Subject: [IPFIX] AD review of draft-ietf-ipfix-flow-selection-tech-10.txt

From: "Romascanu, Dan (Dan)" <[email-masked]>
Date: Wed, 21 Mar 2012 17:41:52 +0100

Please find below the AD review of
draft-ietf-ipfix-flow-selection-tech-10.txt. 

The document is in a good enough shape to be sent to IETF LC. Please
consider my comments together with the other IETF LC comments. 

The comments are divided into T (Technical) and E (Editorial). 

T1. In section 5.1.2: 

   Nevertheless there MAY be the incentive to apply Hash-
   based Flow Filtering not on the packet level during the Metering
   Process, for example when the size of the selection range and
   therefore the sampling probability is dependent on the number of
   observed flows.

I think that the usage of a capitalized RFC 2119 MAY is not justified
here. 

T2. In section 6.1 please provide references for the hash functions
mentioned as possible functions.

T3. In section 7: 

   In this section we describe Information Elements (IEs) that SHOULD be
   exported by a flow selection process in order to support the
   interpretation of measurement results from flow measurements where
   only some flows are selected.  

Why is this a SHOULD and not a MUST? What are the exception cases? 

T4. Also in section 7: 

   All counters SHOULD be exported and reset when a new
   measurement interval starts.

Why is this a SHOULD and not a MUST? What are the exception cases? Are
exporting counters and reset of counters independent, in other words can
some counters be exported but not reset when a new measurement interval
starts? 

T5. Where are allocated all the IDs marked as TBD in the table in
Section 7? I do not see a request for allocation in the IANA
considerations section. What am I missing?

T6. Even if configuration methods and protocols are out of the scope of
this document I believe that this statement in the Security
Considerations section is not sufficient: 

   Nevertheless, a full analysis and assessment of threats for
   configuration and reporting has to be done if configuration or
   reporting methods are proposed.

I think that this document needs at least make a complete assessment of
the threats and place requirements in the configuration and reporting
methods to be later defined. 

E1. Three of the missing references prompted up by idnits seem to be
indeed missing references: 

  == Missing Reference: 'RFC5226' is mentioned on line 868, but not
     defined
     'administered by IANA and are subject to Expert Review [RFC5226...'

  == Missing Reference: 'I-D.dkcm-ipfix-rfc5815bis' is mentioned on line
     1330, but not defined
     'according to the procedures set forth in
[I-D.dkcm-ipfix-rfc5815b...'

  == Missing Reference: 'GoRe07' is mentioned on line 1372, but not
     defined
'[GoRe07]....'

E2. Drop the comma from 'The reason is, that flow-state dependent ...'

E3. Section 5.2.1:

Systematic sampling MAY BE applied during the Metering
   Process.

BE needs not be capitalized. 

E4. It would be useful to nuumber the Tables in the document like the
one in Section 6, for later references in other documents. 

Regards,

Dan