Subject: Fwd: [httpbis] #523: Gen-ART Last Call review draft-ietf-httpbis-p1-messaging-25

From: Julian Reschke <[email-masked]>
Date: Tue, 03 Dec 2013 21:30:42 +0100

(FYI)

-------- Original Message --------
Subject: [httpbis] #523: Gen-ART Last Call review 
draft-ietf-httpbis-p1-messaging-25
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Date: Tue, 03 Dec 2013 16:51:59 -0000
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#523: Gen-ART Last Call review draft-ietf-httpbis-p1-messaging-25
-------------------------+-------------------------------------------------
  Reporter:               |      Owner:  draft-ietf-
   [email-masked]  |  [email-masked]
      Type:  design       |     Status:  new
  Priority:  normal       |  Milestone:  unassigned
Component:               |   Severity:  In IETF LC
   p1-messaging           |     Origin:
  Keywords:               |
-------------------------+-------------------------------------------------
  Document: draft-ietf-httpbis-p1-messaging-25

  Reviewer: Meral Shirazipour

  Review Date: 2013-11-18/2013-12-02

  IETF LC End Date: End of November (special deadline)

  IESG Telechat date: 2013-12-19

  Summary:

  This draft is almost ready to be published as Proposed Standard but I have
  some comments.

  Major issues:

  none

  Minor issues:

  Part 1 of:

  **draft-ietf-httpbis-p1-messaging (82 pages)

  draft-ietf-httpbis-p2-semantics (98 pages)

  *draft-ietf-httpbis-p4-conditional (27 pages)

  draft-ietf-httpbis-p5-range (24 pages)

  *draft-ietf-httpbis-p6-cache (41 pages)

  draft-ietf-httpbis-p7-auth (18 pages)

  draft-ietf-httpbis-method-registrations (7 pages)

  draft-ietf-httpbis-authscheme-registrations (5 pages)

  ** this review

  * also reviewed my me (some of comments/suggestions below may apply to all
  reviews)

  -General comment 1, I am not very keen with the idea of splitting the http
  standard in so many RFCs.

  It is hard to follow and the protocol is not complex enough to justify
  these lengthy documents.

  I would have rather see 1 concise standard RFC and few Extension RFCs,
  Informational or BCP RFCs.

  RFC2616 was ~176 pages, looking at Appendix B of the draft for changes
  since RFC2616, makes me wonder why so much extra text was required (~300
  pages).

  Constructive comment:

                  -Perhaps in part 1 give a suggestion on how to use/read
  these documents (RFCs). Could any of them be skipped at first for a simple
  implementation?

                  I think it is worthwhile spending minimum 2-3 pages to
  summarize the various documents (Parts) and suggest how to use them best.

                  -Most people use www on a daily basis, some of the
  concepts could be better explained with every day experienced examples
  rather than abstract explanation.

  -General comment 2, throughout the text there is mention of security risks
  yet this is not a complete list for security issues in http.

  It would be beneficial to also have a separate document for all security
  risks to be considered by server and client implementors.

  Nits/editorial comments:

  -[Page 5] in the intro, right after it says "This HTTP/1.1 specification
  obsoletes and moves to historic status RFC 2616....", it would

  help to add a reference to Appendix B and mention this is where the
  differences with RFC2616 is listed.

  -

  [Page 5,6], Section 1, this statement is not clear. Are we talking about
  one HTTP transaction changing info on the server/data base?

  "

  If the communication is considered in isolation, then successful actions

     ought to be reflected in corresponding changes to the observable

     interface provided by servers.  However, since multiple clients might

     act in parallel and perhaps at cross-purposes, we cannot require that

     such changes be observable beyond the scope of a single response.

     This document describes the architectural elements that are used or

     referred to in HTTP, defines the "http" and "https" URI schemes,

     describes overall network operation and connection management, and

     defines HTTP message framing and forwarding requirements.  Our goal

     is to define all of the mechanisms necessary for HTTP message

     handling that are independent of message semantics, thereby defining

     the complete set of requirements for message parsers and message-

     forwarding intermediaries.

  "

  -[Page 11], Section 2.3, "Instead, an interception proxy filters or
  redirects outgoing TCP port 80 packets (and occasionally other common port
  traffic)."

  Not sure if "occasionally other common port traffic" means port 443?

  If not, for sake of completeness, we could say : "redirects outgoing TCP
  ports 80 and 443 packets".

