Re: [IPFIX] New WG Last Call for draft-ietf-ipfix-flow-selection-tech-06.txt

[Brian Trammell <[e-mail]>]

Hi, Nevil, all,

The following is intended as a WGLC comment on flow-selection-tech. It will not be my only one; however, it identifies an issue I've seen in a cursory review of the document which I believe could benefit from some discussion:

Is this document intended to update RFC 5470? I'm not convinced this is necessary; e.g. RFC 6235 defines a flow-modifying intermediate process, and shows how it could be integrated into various stages within the IPFIX Architecture, without introducing a new model of how data is handled in the architecture. If each additional intermediate process definition updates the architecture, the architecture becomes confusing, and subsequently useless.

If the authors and the WG believe it is necessary to update 5470 to support flow selection, I would _strongly_ suggest reviewing all new terminology, as the proposed terms collide with existing terms of art in network measurement. Specifically, there are two serious problems here. First, I'm not aware of any use of the word "classification" with respect to the associating of packets with flows; classification instead seems primarily to be used when associating a label with a packet of a flow (e.g., application classification). Second, while packets are indeed aggregated into flows, the word "aggregation" in this draft is used in a completely different way than in either -ipfix-a9n or in RFCs 5982 or 6183. This could lead to confusion.

More detailed comments to follow.

Best regards,

Brian

On May 24, 2011, at 11:27 PM, Nevil Brownlee wrote:

> 
> Hi all:
> 
> Thanks very much to all the authors of the flow-selection draft,
> it does indeed look much better.  Since there's so much new material
> in it, we need to run a new WG LC on it - that start's today, and
> will finish on Friday, 10 June.  Do please read it anew, and send
> comments to the list.  Brief comments such as "yes, this looks fine
> now" are welcome, of course!
> 
> Cheers, Nevil
> 
> 
> On 23/05/11 9:30 PM, Zseby, Tanja wrote:
>> Hi all,
>> 
>> we worked on a major revision of the flow selection draft and just submitted a new version (see below). Among other changes we now provide a much improved classification of methods, which is more consistent with the PSAMP packet selection documents.
>> Many thanks to all who provided comments.
>> 
>> Changes:
>>  - Flow recording process removed
>>  - Clarification of difference between flow selection and packet selection
>>  - Distinguished flow filtering and flow sampling similar to PSAMP
>>  - Flow selection in the metering process either before aggregation or after aggregation
>>  - Integrated Flow-state dependent packet selection
>>  - Supporting arbitrary  key space subsets with property match flow filtering
>>  - Removed timestamp IEs for reporting
>>  - Mediator integrated in first picture
>>  - Configuration parameters and IEs redefined and re-named
>>  - Many rewording, shortened several paragraphs to improve readability
>> 
>> Kind regards
>> Tanja
>> 
>> 
>> -----Ursprüngliche Nachricht-----
>> Von: [e-mail] [mailto:[e-mail]] Im Auftrag von [e-mail]
>> Gesendet: Montag, 23. Mai 2011 11:21
>> An: [e-mail]
>> Cc: [e-mail]
>> Betreff: [IPFIX] I-D Action: draft-ietf-ipfix-flow-selection-tech-06.txt
>> 
>> A New Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the IP Flow Information Export Working Group of the IETF.
>> 
>> 	Title           : Flow Selection Techniques
>> 	Author(s)       : Salvatore D'Antonio
>>                           Tanja Zseby
>>                           Christian Henke
>>                           Lorenzo Peluso
>> 	Filename        : draft-ietf-ipfix-flow-selection-tech-06.txt
>> 	Pages           : 25
>> 	Date            : 2011-05-23
>> 
>>    Flow selection is the process of selecting a subset of flows from all
>>    flows observed at an observation point.  Flow selection reduces the
>>    effort of post-processing flow data and transferring flow records.
>>    This document describes motivations for flow selection and presents
>>    flow selection techniques.  It provides an information model for
>>    configuring flow selection techniques and discusses what information
>>    about a flow selection process should be exported.
>> 
>> 
>> 
>> A URL for this Internet-Draft is:
>> http://www.ietf.org/internet-drafts/draft-ietf-ipfix-flow-selection-tech-06.txt
>> 
>> Internet-Drafts are also available by anonymous FTP at:
>> ftp://ftp.ietf.org/internet-drafts/
>> 
>> This Internet-Draft can be retrieved at:
>> ftp://ftp.ietf.org/internet-drafts/draft-ietf-ipfix-flow-selection-tech-06.txt
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> 
> 
> -- 
> ---------------------------------------------------------------------
> Nevil Brownlee                    Computer Science Department | ITS
> Phone: [phone] x88941             The University of Auckland
> FAX: [phone]   Private Bag 92019, Auckland 1142, New Zealand
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