Export of Structured Data in IP Flow Information Export (IPFIX)
draft-ietf-ipfix-structured-data-06

[Ballot discuss]
This is a fine document, and I have no objection to it.

However, in reading it I discovered a question about the three-octet
length encoding. This shows in this documet through text such as:

      If the subTemplateMultiList is encoded as a Variable-Length
      Information Element in 255 or more octets, it is encoded with the
      Length field per Section 7 of [RFC5101] as follows:

      0                  1                  2                  3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      255      |      Length (0 to 65535)      |  Semantic    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

On examination of RFC 5101 I find this to be ambiguous. In particular,
it is not clear what would be meant by the length encoding ff,0,0. Is
that invalid, or does it mean a length of zero? I suspect it means a
length of zero, and that 255 means "use extended length encoding", and
does not mean "length is >= 255".

I am querying this with the editor of RFC 5101 and if we can agree a
clarification, I will raise an Erratum and request that the text in
this document is clarified.

[Ballot comment]
The Gen-ART Review by Suresh Krishnan on 12-Apr-2011 shows two places
  where the document is not clear.  Please address these two places.

  Section 2 says:

    However, the amount of information
    has become so important that, when dealing with highly granular
    information such as Flow information, a push mechanism (as opposed
    to a pull mechanism, such as SNMP) is the only solution for
    routers whose primary function is to route packets.

  Did you mean that "the amount of information is so large" or did you
  mean that "collecting this information has become so important" or
  did you mean something else?

  Section 2 also says:

    Furthermore, in order to reduce the export bandwidth requirements,
    the network elements have to integrate mediation functions to
    aggregate the collected information, both in space and time.
 
  What does aggregation based on space mean?

[Ballot discuss]
Appendix A appears to redefine or extend the XML (and XML schema) first provided in RFC 5102. At a minimum, this document therefore should say that it "Updates RFC 5102" (in the first-page header and in the Abstract). Furthermore, it's messy to just place some additional XML elements and XML schema definitions in Appendix A -- it would be cleaner to provide the complete (updated) XML and XML schema to make processing and testing easier. Finally, it is unclear what things like elementId="XXX" are supposed to mean -- are the three characters placeholders for values to be assigned by the IANA, or are they literal strings?

[Ballot comment]
A well written document.

The following are minor nits that I noticed during my review

In Section 2
"However, the amount of information has become so important..."
I think you mean "....so large...."

====
2.4. The Proposal

This is a standards track doc - therefore this is no longer a proposal.
=====

IANA understands that, upon approval of this document, there are four
actions which must be completed.

First, in the IPFIX informationElementDataTypes registry located in the
IP Flow Information Export (IPFIX) Information Elements registry located at:

http://www.iana.org/assignments/ipfix/ipfix.xml

three new data types are to be added.

Value:
Description: basicList
Reference: [ RFC-to-be ]

Value:
Description: subTemplateList
Reference: [ RFC-to-be ]

Value:
Description: subTemplateMultiList
Reference: [ RFC-to-be ]

Second, in the IPFIX informationElementSemantics registry located in the
IP Flow
Information Export (IPFIX) Information Elements registry located at:

http://www.iana.org/assignments/ipfix/ipfix.xml

a single new data type semantics is to be added.

Value:
Description:list
Reference: [ RFC-to-be ]

Third, in the IPFIX Information Elements registry located in the IP Flow
Information Export (IPFIX) Information Elements registry located at:

http://www.iana.org/assignments/ipfix/ipfix.xml

three new Information elements are to be added.