  -[Page 12], Section 2.5 not clear what is meant by (social) requirements.
  An example may clarify:

  "Additional (social) requirements are placed on implementations,

     resource owners, and protocol element registrations when they apply

     beyond the scope of a single communication.

  "

  -[Page 13], not a comment for this draft but in general, has the WG
  considered a BCP for general error handling, in line with the example
  given after this sentence:

  "

  HTTP does not define

     specific error handling mechanisms except when they have a direct

     impact on security, since different applications of the protocol

     require different error handling strategies.

  "

  -[Page 15], if the statement below is a well-known and often happening
  scenario it would help to give at least

  one example of how a client can deduce that by going to a lower version of
  HTTP the problem(?) will be fixed.

  (Note that 2 paragraphs below give examples for the server case.)

  "

  A client MAY send a lower request version if it is known that the

     server incorrectly implements the HTTP specification, but only after

     the client has attempted at least one normal request and determined

     from the response status code or header fields (e.g., Server) that

     the server improperly handles higher request versions.

  "

  -[Page 15],can the server send this error message to refuse service based
  on e.g. connection identification or other reasons? Then how can the
  client

  address the problem if in reality it was not related to the version of
  HTTP?

  "

  A server can send a 505

     (HTTP Version Not Supported) response if it wishes, for any reason,

     to refuse service of the client's major protocol version.

  "

  -[Page 16], would it be ok to use MAY? If so it would be clearer to use
  MAY. : "A recipient MAY..."

  "

  A recipient can assume that a

     message with a higher minor version, when sent to a recipient that

     has not yet indicated support for that higher version, is

     sufficiently backwards-compatible to be safely processed by any

     implementation of the same major version.

  "

  -[Page 17], Section 2.7.1 first line:   "...for the purpose of minting
  identifiers".

  suggestion: if another word than "minting" (e.g. generating, creating),
  could be used it would be easier to read that section.

  (also used in section 2.7.2)

  -[Page 17], "port 80 is assumed", should it be "SHOULD BE" or "MUST BE" ?

  "If the port subcomponent is empty or not given, then TCP port

     80 is assumed (the default reserved port for WWW services).

  "

  -[Page 17], "non-interim" , not clear how it can be determines as non-
  interim (no other message in between? or under a certain peruiod of time?)

  Also the term "authoritative" is introduced and should be defined in this
  context.

  "

  If the server responds to that request with a non-interim

     HTTP response message, as described in Section 6 of [Part2], then

     that response is considered an authoritative answer to the client's

     request.

  "

  -[Page 21], Should it be section 5.3?

  "

  Recipients typically parse the request-line into its component parts

     by splitting on whitespace (see Section 3.5), ...

  "

  -[Page 21], just verifying is it three or tree?

  "

  ..., since no whitespace is allowed in the three components.

  "

  -[Page 52], refers to an obsoleted RFC. Maybe repeating the explanation in
  this draft would be a better idea.

  "

  A proxy server MUST NOT maintain a persistent connection with an

     HTTP/1.0 client (see Section 19.7.1 of [RFC2068] for information and

     discussion of the problems with the Keep-Alive header field

     implemented by many HTTP/1.0 clients).

  "

  -[Page 54], suggestion for clarity: "through the same server"--->"through
  the same proxy server"

  "

  Proxy servers might make

     this a higher value since it is likely that the client will be making

     more connections through the same server.

  "

  - [Page 65], Security section, is it exhaustive? Would it be better to
  have a separate draft to discuss all security issues related to HTTP?

  (also referring to comments from Kathleen Moriarty on other parts of this
  bis) [See comment 2 in "minor issues" section above]

  Best Regards,

  Meral

-- 
Ticket URL: <http://trac.tools.ietf.org/wg/httpbis/trac/ticket/523>
httpbis <http://tools.ietf.org/wg/httpbis/>

---

From: Julian Reschke <[email-masked]>
Date: Fri, 06 Dec 2013 10:37:22 +0100

>   since RFC2616, makes me wonder why so much extra text was required (~300

It depends on how you count. You included repeated boilerplate, 
collected ABNFs, indexes, change logs, etc.

When I count the pages containing the actual spec, I get something like 
235 pages. Please also keep in mind that we have included stuff from 
other specs, such as the authentication framework and CONNECT.

