[x500standard] Re: [T17Q11] Extension markers for attribute syntaxes
- From: "Jean-Paul Lemaire" <jean-paul.lemaire@xxxxxxxxxxxxxxxxxxxxx>
- To: "'Erik Andersen'" <era@xxxxxxx>, "'Directory list'" <x500standard@xxxxxxxxxxxxx>, "'SG17-Q11'" <t09sg17q11@xxxxxxxxxxxxx>
- Date: Sat, 17 Dec 2011 15:24:00 +0100
Hi Erik,
This problem is complex. Since ASN.1 encoding rules provide compatibility
between different versions, a new OID is not needed. In that case a read
operation will give all the components known by the DSA which has retrieved
the data from the Directory and also known by the DUA. In a modify operation
only the components known by the DUA and the DSA master of the naming
context will be taken in consideration. But the DUA cannot be sure that all
requested changes have been applied.
Using a new OID for a new version of the syntax can solve this problem and
also the problem with LDAP using ABNF. But it that case a DUA have to know
the version used by the DSA and in a Directory System all the DSAs can use
different versions of a same attribute. This also adds complexity in
distribution and replication.
Regards
Jean-Paul.
De : Erik Andersen [mailto:era@xxxxxxx]
Envoyé : samedi 17 décembre 2011 10:16
À : Directory list; SG17-Q11
Objet : [T17Q11] Extension markers for attribute syntaxes
I am getting concerned about extension markers in syntax data types. When
an attribute syntax is changed, the attribute type should have a new OID. In
addition, LDAP uses Augmented Backus-Naur Form (ABNF) for defining attribute
syntaxes, except for X.509 ones, where a binary encoding is used. ABNF does
not allow for extension markers. Adding new components to an X.500 attribute
syntax will cause discrepancy between the X.500 variant and the LDAP
variant.
Erik Andersen
Andersen's L-Service
Elsevej 48,
DK-3500 Vaerloese
Denmark
Mobile: +45 2097 1490
e-amail: era@xxxxxxx
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Other related posts:
- » [x500standard] Re: [T17Q11] Extension markers for attribute syntaxes - Jean-Paul Lemaire