Value:
Name: basicList
Description: Specifies a generic Information Element with a basicList
abstract data type. For example, a list of port numbers, a list of
interface indexes, etc.
Data Type: basicList
Data Type Semantics: list
Status: current
Reference: [ RFC-to-be ]

Value:
Name: subTemplateList
Description: Specifies a generic Information Element with a
subTemplateList abstract data type.
Data Type: subTemplateList
Data Type Semantics: list
Status: current
Reference: [ RFC-to-be ]

Value:
Name: subTemplateMultiList
Description: Specifies a generic Information Element with a
subTemplateMultiList abstract data type.
Data Type: subTemplateMultiList
Data Type Semantics: list
Status: current
Reference: [ RFC-to-be ]

Fourth, IANA will create a new registry in the IP Flow Information
Export (IPFIX) Information Elements registry located at:

http://www.iana.org/assignments/ipfix/ipfix.xml

The new registry will be called the "IPFIX structured data types
semantics" subregistry. The registry is to be managed through Standards
Action. The IANA Matrix will use [RFC-to-be] as the reference for the
new registry. Values will range from 0x00 to 0xFF inclusive. The
following initial registrations will be made in the registry:

Value: 0x00
Name: noneOf
Description: The "noneOf" structured data type semantic specifies that
none of the elements are actual properties of the Data Record.
Reference: [ RFC-to-be ]

Value: 0x01
Name: exactlyOneOf
Description: The "exactlyOneOf" structured data type semantic specifies
that only a single element from the structured data is an actual
property of the Data Record. This is equivalent to a logical XOR operation.
Reference: [ RFC-to-be ]

Value: 0x02
Name: oneOrMoreOf
Description: The "oneOrMoreOf" structured data type semantic specifies
that one or more elements from the list in the structured data are
actual properties of the Data Record. This is equivalent to a logical OR
operation.
Reference: [ RFC-to-be ]

Value: 0x03
Name: allOf
Description: The "allOf" structured data type semantic specifies that
all of the list elements from the structured data are actual properties
of the Data Record.
Reference: [ RFC-to-be ]

Value: 0x04
Name: ordered
Description: The "ordered" structured data type semantic specifies that
elements from the list in the structured data are ordered.
Reference: [ RFC-to-be ]

Value: 0xFF
Name: undefined
Desicription: The "undefined" structured data type semantic specifies
that the semantic of list elements is not specified, and that, if a
semantic exists, then it is up to the Collecting Process to draw its own
conclusions. The "undefined" structured data type semantic is the
default structured data type semantic.
Reference: [ RFC-to-be ]

IANA understand that these are the only actions required upon approval
of this document.

State changed to In Last Call from Last Call Requested.

The following Last Call Announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Subject: Last Call:  (Export of Structured Data in IPFIX) to Proposed Standard


The IESG has received a request from the IP Flow Information Export WG
(ipfix) to consider the following document:
- 'Export of Structured Data in IPFIX'
  as a Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2011-03-21. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-ipfix-structured-data/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-ipfix-structured-data/

Shepherding Document by Nevil Brownlee:

Shepherd Document for draft-ietf-ipfix-structured-data-04.txt

  (1.a) Who is the Document Shepherd for this document? Has the
        Document Shepherd personally reviewed this version of the
        document and, in particular, does he or she believe this
        version is ready for forwarding to the IESG for publication?

  Nevil Brownlee.  I have reviewed this draft, I believe it's ready
  for publication.

  (1.b) Has the document had adequate review both from key WG members
        and from key non-WG members? Does the Document Shepherd have
        any concerns about the depth or breadth of the reviews that
        have been performed?

  Yes. It was developed over the last two years, and has had extensive
  discussion on the IPFIX list.  I have no concerns about its reviews.

  (1.c) Does the Document Shepherd have concerns that the document
        needs more review from a particular or broader perspective,
        e.g., security, operational complexity, someone familiar with
        AAA, internationalization or XML?

  No.  This is a Standards Track document describing extensions
  to the IPFIX Information Model (RFC 5102), and the implications
  of these extensions for the IPFIX Protocol (RFC 5101).
  It should not impact any other areas.

  (1.d) Does the Document Shepherd have any specific concerns or
        issues with this document that the Responsible Area Director
        and/or the IESG should be aware of? For example, perhaps he
        or she is uncomfortable with certain parts of the document, or
        has concerns whether there really is a need for it. In any
        event, if the WG has discussed those issues and has indicated
        that it still wishes to advance the document, detail those
        concerns here. Has an IPR disclosure related to this document
        been filed? If so, please include a reference to the
        disclosure and summarize the WG discussion and conclusion on
        this issue.

