RE: Gauge32 as an INDEX (was: Index values of zero)

["Wijnen, Bert (Bert)" <bwijnen@lucent.com>]

Can we also add here that it would be good practice to document in the
DESCIRPTION clause why a zero value is used and what it means
in cases wehre it is actually a valid index.

Thanks,
Bert 

> -----Original Message-----
> From: C. M. Heard [mailto:heard@pobox.com]
> Sent: maandag 20 januari 2003 6:12
> To: Mreview (E-mail)
> Subject: Re: Gauge32 as an INDEX (was: Index values of zero)
> 
> 
> On Fri, 3 Jan 2003, Keith McCloghrie wrote:
> > As for 0, I think "a good reason MUST be specified" is bogus; where
> > must it be specified ?  and who decides whether it's good or not ??
> > If someone does use 0, they presumably have a reason which 
> they think
> > is a good reason, and if they specify it in private, then they have
> > complied with this rule.  Thus, all the rule really means 
> is that the
> > index value of 0 shouldn't be used arbitrarily, which I think is
> > already better expressed in the SMI as:
> >                                                ...  The use 
> of zero as
> >    a value for an integer-valued index object should be 
> avoided, except
> >    in special cases.
> > 
> > If there's anything lacking in that sentence from the SMI, it's that
> > there are two types of special cases:
> > 
> > 1. when 0 is semantically meaningful (e.g., a temperature of 0, or
> >    an IP-address of 0.0.0.0)
> > 2. when 0 has a special meaning (e.g., InterfaceIndexOrZero).
> 
> I've attempted to incorporate that wisdom into the guidelines 
> document.
> Here is that attempt:
> 
>    - For integer-valued objects that appear in an INDEX clause or for
>      integer-valued TCs that are to be used in an index column:
> 
>      - Unsigned32 with a range that excludes zero is RECOMMENDED for
>        most index objects.  It is acceptable to include zero in the
>        range when it is semantically significant or when it is used as
>        the index value for a unique row with special properties.
> 
>      - Integer32 or INTEGER with a non-negative range is acceptable.
>        Again, zero SHOULD be excluded from the range except when it is
>        semantically significant or when it is used as the index value
>        for a unique row with special properties.
> 
>      - Use of Gauge32 is appropriate for index objects that have gauge
>        semantics.
> 
> Let me know if you think that this is still broken or in need of
> further work.
> 
> //cmh
> 
>