Subject: RE: [ipfix] [issue] INFO-18 Field semantics (counters vs. quant ities)

From: "MEYER,JEFFREY D (HP-Cupertino,ex1)" <[email-masked]>
Date: Sat, 22 Nov 2003 18:26:35 -0500

Tal,
 
  Take a look at the text in the current draft:

http://www.ipdr.org/documents/ipfix/infomodel/draft-ietf-ipfix-info-02.html#
anchor25
<http://www.ipdr.org/documents/ipfix/infomodel/draft-ietf-ipfix-info-02.html
#anchor25> 
 
  Around Integer Semantic Qualifiers.  The terms I chose were:
    - quantity
    - counter
    - identifier
    - flags
 
  I did not use guage.  I don't think the definitions of counter, identifier
or flags or their names should be too contentious.
 
  The definition I used for quantity sounds in line with the discussion in
your e-mail.  However, the name "quantity" may be up for debate.  Note
however I indicate that "quantity" is the default semantic when none is
specified.  So in the information model, these show up as unqualified
integral types (byte, unsignedByte, short, unsignedShort, int, unsignedInt,
long, unsignedLong).
 
  There are currently no counters identified in the information model.
Proposing some of these would probably be appropriate.  e.g. byteCounter,
droppedPacketCounter, etc. for applications which benefit from counter vs.
quantity semantics (i.e. not classic NF, maybe exported flow aggregates, or
meter statistics).
 
Regards,
 
  Jeff Meyer

-----Original Message-----
From: Tal Givoly [mailto:[email-masked]]
Sent: Saturday, November 22, 2003 3:14 PM
To: MEYER,JEFFREY D (HP-Cupertino,ex1); 'Ipfix Wg' (E-mail)
Subject: RE: [ipfix] [issue] INFO-18 Field semantics (counters vs.
quantities)

Jeff,
 
I don't believe that "gauge", "quantities" or "identifiers" are good enough
one-word-descriptions for "delta values" we refered to sometimes as
"integers". I made an earlier recommendation on terminology and didn't see
any response (also see
http://ipfx.doit.wisc.edu/list/ipfix/archive/2109.html
<http://ipfx.doit.wisc.edu/list/ipfix/archive/2109.html>  ).
 
Tal

-----Original Message-----
From: majordomo listserver [mailto:[email-masked]]On Behalf Of
MEYER,JEFFREY D (HP-Cupertino,ex1)
Sent: Friday, November 21, 2003 1:12 PM
To: 'Ipfix Wg' (E-mail)
Subject: [ipfix] [issue] INFO-18 Field semantics (counters vs. quantities)

Issue:  INFO-18  Field semantics (counters vs. quantities)
Description: 
  Counters vs. Identifiers (OVMS) vs. Discrete Quantities (Gauge?) 
   - explicitly distinguish between the two.  However, when it comes to
     storing results, e.g. to do reporting, a counter is pretty much
     useless (i.e. a collector will likely turn a counter into an
     integer).
     
   - Counters may NOT have a variable length, as this makes wrap 
     calculation problematic.
     
   - Needs discussion in protocol encoding section.  I.e. something like:
   
      When specifying field length in templates an implementation MAY
      chose to specify a length shorter than that associated with the
      declared integral information element type from the information model.
      This can reduce overall message lengths when a particular 
      implementation knows it will only encounter values in a smaller
      range which can fit in fewer bytes.
      
      Sizes should be downgraded in powers of two in bytes:  i.e. 
      1, 2 or 4.  Currently there are no integral types greater than 
      8 bytes.  If these come into vogue then downgrading from 16 to
      8 say would also be an option.
 
  http://ipfix.doit.wisc.edu/archive/1981.html
<http://ipfix.doit.wisc.edu/archive/1981.html>

---

From: "Tal Givoly" <[email-masked]>
Date: Sat, 22 Nov 2003 21:59:41 -0800

I concur that "quantity" works. I wonder whether we will have non-integer
quantities, but no reason to preclude those at this time, so the separation
from data type is good. it is perhaps interesting to note that "counter"
implies non-negative integer data type whereas even though quantity will
typically be non-negative integer, that is not implied in the definition.

Tal

  -----Original Message-----
  From: MEYER,JEFFREY D (HP-Cupertino,ex1) [mailto:[email-masked]]
  Sent: Saturday, November 22, 2003 3:27 PM
  To: 'Tal Givoly'; MEYER,JEFFREY D (HP-Cupertino,ex1); 'Ipfix Wg' (E-mail)
  Subject: RE: [ipfix] [issue] INFO-18 Field semantics (counters vs.
quantities)

  Tal,

    I did not use guage.  I don't think the definitions of counter,
identifier or flags or their names should be too contentious.

  Regards,

    Jeff Meyer
    -----Original Message-----
    From: Tal Givoly [mailto:[email-masked]]
    Sent: Saturday, November 22, 2003 3:14 PM
    To: MEYER,JEFFREY D (HP-Cupertino,ex1); 'Ipfix Wg' (E-mail)
    Subject: RE: [ipfix] [issue] INFO-18 Field semantics (counters vs.
quantities)

    Jeff,

    I don't believe that "gauge", "quantities" or "identifiers" are good
enough one-word-descriptions for "delta values" we refered to sometimes as
"integers". I made an earlier recommendation on terminology and didn't see
any response (also see
http://ipfx.doit.wisc.edu/list/ipfix/archive/2109.html ).

    Tal
      -----Original Message-----
      From: majordomo listserver [mailto:[email-masked]]On
Behalf Of MEYER,JEFFREY D (HP-Cupertino,ex1)
      Sent: Friday, November 21, 2003 1:12 PM
      To: 'Ipfix Wg' (E-mail)
      Subject: [ipfix] [issue] INFO-18 Field semantics (counters vs.
quantities)

         - explicitly distinguish between the two.  However, when it comes
to

         - Needs discussion in protocol encoding section.  I.e. something
like:

            declared integral information element type from the information
model.

---

From: Stewart Bryant <[email-masked]>
Date: Mon, 24 Nov 2003 10:33:11 +0000

4.21.3 Identifier

An integral value which serves as an identifier. Specifically mathematical 
operations on two identifiers (aside from the equality operation) are 
meaningless. E.g. Autonomous System Id 1 * Autonomous System Id 2 is meaningless.

SB> An identifier is an unsigned object.

Stewart

MEYER,JEFFREY D (HP-Cupertino,ex1) wrote:

> http://www.ipdr.org/documents/ipfix/infomodel/draft-ietf-ipfix-info-02.html#anchor25
>  
>   The definition I used for quantity sounds in line with the discussion 
> in your e-mail.  However, the name "quantity" may be up for debate.  
> Note however I indicate that "quantity" is the default semantic when 
> none is specified.  So in the information model, these show up as 
> unqualified integral types (byte, unsignedByte, short, unsignedShort, 
> int, unsignedInt, long, unsignedLong).
>  
> Proposing some of these would probably be appropriate.  e.g. 
> byteCounter, droppedPacketCounter, etc. for applications which benefit 
> from counter vs. quantity semantics (i.e. not classic NF, maybe exported 
> flow aggregates, or meter statistics).
>  
> Regards,
>  
>   Jeff Meyer
> 
>     enough one-word-descriptions for "delta values" we refered to
>     sometimes as "integers". I made an earlier recommendation on
>     terminology and didn't see any response (also see
>         From: majordomo listserver
>         [mailto:[email-masked]]On Behalf Of MEYER,JEFFREY D
>         (HP-Cupertino,ex1)

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