  I regard this draft as a necessary and important step forward
  for IPFIX.
  No IPR disclosure has been made for this draft.

  (1.e) How solid is the WG consensus behind this document? Does it
        represent the strong concurrence of a few individuals, with
        others being silent, or does the WG as a whole understand and
        agree with it? 

  The WG has reached full consensus on this draft.

  (1.f) Has anyone threatened an appeal or otherwise indicated extreme
        discontent? If so, please summarise the areas of conflict in
        separate email messages to the Responsible Area Director. (It
        should be in a separate email because this questionnaire is
        entered into the ID Tracker.)

  No.

  (1.g) Has the Document Shepherd personally verified that the
        document satisfies all ID nits? (See the Internet-Drafts Checklist
        and http://tools.ietf.org/tools/idnits/). Boilerplate checks are
        not enough; this check needs to be thorough. Has the document
        met all formal review criteria it needs to, such as the MIB
        Doctor, media type and URI type reviews?

  Yes.  The checker finds no issues with this draft.

  (1.h) Has the document split its references into normative and
        informative? Are there normative references to documents that
        are not ready for advancement or are otherwise in an unclear
        state? If such normative references exist, what is the
        strategy for their completion? Are there normative references
        that are downward references, as described in [RFC3967]? If
        so, list these downward references to support the Area
        Director in the Last Call procedure for them [RFC3967].

  Yes.  All the normative references are to RFCs, there are no
  downward references.

  (1.i) Has the Document Shepherd verified that the document IANA
        consideration section exists and is consistent with the body
        of the document? If the document specifies protocol
        extensions, are reservations requested in appropriate IANA
        registries? Are the IANA registries clearly identified? If
        the document creates a new registry, does it define the
        proposed initial contents of the registry and an allocation
        procedure for future registrations? Does it suggest a
        reasonable name for the new registry? See [RFC5226]. If the
        document describes an Expert Review process has Shepherd
        conferred with the Responsible Area Director so that the IESG
        can appoint the needed Expert during the IESG Evaluation?

  Yes.  The draft "specifies several new IPFIX abstract data types,
      a new IPFIX Data Type Semantic, and several new Information
      Elements. These require the creation of two new IPFIX registries
      and updating the existing IPFIX Information Element registry."
  These requirements are clearly explained.

  (1.j) Has the Document Shepherd verified that sections of the
        document that are written in a formal language, such as XML
        code, BNF rules, MIB definitions, etc., validate correctly in
        an automated checker?

  There are no sections written in a formal language.

  (1.k) The IESG approval announcement includes a Document
        Announcement Write-Up. Please provide such a Document
        Announcement Write-Up? Recent examples can be found in the
        "Action" announcements for approved documents. The approval
        announcement contains the following sections:

    Technical Summary
  This document specifies an extension to the IP Flow Information
  eXport (IPFIX) protocol specification in [RFC5101] and the IPFIX
  information model specified in [RFC5102] to support hierarchical
  structured data and lists (sequences) of Information Elements in
  data records.  This extension allows definition of complex data
  structures such as variable-length lists and specification of
  hierarchical containment relationships between Templates.
  Finally, the semantics are provided in order to express the
  relationship among multiple list elements in a structured data
  record.

    Working Group Summary
  Work on this draft began in March 2009.  Its development has had
  strong co-operative work from WG members in Europe, Japan and
  elsewhere.  Its WG Last Call generated enough comments that we
  ran a second WGLC, this version represents  the WG consensus.

    Document Quality
        Are there existing implementations of the protocol? Have a
        significant number of vendors indicated their plan to
        implement the specification? Are there any reviewers that
        merit special mention as having done a thorough review,
        e.g., one that resulted in important changes or a
        conclusion that the document had no substantive issues? If
        there was a MIB Doctor, Media Type or other expert review,
        what was its course (briefly)? In the case of a Media Type
        review, on what date was the request posted?
  I'm not aware of any current implementations, but the list
  discussion makes me think that they do exist.
  There has been so much list discussion of this draft that I
  can't really single out any particular reviewer.


Nevil Brownlee
8 Feb 11