Re: Attribute Name Length Bounds

["Larry S. Bartz" <lbartz@parnelli.indy.cr.irs.gov>]

Chris Apple wrote, On 06/13/03 10:44:
> I was thinking more along the lines of a minimum bound in one of the
> LDAPv3 Draft Standard documents.
>
> How about this for a requirement? 
>
> "Implementations MUST support attribute names that are at least 32
> characters in length."


How about 48? If IANA's ub is 48, then implementations could reasonably
expect to see names of that length. All products and implementations
should be prepared to support that.

Further, the requirement should not be limited to attributetype names.
The spec in RFC 3383 covers all object identifier descriptors, which
includes attributetype names, objectclass names, matching rule names,
etc.

How about this?

"Implementations MUST support object identifier descriptors (such as
attributetype names, objectclass names, matching rule names, and the
like) which are at least 48 characters in length."

Larry


> It seems like a simple one without a lot of baggage to me. But if anyone
> thinks there's a good reason not to include it, I'd like to know what
> that is.
>
> I have no strong opinions on an upper bound.
>
> I do realize that there is a work-around for this problem in most cases.
> You can create a shorter attribute name and then use the intended attribute
> name as an alias. But this gets to be a bit complicated when rolling out
> services that use schema designed with longer attribute names.
>
> You have to perform testing to see what each implementation in question
> supports and then create aliases matching up with the shortest supported
> attribute name length.
>
> As a service implementer, that's an awfully expensive interoperability
> hoop to have to jump through if I'm using a technology that is soon to
> be based on a Draft Standard.
>
> I realize that someone might also want a larger attribute name length
> but there seems to already be some restriction with respect to what may be
> allowable from an IANA registration perspective. I'm not questioning that
> because 48 characters for an upper bound seems reasonable to me.
>
> Chris Apple - Principal Architect
>
> DSI Consulting, Inc.
>
> mailto:capple@dsi-consulting.net
>
> http://www.dsi-consulting.com
>
> -----Original Message-----
> From: owner-ietf-ldapbis@OpenLDAP.org
> [mailto:owner-ietf-ldapbis@OpenLDAP.org] On Behalf Of Larry S. Bartz
> Sent: Friday, June 13, 2003 10:48 AM
> To: ietf-ldapbis@OpenLDAP.org
> Subject: Re: Attribute Name Length Bounds
>
>
> Mark C Smith wrote, On 06/13/03 08:26:
>
> > Jim Sermersheim wrote:
> >
> >
> > > As far as I know, neither [Models] nor [Protocol] limits the lenght of
> > > attribute names. Any limitiation in a specific implementation is imposed
> > > by that implementation, not by the spec, so I'm not sure we can do
> > > anything about it here.
> > >
> > > Obviously no server allows an unlimited length, as they are all
> > > limiited if by nothing more than available memory. I'm not sure if this
> > > fits into an implementation report. It seems more appropriate for a
> > > certification/branding program. Other than that, it seems like a valid
> > > defect to raise with those implementors who restrict to unreasonable
> > > limits.
> >
> >
> > I agree. I tried to come up with text that we could add to [Models] or 
> > [Protocols] that would encourage implementors to not impose arbitrary, 
> > short limits... but I am not sure how to word such a requirement so it 
> > is meaningful. This is an interesting interoperability problem though.
> >
> > -Mark
>
>
>
> Perhaps reference to "3.3. Object Identifier Descriptors" of RFC 3383
> "IANA Considerations for LDAP" would be helpful. It says,
>
> "While the protocol places no maximum length restriction upon
>   descriptors, they should be short.  Descriptors longer than 48
>   characters may be viewed as too long to register."
>
> There was obviously consensus in this WG regarding that length and
> that language.