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First XML Protocol Face-To-Face Meeting Minutes
October 11-12, 2000, hosted by IBM inRaleigh, NC, USA. Minutes taken byHugo HaasandYves Lafon.
Introduction
David Fallside gave administrative details about the IBM site and theagenda of the meeting.
Introductions
- Yves Lafon: W3C Team Contact
- Hugo Haas: W3C Team Contact (Alternate)
- Jeffrey Kay: Engenia Software
- Ed Mooney: Sun Microsystems
- Alex Milowski: Lexica
- Jim Trezzo: Oracle
- John Evdemon: XMLSolutions
- Volker Wiechers: SAP AG
- Richard Martin: Active Data Exchange
- Bill Anderson: Xerox
- Henry Lowe: OMG
- John Ibbotson: IBM
- Mark Needleman: Data Research Associates
- Waqar Sadiq: Vitria Technology
- Amr Yassin: Philips Research (Alternate)
- Henrik Frystyk Nielsen: Microsoft
- Paul Cotton: Microsoft (Alternate)
- David Orchard: Jamcracker
- Noah Mendelsohn: Lotus Development
- Murali Janakiraman: Rogue Wave
- Kevin Mitchell: XMLSolutions (Alternate)
- Randy Waldrop: WebMethods
- Glen Daniels: Allaire
- Simeon Simeonov: Allaire AC Rep
- Fransisco Cubera: IBM (Alternate)
- David Ezell: Hewlett Packard
- Stuart Williams: Hewlett Packard (Alternate)
- Kazunori Iwasa: Fujitsu
- Oisin Hurley: IONA Technologies
- Ray Denenberg: Library of Congress
- Yan Xu: DataChannel
- David Burdett: CommerceOne
- Vilhelm Rosenqvist: NCR
- Alex Ceponkus: Bowstreet
- Mark Nottingham: Akamai (AC Rep)
- Andrew Eisenberg: Progress Software
- Jean-Jacques Moreau: Canon
- Herve Ruellan: Canon
- Conleth O'Connell: Vignette
- Ray Whitmer: Netscape
- Randy Hall: Intel
- Dick Brooks: 8760 (Invited Expert)
- Bjoern Heckel: Epicentric
- David Fallside: IBM (Chair)
What?
We must first produce the requirements for the protocol, within the scopeof the charter of the WG. It will be published as a Note within the comingmonth, and will be evolving. Editors will be (resolved on the second day) AlexMilovski and Henrik Frystyk Nielsen.
The final deliverable is the XML Protocol Specification. We will provide adescription using an XML Schema. In order to garantee interoperabilty, thedocument will go through a Candidate Recommendation.
The Working Group is required to publish a document within every threemonths. The documents will be public. The first publication of a documentrequires W3C Director's approval (allow around 1 week). The plan of ourdeliverables is the following:
- The Requirements Document.
- The specification, going through the following stages:
- Working Draft
- Last Call Working Draft
- Candidate Recommendation
- Proposed Recommendation
- Recommendation
We will keep an issues list and write a glossary to make sure thateverybody uses the same vocabulary to talk about the same things.
How?
Communication
Mailing lists
W3C has decided to make the deliberation more public. Discussions should goto the public (and archived) mailing list xml-dist-app. @@@How manymembers@@@
The member-only list is there for administratrive purposes andcommunication with other WGs which are Member confidential.
Note from Paul Cotton: Watch out when you hit the Reply button to be sureyou send your email to the right place!
Discussions about the requirements will be Member only, so that we canpublish a first version rapidly, and we get feedback from the public on thisfirst publication.
Then discussions will be public.
Teleconference
They will happen on a weekly basis.
The agenda will be posted 2 days in advance on the Member-only list.
Minutes will be published on the public. If you don't want to havesomething publicly published, please notify the chair and there will be aMember-only version and a public one.
A scribe is needed for the teleconference.
The slot proposed is on Wedesday, 8am PST/11am EST/5pm MET. That time maychange.
David Orchard noted that it overlaps the XML Core teleconference, but thereis no way that we can find a time with no conflicts.
Face-To-Face
We are required to have a minimum of 3 face-to-face meetings per year.
We can also go to 1 or 2 public meetings of some sort. Example: XMLSchema's editors went to public conferences.
This working group is very public because a lot of other communities arealready involved in XML protocols/messaging.
