RE: [Rfid] XML vs. Text vs. Binary

["Scott Barvick" <[e-mail]>]

Howard,

I keep pointing to the proposed charter from the BoF, the subsequent update, and the early SLRRP drafts as the set of motivations and goals for the effort.  That is what was published and used to establish the initial interest, and, based on advice from experienced IETFers, frame a scope for a WG that could provide an initial standard development success in an area that needs a standard.

Questions continue about the existence of goals and requirements.  Are there specific things in the proposed charter that need to be discussed?  If so we should do that.  Or, are we looking to answer a question such as the XML vs. binary question by pointing to a line that is or is not yet in the charter?  

Scott


-----Original Message-----
From: [e-mail] on behalf of Howard Kapustein
Sent: Wed 8/3/2005 12:37 AM
To: [e-mail]
Subject: RE: [Rfid] XML vs. Text vs. Binary
 
>The base goals to date have been to focus on
>a single representation that would have the widest applicability so
that
The hard part is defining 'one' syntax which is widely acceptable.
On good days it seems eminently reasonable and do-able.
On others...one wonders how hard herding cats really is...

>a standard could be developed and deployed as quickly as possible.
Admirable goal.
Of course, this has to balance against the other targets - how'd that
go? Fast, Small, Cheap, Quality, Durability, Quick to do, Easy to use --
which are more (or less) important, and to what degree?


Are the goals, constraints and assumptions underlying the solution
called SLRRP clearly documented? Where? This seems to be a critical
linchpin for many of these differences of opinion -- some are
subjective, but lacking a clearly and commonly understood set of
requirements seems to be at the heart of many of these discussions. XML
vs. Binary (among other things) can be argued ad nauseum to no end, and
everyone is right *and* wrong. But given a clearly documented set of
requirements, people may disagree over priorities of the facts, but the
facts remain.

Wouldn't solve all these debates, but would bring a measure of rational
and objective measurement.

	- Howard
 


-----Original Message-----
From: [e-mail] [mailto:[e-mail]]
On Behalf Of Scott Barvick
Sent: Tuesday, August 02, 2005 5:25 PM
To: [e-mail]
Cc: [e-mail]; [e-mail]
Subject: RE: [Rfid] XML vs. Text vs. Binary

Rob and Bud raise a topic that has not yet been fully addressed in the
midst of this discussion - the notion of multiple representations of the
protocol.   

This is even different from the carrying the PDUs over multiple
transports (e.g. TCP, serial, ethernet).  As raised in a previous
thread, the concept of supporting transport of SLRRP PDUs over a non-TCP
(serial) transport, while not currently in the initial SLRRP scope, does
not seem to pose a significant burden in terms of specifying,
implementing, or testing.  All of the differences are isolated in the
transport, and the same core protocol code is executed regardless of how
you transport the PDUs to a particular peer.   

However, the idea of specifying different encodings (profiles),
particularly in the case of human readable vs. binary is something that
I feel would not result in an efficient standard nor an efficient
standard development experience.  You end up with not a single protocol,
but as many protocols as you have representations, and the only thing
common about them may be an initial capabilities exchange.  Each
representation then needs the full round of functional, system, and
interoperability testing that would go with any new protocol.  Of
course, interoperability in this sense means only between
implementations of the same encoding, not implicitly for the all
encodings of the protocol.  The base goals to date have been to focus on
a single representation that would have the widest applicability so that
a standard could be developed and deployed as quickly as possible. 

My thoughts only, of course.  I'm sure there are others out there.

