To fully realize the objectives, email systems will have to converge to use of a single encoding standard which is described in the Future Convergence section below. In the meantime progress towards the objectives can be made by following the current environment guidelines. Very large attached files may hurt the performance and reliability of some email systems. The probability of transmission problems increases with the size of the attached file. The probability becomes significant when the size of the file approaches 1 megabyte.
Some gateways have limitations on the size of transmitted messages.
If a gateway does not transmit the attached file fully and properly, it should return a warning message to the sender. Server administrators should modify their systems to pass on those lines. If a list server enforces a size limitation, a warning message should be send back to the originator. Sender and recipient must be able to use a common protocol. To find a common protocol, see the Email Attached Files Issues and Context document, where you will find a Protocols Interoperability Guide in section 2.1.2.