The next one will be hosted by Microsoft at Redmond, WA, on December13-14.
We are planning to have two face-to-face meetings next year. The expecteddates are March 2001 and June 2001.
Paul Cotton noted that there is an all-WG meeting during the February 2001meeting. We have to consider if we want to go, and if we want to meet anotherWorking Group there.
Process
Large Group!
We are an unusually large Working Group. We have considered dividing thegroup into subgroups. The work is divided into 4 components:
- Message Envelope
- Transport
- Content for RPC
- Serialization
We have considered dividing the Working Group in 4 smaller groups workingon each of these areas.
In order to make this large group work, we need consistency: signing up inthis WG is a serious commitment and W3C's notion of good standing applies.
Decision making
Decisions are achieved by consensus.
There are different ways to achieve consensus: straw polls, more formalvotes, .... How to deal with disagreement? Anyone has the option of recordingtheir dissent.
The system that we are going to use will be less formal voting: discussionof the topic, used to formulate a number of alternatives, and then use a strawpoll to see with which solution we want to use. If we really can't agree, wewill use a formal vote.
The role of SOAP
We are going to design requirements.
We will then consider whether SOAP 1.1 reasonnably meets the requirements.If yes, we can use this aspect of SOAP. If not, we will design something forthe requirements not met.
We won't consider any new version of SOAP; we will use SOAP 1.1.
- Is there a name for this protocol?
- Yes, it is "XML Protocol".
- Glen Daniels: Seems too generic.
- Paul Cotton: There is already XML Schema, XML Query.
- Yan Xu: Yes, but there are already others XML protocols.
- Paul Cotton: Microsoft also has an XML schema language, and everybody knows what the W3C XML Schema language is.
- David Fallside: if this is a problem, we can add this to the issue list.
- Henrik Frystyk Nielsen: Already an issue list for SOAP.
- Noah Mendelsohn: How do we deal with our charter? Is the charter prescriptive? If it's the case, we should try to swallow our personnal feelings because modifying the charter puts the bar high.
- YL: Criticism about the name from AC comments it is not the same kind of protocols as the IETF has. It was not listed as a critical issue.
- Ray Denenberg: Name of the Working Group doesn't imply the name of the specification produced (not in charter).
- Paul Cotton: That has always been the case within W3C.
When?
Schedule. See David's slides.
- Something useful with the requirements is use cases.
- Paul Cotton: seconded.
Charter
We divided the group into 4 subgroups to each examine one of the componentsin the charter (envelope, RPC, serialization, HTTP transport).
Envelope group (Henrik Frystyk Nielsen)
look at the charter and look at the things addressing envelope.
What is an envelope then look into the charter?
Simple -> nested protocol.
Security issue, how to find a good model for extensibility.
relationship with schema, no overlap with schemas.
HTTP is not the only one transfer protocol.
Simple is a relative term, fuzzy. We need some use cases and then we shouldhave simple cases simple in practise.
Very simple negotiation to decide when to extend things.
intermediaries, can they modify the message or not?
there should be a mechanism to support links. It is possible to have two waysto use binary data, import a blob mechanism or point to an external link (inebXML it is done within the MIME packaging).
Enveloppe should not rely on the underlying transfer.
Regarding application semantics, some spinoff WG should work on that andverify that the envelope is extensible enough.
How to figure out how to talk to another party is description of service andthus out of scope.
I18N concerns and security issues about securing an envelope in anotherenveloppe.
- Q: can we mandate that these documents are in utf8 format or is it possible to carry message in different national encodings?
- A: this should be in the requirement doc.
- Q: link btw the binding and the envelope
- A: if you have a msg path and they have multiple binding, how do they interact all semantic you want to express have to be in the boundaries of the envelope, otherwise it may be lost from one hop to another. protocol binding should be transparent to the envelope, but protocol used is not transparent as the model is different depeding on the transport.
- Q: HTTP model is more a framing protocol that resp/req.
- A: it may break intermediaries if http breaks req/resp model.
- Q: evolvability only applies to encapsulation data not encapsulated one
- A: envelope should provide hooks for application to address evolvability
2nd group: RPC (David Burdett)
RPC is a request-response like protocol a particular format forcommunicating informations such as method names parameters that are typicallymapped to procedure calls into an application.
