This illustration shows the AQ client, which is connected to the Oracle e-mail server by a double-headed arrow. The double-headed arrow is labeled "XML Message over SMTP." An arrowhead leads from the Oracle e-mail server to the LDAP server. The Oracle e-mail server is also connected to the Web server, which contains the AQ servlet, by a double-headed arrow. An arrowhead leads from the Web server to the Oracle9i server, which contains the AQ queue.