-length
	> > token, and thus the proposal for the removal of the message-length
	> token
	> > in its entirety.
	> >
	> > This removal proposal was fueled even more with the distinction that
	> the
	> > MRCPv2 session control is separated, especially since MRCPv2 messages
	> are
	> > NOT expected/described as tunnelled.
	> >
	> > I'd be happy if the message-length was modified as originally proposed
	> to
	> > NOT include the size of the start-line in the length, or if the
	> > message-length to be removed from the draft.
	> >
	> > IMO, anything else is a hack. =)
	> >
	> > Continue the flame roasting as necessary. =)
	> >
	> > Thanks,
	> >
	> > Brett Gavagni
	> > WebSphere Voice Server Development
	> > http://www-306.ibm.com/software/pervasive/voice_server/
	> > [e-mail]
	> >
	> >
	> >
	> >
	> > Corby Anderson 
	> > 04/14/2006 08:26 PM
	> >
	> > To
	> > Brett Gavagni/West Palm Beach/IBM@IBMUS
	> > cc
	> > "Shanmugham, Saravanan" , [e-mail], Bergallo
	> > Patrizio 
	> > Subject
	> > Re: [Speechsc] message-length clarification
	> >
	> >
	> >
	> >
	> >
	> >
	> > No, you're not the only one. :-) It is hacky. The size calculation
	> that
	> > Dave Burke posted is concise, but it's cumbersome.
	> >
	> > But stepping back a little, it *is* helpful to know the size ahead of
	> > time. Since clients can share an MRCP control channel, it's makes the
	> > server's job easier if it knows ahead of time how many bytes will be
	> in a
	> > particular command. You can imagine an implementation where a the
	> socket
	> > reader understands the first-line format enough to read all the bytes
	> for
	> > a single message into a buffer and then hand it off to a different
	> > class/function/thread for further processing.
	> >
	> > How about if the length pertained to the size of everything *except*
	> the
	> > first line? That would make the size calculation trivial and would
	> still
	> > offer the benefit of having the size around for parsing purposes.
	> >
	> > Corby Anderson
	> > Tellme Networks
	> >
	> > Brett Gavagni wrote:
	> > Am I the only one that thinks this suggestion for padding a fixed
	> length
	> > is a Band-Aid (*hack) for the real problem identified by this thread?
	> >
	> > Thanks,
	> >
	> > Brett Gavagni
	> > WebSphere Voice Server Development
	> > http://www-306.ibm.com/software/pervasive/voice_server/
	> > [e-mail]
	> >
	> >
	> >
	> >
	> > "Shanmugham, Saravanan" 
	> > 04/14/2006 02:06 PM
	> >
	> > To
	> > "Bergallo Patrizio" ,
	> 
	> > cc
	> >
	> > Subject
	> > RE: [Speechsc] message-length clarification
	> >
	> >
	> >
	> >
	> >
	> >
	> > Pete/Bergallo,
	> >
	> > Leading spaces are illegal per the current ABNF definition.
	> > But Pete's suggestion is perfectly legal and makes the encoding phase
	> just
	> >
	> > as effciient.
	> >
	> > I can add this clarification/suggestion for implementers into the
	> > specification.
	> >
	> > Thx,
	> >
	> > Sarvi
	> >
	> > From: Bergallo Patrizio [mailto:[e-mail]]
	> > Sent: Friday, April 14, 2006 1:44 AM
	> > To: [e-mail]
	> > Subject: RE: [Speechsc] message-length clarification
	> >
	> >
	> > I agree that problems arise more on encoding side than in decoding
	> one.
	> > What about using leading SP, with the same purpose of leading zeros
	> > mentioned by Pete?
	> > Is it legal?
	> > Anyway, though I'm not a big fan of message-length field, I think that
	> > removing it at this stage of spec should be avoided.
	> >
	> > Regards,
	> > Patrizio Bergallo, Loquendo.
