A subset of X.500 that can run over TCP/IP networks, LDAP was developed to simplify the demands of the X.500 DAP. Described in the IETF RFCs 1777, LDAP can run as a standalone directory system or can be used as a means of accessing an X.500 directory or other directory. LDAPv3 (RFC 3377) supports non-ASCII and non-English characters for international directories, and can sort through multiple directories on the basis of a single request. See also X.500.