Define an egreed convention for the wire format- not be constrained by a req/resp approach - layering will help reuse for other environment, like other protocols/message types
- we should decide if we setup competive initiative, collaborate with other initiative, don't do anything and let others do the work.
ex: do you require a priori knowledge or do we have self describing requests
- Q: how you see issue 2 wiht paragraph 2.5?
- A: itmeans out of scope but. 1.2 bullet 2, it should be deployed automatically without central authority. Automatic service discovery lead to this.
- Q: RPC doesn't define a wire format, it is the serialization job.
- A: abstraction is method name and parameters defined in one way. abstraction are higher level than XML
- A: you don't define a wire format there but a way of mapping proc call in RPC.
- A: we're not dealing with smealess binding to a language
- Q: http post fits also the RPC model.
- A: some rpc have some idl bundled to them, you also have exception handling we should focus on our abstract version of how to handle rpc.
3rd Group: serialization (Stuart Williams)
Syntactic/non-syntactic, what does that means? This was the test of commonunderstanding.
We should be capable of serializing syntactic datatypes like what is definedin XML Schemas datatypes.
We preferred to use abstract rather than non-syntactic. THe serializationshould be independant of any language binding, so you don't need to have thesame env on both side. There was a recognition that streamed like transferwere not adressed.
- Q: What is a difference btw a large binary blob and an attachment. We opened the box of security with no time to finish.
- A: diff btw blob and attachement, attachement are a typed link.
- Q: I hope we are not trying to define a subsyntax of XML to express schemas
- A: the natural fit to XML is tree structure, we should tranport arbitrary graph not tree, see RDF.
- Q: replace non-syntactic by abstract, would that make thigs clearer?
- A: this should be fine for me.
- Q: are we inventing a new language?
- A: I don't see that.
We should be more specific in what we mean by non-syntactic.
DF: we will fix that by putting it in the requirement doc or in the glossary.use cases may solve the pb of what we want to send.
4th group: protocol group (David Orchard)
recommandations: abstract datamodel (infoset). the wire protocol is what wesee when we bind to http protocol (for ex). The datamodel can be bounddifferently. In soap it is roughly one to one but if you want to map to otherprotocol you have problems.
Then there should be mapping btw that data model and various protocols. - Weneed to parameterize protocols, ex in smtp you have to expliciely request areply which is implicit with http. Http should be the first binding (pb iswhich kind of http?)
Protocol bindings, http:
SHould we use POST or should we have a "browser subset" Asynchronous/callbackthere should be conversion at intermediaries XP HTTP -> XP/SMTP ->XP/Napster
So what is low priority or not? it should be bindable to HTTP but not only. toteste the requirement, should we do other protocols?
Security and protocols. 2.4 exclude application level security. We haveinteraction with seciruty at transport or application. Security has to be inthe datamodel.
We said that the key to evolvability and multiple intermediaries is thecombination of an abstract data model with a protocol parameterization. Wesuggested that protocols other than the HTTP/(M)POST, such as GET, File, SMTP,etc. could/should be done as an appendix or a separate Note.
Many members were interested in this.
- Q: do you want to use GET?
- A: Yes so that we can bookmark it.
- Q: do we need to have a subset?
- A: we whould have the Get binding even if it is an appendix.
- A: browsers have limited http capability, a browser application would require to move structure data and browser can't make text/xml post.
- Q: does that astraction talk about kind of transaction?
- A: we didn't go that far.
- Q: the charter says that the WG will create a HTTP mapping, does it preclude other protocols? (then elude transport neutrality?)
- A: no.
- A: more on this, other external people will point out what are the limitation introduced by ex the http mapping. Unlike SOAP we need that XP is more transport neutral.
Subgroups requirements
Paul Cotton
[..]- Q: What do you think by modular?
- A: I didn't wrote that so I don't know.
- A: related to orthogonal and exensibility
Henrik Frystyk Nielsen
- Q: what do you mean by entity expansion
- A: I mean external entities
- Q: WHat are the reason why you ruled the out?
- A: You may have chicken and egg pb when you resolve and get entities.
- A: only external ones are problematic
- Q: what lightweight requirement is?
- A: it should be very similar to simple, by "as simple as other things doing this"
Glen Daniels
Alex Milowski
SOAP Presentation by Henrik Frystyk Nielsen
Seeslides and also theppt version.
XML Schema Presentation by Noah Mendelsohn
Seeslides in PDF.
