The definition of an attribute type in the schema. LdapAttributeSchema is used to discover an attribute's syntax, and add or delete an attribute definition. RFC 2252, "Lightweight Directory Access Protocol (v3): Attribute Syntax Definitions" contains a description of the information on the Ldap representation of schema. draft-sermerseim-nds-ldap-schema-02, "Ldap Schema for NDS" defines the schema descriptions and non-standard syntaxes used by Novell eDirectory.