It should also explain that "string" encoding does not have to be a printable value. So an attribute with an Octet String syntax can be transmitted as a string where the value is the sequence of bytes comprising its value (without the binary option and without the ASN.1 OCTET STRING tag). Section 4.1.6 implies this but it would be clearer if it said "Attribute string syntaxes may be defined which have arbitrary or non-printable syntax".
There's definitely a terminology problem in this issue. We say binary when we really mean "ASN.1 encoded" and we say string when we really mean "ldap syntax".
-----Original Message-----
From: Salter, Thomas A [mailto:Thomas.Salter@unisys.com]
Sent: Thursday, January 18, 2001 9:25 AM
To: Kurt D. Zeilenga
Cc: ietf-ldapbis@OpenLDAP.org
Subject: RE: AttributeTypeValue and binary
I agree. I especially want to see the explanation that "binary" means "BER
encoding of an ASN.1 data type" included in the first reference to the
binary option. First-time readers tend to think that binary means JPEGs and
other non-printable things.
> -----Original Message-----
> From: Kurt D. Zeilenga [mailto:Kurt@OpenLDAP.org]
> Sent: Wednesday, January 17, 2001 4:21 PM
> To: ietf-ldapbis@OpenLDAP.org
> Subject: AttributeTypeValue and binary
>
>
> RFC 2251, 4.1.6:
> A field of type AttributeValue takes on as its value
> either a string
> encoding of a AttributeValue data type, or an OCTET
> STRING containing
> an encoded binary value, depending on whether the
> "binary" option is
> present in the companion AttributeDescription to this
> AttributeValue.
> AttributeValue ::= OCTET STRING
>
> This wording can be interpreted as either:
> A field of type AttributeValue is an OCTET STRING which contains
> either a string encoding of a AttributeValue data type or an
> binary encoded value depending on whether the "binary" option is
> present in the companion AttributeDescription to this
> AttributeValue.
>
> or:
> A field of type AttributeValue is an OCTET STRING which contains
> either a string encoding of a AttributeValue data type or an
> OCTET STRING containing an binary encoded value depending on
> whether the "binary" option is present in the companion
> AttributeDescription to this AttributeValue.
>
> RFC 2252, 4.3.1 provides clarification that the correct
> interpretation
> is the former. I think RFC 2251 should be clarified to remove any
> doubt.
>
> Actually, I suggest that the description of the "binary" transfer
> option be described completely within (and only within) RFC 2251
> and that "binary" syntax be described within RFC 2252.
>
> Also as previously noted on the LDAPext mailing list (see archives
> for discussion), "binary" transfer of values of "binary" syntax
> makes little sense and likely should be disallowed.
>
> Comments?
>