Scott  


On Tue, 2005-08-02 at 15:50, Bud Biswas wrote:
> I see the usefullness of both XML and binary to different vendors.
> Altho' it is true that programmers will generally prefer binary to
> work with, XML is also useful to a different user community (non
> programmers). My preference would be to see that Readers support
> binary as mandatory and XML as optional along with the Middleware
> supports binary as input from reader (mandatory) and XML input as
> optional. This will allow us to build both "thin" readers as well as
> "heavy duty" readers where the readers support XML also and may
> include the middleware software.
>  
> Bud Biswas
> 
> [e-mail] wrote:
>         Viewpoint from another hardware vendor: 
>         
>         If SLRRP gains traction we'll probably want to adapt it to a
>         reader module
>         with a serial interface to maintain a common interface between
>         readers.
>         However, if SLRRP is XML-based I don't think it will be viable
>         for serial
>         I/O. A minimal text protocol is marginal over serial. Adding
>         XML (even if
>         minimal) pushes the bandwidth over the top.
>         
>         I agree with the human readable arguments of text vs binary.
>         With text
>         we've experienced lower training and support costs, faster
>         time-to-market,
>         etc. However, I foresee RFID development becoming more
>         specialized with the
>         proliferation of readers in the supply chain. It's likely that
>         vertical
>         application developers will only concern themselves with a
>         high-level
>         ALE-like interface. RFID middleware developers will grapple
>         with the
>         low-level interfaces. We have a! group of network programmers
>         that tell me
>         they prefer a binary interface. They have tools (LAN
>         analyzers, etc.) to
>         work with binary so they're not concerned with human readable.
>         They argue
>         that programming to a binary interface is easier/higher
>         performance than
>         parsing text.
>         
>         Rob Buck
>         RFID Software Architect
>         Intermec Technologies, Corp.
>         Ofc: 641-472-3082
>         Cell: 319-573-5294
>         
>         -----Original Message-----
>         From: [e-mail]
>         [mailto:[e-mail]] On
>         Behalf Of Margaret Wasserman
>         Sent: Saturday, July 23, 2005 8:15 AM
>         To: Marshall Rose
>         Cc: [e-mail]
>         Subject: Re: [Rfid] XML vs. Text vs. Binary
>         
>         
>         Hi Marshall,
>         
>         I think we are mostly in agreement about the technical
>         trade-offs, 
>         but for some reason that doesn't lead us to the same
>         conclusion...
>         
>         At 9:16 AM +0530 7/23/05, Marshall Rose wrote:
>         >this brings us back full circle: as soon as you have any
>         level of 
>         >nesting, human! type-in becomes problematic. as soon as you
>         decide 
>         >that human type-in isn't mandatory, it is trivial to include
>         a 
>         >standard library to do the heavy lifting while the humans
>         invoke the 
>         >tool using textual commands.
>         
>         Yes, if there is any significant nesting, I agree that a human
>         will 
>         not be able to type the commands in from memory and/or by
>         glancing at 
>         a reference sheet. However, I don't see any reason why this
>         protocol 
>         would require significant nesting, at least for the types of
>         commands 
>         that a human is likely to use directly.
>         
>         With a text encoding, a human could also have certain prepared
>         commands and be able to cut and paste them into the interface
>         -- a 
>         command to reset autonomous operation, for example, or to set
>         a 
>         reader to its default state. Or they could write simple
>         scripts that 
>         would send specific commands or command sequences.
>         
>         >in other words, from where i sit, XML, cXML, etc., enjoy all
>         the 
>         >drawbacks of both purist approaches.
>         
>         Correct, from a "human typing" standpoint, XML, cXML and a 
>         specialized text encoding are all roughly equivalent. However,
>         in my 
>         opinion, they are all much better than a binary encoding.
>         
>         There are two factors involved here, and all three of these
>         choices 
>         (XML, binary or specialized encodings) are fundamentally
>         different 
>         WRT these factors:
>         
>         (1) Can the incoming stream be parsed by a widely available
>         parser, 
>         or is a specialized parser necessary. XML parsers are
>         available for 
>         all likely client systems, but a specialized text encoding or
>         a 
>         binary encoding would require a specialized parser. BTW,
>         subsetting 
>         XML _does not_ require a specialized parser. Reader vendors
>         might 
>         want to includes a specialized (smaller or faster) parser and
>         simply 
>         reject XML constructs that are not included in the subset, but
>         clients could use a regular XML parser for this purpose.
>         
>         (2) Can ! text processing tools be used to send control
>         messages and 
>         interpret the responses, or would binary processing be
>         required. 
>         Both XML and a specialized text encoding would allow text
>         processing 
>         of the messages and results, while a binary encoding would
>         require 
>         binary processing.
>         
>         You've indicated that it is possible, with a binary encoding,
>         for 
>         clients to run a tool that gives them text-based access.
>         That's 
>         true, but users would need to _get_ that tool from
>         somewhere... So, 
>         we are back to requiring specialized code on the client side
>         to 
>         access this protocol.
>         
>         This isn't a religious issue with me -- I've just learned the 
>         benefits of text-based encoding the hard way, and I don't want
>         to 
>         deal with another binary protocol... So, for the moment, we
>         may have 
>         to just agree to disagree. We'd obviously need to resolve this
>         before we can move ahead, though.
>         
>         Only a few of us have expressed any opinion on this subject.
>         Are there others out there that have an opinion? There are two
>         questions 
>         that I'd especially like to hear answered by specific other
>         people on 
>         this list:
>         
>         (1) I'd like to hear from other reader vendors about whether
>         they 
>         think that XML would place a prohibitive burden on their
>         readers. It 
>         has been asserted that XML would have prohibitive system
>         requirements 
>         for the reader. That certainly isn't true of ThingMagic's
>         networked 
>         readers. In fact, using a standard parser, like XML, would
>         reduce 
>         our development (especially debugging) and testing costs 
>         substantially, and would make it more likely that we would
>         implement 
>         this protocol.
>         
>         (2) It would be very interesting to know if RFID users would
>         see any 
>         benefit to a text-based encoding. Are there folks on this list
>         who 
>         have RFID installed in real-world or even pilot installations
>         (not 
>         just a few units in a test lab)? Do you have any opinions
>         about 
>         whether the ability to access t! he reader using text-based
>         tools from 
>         a client system that doesn't have a specialized client (or
>         library) 
>         installed would be useful? Or do you see this as having
>         little/no 
>         value?
>         
>         Margaret
>         
>         
>         
>         
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