Overview#String Representation of Distinguished Names is defined in RFC 4514
In X.500-based directory systems X.500, including those accessed using the Lightweight Directory Access Protocol (LDAP) RFC 4510, Distinguished Names (DNs) are used to unambiguously refer to directory entries X.501RFC 4512.
The structure of a DN X.501 is described in terms of ASN.1 X.680. In the X.500 Directory Access Protocol X.511 (and other ITU-defined directory protocols), DNs are encoded using the Basic Encoding Rules (BER) X.690. In LDAP, DNs are represented in the string form described in RFC 4514.
It is important to have a common format to be able to unambiguously represent a Distinguished Name. The primary goal of RFC 4514 is ease of encoding and decoding. A secondary goal is to have names that are human readable. It is not expected that LDAP implementations with a human user interface would display these strings directly to the user, but that they would most likely be performing translations (such as expressing attribute type names in the local national language).