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Re: [Adslmib] RFC3728 (1788) (RFC Errata System)
Hi Dan,
The proposed change is not a "change in semantics"
it is a correction for an incorrect UNIT clause.
In your message you state :
"If both dB and dBm are valid units"
They are not both valid in the context of a noise margin.
dB is a dimensionless quantity and dBm represents power
so they are not interchangeable.
Regards,
Scott
On Mon, 2009-06-01 at 10:36 +0200, Romascanu, Dan (Dan) wrote:
> 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
> > >
> > > _______________________________________________
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> > >
> > >
> > >
> > >
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