And yes, we could have added more prose or examples. Or we could have 
tried to reduce the size. We could have organized the document 
differently. We could have attempted to have an exhaustive list of 
security considerations. But what we have right now is the result of a 
multi-year work, has passed WGLCs and IETF LC, and I don't think that 
now is the right time to make any additional changes except for fixing 
actual bugs.

(we'll get to the non-editorial feedback later)

Best regards, Julian

---

From: Julian Reschke <[email-masked]>
Date: Sun, 08 Dec 2013 10:50:49 +0100

Meral,

>   differences with RFC2616 is listed.

That would be somewhat misleading as we have "changes from 2616" 
sections in all six parts.

>      forwarding intermediaries.

We talk about observable changes because that's all what's relevant for 
the protocol.

> ...

Nope (at least that's my understanding).

>      require different error handling strategies.

No.

>      the server improperly handles higher request versions.

The idea is that if the server is known not to implement 1.1 properly 
than 1.0 is the only available feedback. I thought that's clear enough.

>      to refuse service of the client's major protocol version.

This status code is for signaling that the server doesn't support the 
request protocol version. Nothing more.

>      implementation of the same major version.

Exactly how is that clearer?

>   (also used in section 2.7.2)

I believe the term "minting" is very commonly used.

>      80 is assumed (the default reserved port for WWW services).

It's a statement of fact, no interop requirement.

>      that response is considered an authoritative answer to the client's

As defined in Part2, Section 6; that is, a status code other that 1xx.

>      by splitting on whitespace (see Section 3.5), ...

No.

>   ..., since no whitespace is allowed in the three components.

It is "three".

>      implemented by many HTTP/1.0 clients).

I think it's preferable not to inline that information; I think some 
people already complained about the spec being too long ;-)

> ...

Best regards, Julian

---

From: Julian Reschke <[email-masked]>
Date: Thu, 19 Dec 2013 18:00:08 +0100

On 2013-12-09 23:42, Meral Shirazipour wrote:
> "non-interim" = ?

Non-1xx.

See 
<http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p2-semantics-25.html#rfc.section.6.2>

> "authoritative" means coming from origin server?

No, it means "final" as opposed to "interim".

Best regards, Julian

---

From: Jari Arkko <[email-masked]>
Date: Thu, 19 Dec 2013 16:42:01 +0000

Meral, Julian,

> Hi Julian,
>   I agree that it may be too late to make drastic changes. Please consider the below comments though, it may help:
> 
> "
> Constructive comment: 
>     -Perhaps in part 1 give a suggestion on how to use/read these documents (RFCs). Could any of them be skipped at first for a simple implementation? I think it is worthwhile spending minimum 2-3 pages to summarize the various documents (Parts) and suggest how to use them best.
> "

FWIW, I think this would be useful.

Jari

---

From: Jari Arkko <[email-masked]>
Date: Thu, 19 Dec 2013 16:47:58 +0000

Meral: thank you for your detailed review. You have done many reviews on this document set. Very much appreciated!

I have a couple of comments below on the discussion, not commenting on this already agreed:

> Actually going back to my comment :
> "   -Perhaps in part 1 give a suggestion on how to use/read these documents (RFCs). Could any of them be skipped at first for a simple implementation?
>      I think it is worthwhile spending minimum 2-3 pages to summarize the various documents (Parts) and suggest how to use them best.
> "

I agree that we should not change the structure of the documents at this stage. As I said in the other mail, I think a list of other documents and their primary use might have been a useful thing to do.

> So it is other ports than 80/443? In this case, you may want to add 443 to the text.

I think the situation is that we have multiple such ports… not sure mentioning the specific ones is necessary.

> Please refer to http://tools.ietf.org/html/rfc2119 for extra significance.

I think "MAY" would be my choice, but I understand the authors if they have a reason to try to stay with language and requirements that existing documents and implementations have used.

> I am not the best judge either (but I had to google it).

I think this term is occasionally used, probably ok.

> "authoritative" means coming from origin server?

Was there a response, Julian?

Jari

---

From: "Roy T. Fielding" <[email-masked]>
Date: Thu, 19 Dec 2013 11:48:15 -0800

On Dec 19, 2013, at 9:00 AM, Julian Reschke wrote:

> See <http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p2-semantics-25.html#rfc.section.6.2>
> 

In the quote from p1, "authoritative" is used according to its
common English definition:

  https://www.google.com/search?q=define+authoritative

and doesn't imply that the server is the origin server (it could
be a CDN), though it supposedly operates on behalf of the origin.

....Roy