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Re: [Adslmib] RFC3728 (1788) (RFC Errata System)



Hi All,

I think the UNITS clause should be changed to "0.25dB"
and this is not an incompatible change.

The MIB object in question holds a noise margin value
and is expressed in dB. The MIB object does not represent
a power level, it represents a ratio of power levels.
Because the MIB object represents a ratio there is no
need to mention power levels at all in the UNITS clause
or in the DESCRIPTION clause.

I have a few comments about some of the previous posts :

>Without an explicit or implicit reference level, decibel (dB) is
>undefined as it represents a ratio.  In our case (as with the ITU
>document), the reference level is explicitly specified in the UNITS
>clause.  If it were not, it would be implied by the context.  That is,
>we are measuring changes in audio levels in telephone circuits.  This
>has a VERY long and established history (the bel is named after
>Alexander Graham Bell, a decibel being one tenth of a bel).

I understand that it is convenient to use dBm when expressing power
levels in telephone circuits but the MIB object in question is a
noise margin, not a power level.

>However, if one felt forced, compelled, to be more specific, then,
>changing “dB” in the DESCRIPTION clause to “dBm” would be the more
>accurate change.

That change would be completely incorrect.

>Burt the reported proposal for the fix was going to change Integer32
>to Gaug32, or so I understood. That would be really bad I think.

No need to change the SYNTAX clause.

Regards,

Scott.

On Thu, 2009-05-28 at 00:01 +0200, Bert Wijnen (IETF) wrote:
> I can possibly live with updatinmg the description clause.
> Burt the reported proposal for the fix was going to change Integer32 
> to Gaug32, or so I understood. That would be really bad I think.
>  
> If the SYNTAXes and the value-ranges) all stay the same,
> then I guess that formally it would still be a semantic change, but 
> it is a matter of wording change that I could probably accept
> if the WG really has consensus on this.
>  
> Bert
>         ----- Original Message ----- 
>         From: Randy Presuhn 
>         To: adslmib at ietf.org 
>         Sent: Wednesday, May 27, 2009 8:36 PM
>         Subject: Re: [Adslmib] RFC3728 (1788) (RFC Errata System)
>         
>         
>         Hi -
>         
>         > From: "Ray, Robert E. (MSFC-NNM05AB50C)"
>         <robert.e.ray at nasa.gov>
>         > To: "Menachem Dodge" <Menachem.Dodge at ecitele.com>;
>         "Romascanu, Dan (Dan)" <dromasca at avaya.com>;
>         <adslmib at ietf.org>
>         > Cc: <smadar_t at rad.com>
>         > Sent: Wednesday, May 27, 2009 10:50 AM
>         > Subject: Re: [Adslmib] RFC3728 (1788) (RFC Errata System)
>         ...
>         > Because of this, I disagree completely with the Bert and Dan
>         on this because
>         > I don't think the semantics are changed at all.  I think the
>         context, and hence
>         > the reference level, is completely stated.  We are, after
>         all, dealing with
>         > telephone wires.
>         
>         Agreed.
>         
>         > However, if one felt forced, compelled, to be more specific,
>         then, changing
>         > "dB" in the DESCRIPTION clause to "dBm" would be the more
>         accurate change.
>         ...
>         
>         Agreed.  It's a case of the notation used in the DESCRIPTION
>         clause
>         being well-understood within the specialist community, but
>         being
>         potentially ambiguous outside of that community.  If the
>         change
>         is deemed necessary, it's nothing more than a clarification.
>         
>         Randy
>         
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