Presentation of each subgroup requirements
Paul Cotton's group
Extracted righ out of the charter, plus list from people.
Glen Daniels noted that "shall be supported by the browser" isas aclient.
Henrik Frystyk Nielsen's
- What are you refering to when you talk about security mechanisms?
- Digest Authentication, XML DSig, etc.
Glen Daniels' group
Alex Milovski's
Walk through the list of requirement
- DR 001: How do we deal session-oriented communication?
- DR 002: What about BEEP? Maybe have another requirement. The list of protocol needs to be determined.
- DR 005: Clarification on XML idioms needed. We need to be compatible with other W3C technologies.
- DR 007: Browsers must be able (with the current technologies) to make XP requests and receive XP responses.
- Q: Why browsers and not mail clients?
- A: Browsers are in a world with forms and and they could use XP easily.
- Q: You should say more: you shouldn't do something that precludes you from using a browser.
- A: Not preclude is not sufficient.
We need to figure out what this means -> add an issue in order to clarify the use of XP (use cases). - DR 009:
- Q: Is there a standard way to embed XML within XML?
- A: There are a variety of ways, but no standard.
This requirement brings the issue of the processing model (talks about how to get a document in and then out and XP communication). - DR 010:
- Q: The word status implies that it is an application protocol. Is it at the envelope level or the application level?
- A: There might be situations in which you might want to send back an ack before an actual response.
- DR 013: Support intermediaries / routing information should be split.
- Q: all those things have support in front of them? Are we going to define them or just insure that it is going to work?
- A: Should be changed by provide.
- DR 015: replace entities by things. Talking about XP version 1, XP version 2, etc.
- Q: Is it going to be number based?
- A: Too much in detail.
- DR 016:
- Q: Is it a shall not preclude or are we going to provide a mechanism?
- A: We should investigate.
- DR 018: XP processors must support XML Schema. We need to define what an XP processor is.
- DR 019:
- Q: What is an object?
- A: an object is a SOAP end-point, i.e. a resource.
- A: It seems to me that it is related a programming model.
- C2: Everything on the Web is a resource. SOAP has the notion of passing by a URI which has a specified lifetime.
- DR 020: Better version later on.
There should be a boundary between the core specification and the rest.
- DR 021: Needs merging.
- DR 022: Needs merging for the first part. Issue: port number.
- DR 023: We should define in which XP stands.
- DR 024: Concerns about interoperability: set of rules to check that a message has been correctly formulated. It is related to language interaction. About a well specified and verifiable rules for RPC.
- DR 025 - dup
- DR 026 - rewording, the intent was that more than RPC should be supported (dup)
- DR 027 - dominant dup
- DR 028 - dup
- DR 029 - rephrase in "we should have use cases"
- DR 030 - reword connection oriented / connection oriented. This should be more explicit and connection with underlying support.
- DR 031 - dup
- DR 032 - do we allow small footprint implementation? (subset or not)
- DR 033 - do things put in XP should be human friendly or should it be possible to use more human friendly or allow interaction with human.
- DR 034 -
- DR 035 -
- DR 036 - separation btw core of the message and context information about the message? (proposed rewording) - sort out the use of metadata
This document will be sent out and the DR XXX will live forever and shouldbe used as reference for discussion. Those items belongs to the whole groupnot the subgroup that created them during the f2f.
- DR 037 -
- DR 038 - How does it relate to versionning? or just plain extensibility.
- DR 039 - dup
- DR 040 - do we need to support explicit binary data (or just base64 encoding is fine). Absolute NO on one side, yes on other side. (open for discussion) We should get requirements for binary binding.
- DR 041 - pref dup
- DR 042 - different level of abstraction may lead to conventions that put things outside of the envelope. SHould we transfer the unit of comm or the unit and potentially linked objects related? should be reworded in protocol unit (and then should the envelope be that unit). (discussion point)
- DR 043 -
- DR 044 -
- DR 045 - entity -> external entity. SOAP disallows dtd hence entities. (ie: SOAP uses a subset of xml) entities are slowly subsumed by more web like entities (xlink, even PIs).
- DR 046 - popular ones are smime/ssl/digital signatures
- DR 047 - general issue from XML (read XML infoset as background)
Telcon next week, Wednesday 8am PST, 11am EST, 4pm BST, 5pm MET, (@@ checkJapan and AUstralia time) number TBA soon
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