EMSD Design Goals and Requirements

The EMSD protocols have been designed to accomplish three high-level goals:

1. Define the new "world" of Efficient Mail Submission & Delivery
2. Define a remote operations service that can handle messaging and other standard networking applications
3. Make EMSD an extension of the existing Internetworking world

Based on these goals, EMSD has been designed to satisfy the following design requirements:

1. Support the submission of short mail messages with the same (or better) level of functionality as the existing Internet mail protocols.

2. Support the delivery of short mail messages with the same (or better) level of functionality as the existing Internet mail protocols.

3. Function as an extension of the existing mainstream Internet mail.

4. Minimize the number of transmissions.

5. Minimize the number of bytes transmitted.

6. Be quick: minimize the latency of message submission and delivery.

7. Provide the same level of reliability (or better) as the existing e-mail protocols.

8. Accommodate varying sizes of messages: the size of a message may determine how the system deals with the message, but the system must accommodate it.

9. Be power efficient and show respect for mobile platform resources, including memory and CPU levels, as well as battery power longevity. In other words, be client-light and server-heavy.

10. Be highly extensible. Different users will demand different options, so the solution cannot require every feature to be a part of every message. Likewise, usage will emerge that is not currently recognized as a requirement. The solution must be extensible enough to handle new, emerging requirements.

11. Be secure. Provide the same level of security (or better) as the existing e-mail protocols. Content confidentiality, originator/recipient authentication, and message integrity must be available options to users.

12. Be easy to implement: re-use existing technology as much as possible.

The EMSD protocols make extensive use of existing technology, including:

• RFC-822
• ASN.1
• Basic Encoding Rules
• Internet mail

By using these established technologies, the design of EMSD avoids the expense and other problems associated with "re-inventing the wheel." The above technologies have been thoroughly tested, and have proven to be reliable solutions for the problems they address (e.g. message format, reliable message delivery, encoding and compacting). The EMSD specifications cater to users who enjoy the advantages of this new technology, but at the same time want to be connected to the rest of the existing Internet e-mail world. Figure 6.3 shows how the Global and EMSD worlds complement one another.

The Internet e-mail community is shown in the lower half of the figure. This world is connected to the EMSD Internet e-mail system.

Figure 6.3: EMSD World and Global Messaging World