	> >
	> >
	> > -----Original Message-----
	> > From: Pete Cordell [mailto:[e-mail]]
	> > Sent: Friday, April 14, 2006 9:55 AM
	> > To: Dave Burke
	> > Cc: [e-mail]
	> > Subject: Re: [Speechsc] message-length clarification
	> >
	> >
	> > As someone watching from the sidelines, this issue about the
	> > representation
	> > of the length field potentially changing the value of the
	> > length that needed
	> > to be encoded occurred to me also.
	> >
	> > I wondered if you could use leading zeros in the length field
	> > so that it is
	> > always fixed length. e.g. in C it would be something like:
	> >
	> > sprintf( lstr, "%04d", len ); // Not sure if 4 is the right number!
	> >
	> > Messages would then look like:
	> >
	> > MRCP/2.0 0047 543256 200 COMPLETE
	> > ...
	> >
	> > Still a bit of a gotcha though, that could lead to one of
	> > those one in a
	> > hundred type bugs!
	> >
	> > Regards,
	> >
	> > Pete.
	> > --
	> > =============================================
	> > Pete Cordell
	> > Tech-Know-Ware Ltd
	> > for XML to C++ data binding visit
	> > http://www.tech-know-ware.com/lmx
	> > (or http://www.xml2cpp.com)
	> > =============================================
	> >
	> > ----- Original Message -----
	> > From: "Dave Burke"
	> > To: "Shanmugham, Saravanan" ; "Brett Gavagni"
	> >
	> > Cc:
	> > Sent: Friday, April 14, 2006 12:39 AM
	> > Subject: Re: [Speechsc] message-length clarification
	> >
	> >
	> >
	> > Just wanted to insert one point that I haven't seen mentioned: The
	> > message-length makes it easier to decode but not encode.
	> >
	> > This is because the message-length also includes the number
	> >
	> > of bytes
	> >
	> > that
	> > specify the message-length in the header. The algorithm for
	> >
	> > determining
	> >
	> > the message-length has to add up all the bytes in the
	> >
	> > message to get a
	> >
	> > total (label: N), then determine the number of bytes to represent N
	> > (label: M), then check if the total N+M rolls over a power
	> >
	> > of 10 (if it
	> >
	> > does you need another byte). The value to insert for the
	> >
	> > message-length is
	> >
	> > not simply N+M but rather
	> >
	> > (N >= (10^M-M)) ? N+M+1 : N+M
	> >
	> > For example, if N=97 then M=2 and N+M=99=message-length.
	> >
	> > However, if
	> >
	> > N=98
	> > then M=2 but now N+M=100 => message-length=N+M+1
	> >
	> > Sorta awkward - no?
	> >
	> > Dave
	> >
	> >
	> >
	> >
	> >
	> > ----- Original Message -----
	> > From: "Brett Gavagni"
	> > To: "Shanmugham, Saravanan"
	> > Cc:
	> > Sent: Thursday, April 13, 2006 1:52 PM
	> > Subject: RE: [Speechsc] message-length clarification
	> >
	> >
	> > Hi Sarvi,
	> >
	> > I realize that it may be late in the game for addressing
	> >
	> > problems in
	> >
	> > the specification, but I would evangelize that its cheaper
	> >
	> > to pay now
	> >
	> > (potential standardization delays) than to pay later (poor
	> >
	> > adoption)
	> >
	> > due to convolution and problematic issues in the spec.
	> >
	> > Since the session control for MRCPv2 is separated (a la SIP, RTSP,
	> > etc..) and not tunnelled, what would be the compelling
	> >
	> > reason that the
	> >
	> > message-length token exist in the start-line especially since the
	> > "Content-Length" header?
	> >
	> > I'm now proposing the removal of the message-length token from the
	> > start-line in entirety, as it is at least redundant and
	> >
	> > deviating from
	> >
	> > the HTTP-like conventions leveraged throughout the spec.
	> >
	> > Thanks,
	> >
	> > Brett Gavagni
	> > WebSphere Voice Server Development
	> > http://www-306.ibm.com/software/pervasive/voice_server/
	> > [e-mail]
	> >
	> >
	> > ...cut...
	> >
	> >
	> >
	> > _______________________________________________
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	> > [e-mail] https://www1.ietf.org/mailman/listinfo/speechsc
	> >
	> >
	> >
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	> S.p.A.
	> >
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