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

Dan and others.
 
Initially my reading was that a change of the SYNTAX was proposed/suggested.
That is clearly a NO-GO without deprecating the object and creating a new one.
 
My current understanding is that the only change suggested is to
change the UNITS clause from 0,25dBm into 0,25 dB.
 
If we look at the object in RGV3728, then we see:
   vdslPhysCurrSnrMgn OBJECT-TYPE
       SYNTAX       Integer32 (-127..127)
       UNITS        "0.25dBm"
       MAX-ACCESS   read-only
       STATUS       current
       DESCRIPTION
           "Noise Margin as seen by this Vtu with respect to its
           received signal in 0.25dB.  The effective range is
           -31.75 to +31.75 dB."
       REFERENCE    "T1E1.4/2000-009R3, Part 1, common spec"
        ::= { vdslPhysEntry 5 }
 
And so, the spec does show a discrepancy between the UNITS clause
and the DESCRIPTION clause. So if the subject matter experts agree
that 0,25dB is the correct units for this object, then I am fine to consider
the UNITS clause to have a typo and so to correct this as an errata.
 
Hope this helps,
Bert
----- Original Message -----
Sent: Monday, June 01, 2009 10:36 AM
Subject: Re: [Adslmib] RFC3728 (1788) (RFC Errata System)

I am afraid that such a change is not possible in an errata without
deprecating the object and defining a new object.

According to RFC 2578, Section 10.2

(6)  A UNITS clause may be added.

It is not clear if the UNITS clause can just be changed as Menachem
proposes. If both dB and dBm are valid units it looks like a change in
the semantics of the object. Even if this was just a typo I doubt the
change would be acceptable.

Deprecating an object and defining a new one requires a revision of the
MIB module. Such change cannot be made in an errata.

I would like to hear Bert's opinion.

Dan




> -----Original Message-----
> From: adslmib-bounces at ietf.org
> [mailto:adslmib-bounces at ietf.org] On Behalf Of Menachem Dodge
> Sent: Monday, June 01, 2009 9:59 AM
> To: Scott Baillie; Bert Wijnen (IETF)
> Cc: adslmib at ietf.org
> Subject: Re: [Adslmib] RFC3728 (1788) (RFC Errata System)
>
> Hi,
>
> So I believe there is now consensus that:
> 
>   The UNITS clause should be changed to "0.25dB" (instead of
> "0.25dBm").
>
> No other changes are needed to any of the other clauses.
>
>
>
> Are there any objections to accepting this errata?
>
> Best Regards,
> Menachem
>
>
>
> -----Original Message-----
> From: adslmib-bounces at ietf.org
> [mailto:adslmib-bounces at ietf.org] On Behalf Of Scott Baillie
> Sent: Thursday, May 28, 2009 8:07 PM
> To: Bert Wijnen (IETF)
> Cc: adslmib at ietf.org
> Subject: 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
> >        
> >         _______________________________________________
> >         Adslmib mailing list
> >         Adslmib at ietf.org
> >         https://www.ietf.org/mailman/listinfo/adslmib
> >        
> >        
> >        
> >        
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