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RE: Attribute Name Length Bounds



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."

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.

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