Background

X.400 Overview

The X.400 Message Handling System was developed by CCITT and ISO. It was made to satisfy most of the requirements for a complete electronic mail system.

The X.400 protocol covers the following areas:

• Multi-media messages: voice, graphics, fax, text
• Interfacing unlike systems together
• Security of message transmission
• Reliable transport of messages
• Archive of messages
• Directory services - for locating addresses
• Conversion of messages for displaying on terminal or printer.
• Reporting delivery and receipt of messages

X.400 VS. Internet mail

Today, there are two major competitors on the electronic mail standard: MIME & X.400.

Here is a brief list of pros and cons:

• The large base of Internet mail makes MIME a favorite.
• Transition of the current Internet mail to X.400 is very complex.
• X.400 covers many areas, which takes a while to become available. By contrast, Internet products are developed fast.
• MIME is simpler than X.400 - therefore, conformance testing is not required.
• In order to inter-operate the X.400 islands, it must gateway in and out of the Internet. This may cause loss of information.
• X.400 has a security mechanism in transmission of messages. Internet mail provides no such mechanism.
• X.400 implementations often turn out to be incompatible with other X.400 sites.
• MIME can work with normal textual mail without undue complications to the user. This is the bottom-up method: features are added over the existing standard basis.
• The addressing mechanism of X.400 is so large that users use a dictionary instead of typing it.

You can read more about "X.400 vs. The Internet".