Avoid sending Large email

 

Henry Wong

During the holiday seasons of Christmas and New Year, CityU had experienced several email jams particularly in the outgoing direction. They were found to be caused by huge email messages blocking the sending queue.

As email is such a handy tool, people are very often tempted to use it to send almost everything, say computer files of graphical images, word-processor documents, audio/video data, or even computer software and operating systems - sometimes of size as large as several to tens of megabytes!

However, the result may be disastrous! When despatching large email, if there is any instability with the Internet connection, the transmission will be interrupted and the system will have to try sending the email again and again. This will certainly cause unnecessary loading on the network traffic and, in the most undesirable case, even the whole email system would be affected. This situation is particularly obvious when the receiving side is a distant country, or worse if the Internet connection to the destination is unstable, say for some remote provinces in the mainland China.

It is therefore recommended to avoid sending large files via email. There is no magic number to quantify "large" since, as explained earlier, it depends on the Internet traffic and network stability on both ends. For example, it may be fine to send a 2 Megabytes file to New York in USA but not the same file to the mainland China. We would thus advise users not to send a single file larger than 2 Megabytes. Actually there are several alternatives as listed below for you to mail large files:

1. Use FTP (File Transfer Protocol) which is a common tool for transfer of files over the Internet. Since FTP can run on many computer platforms, it is the ideal choice if you and your recipient have different computing environments. Since FTP is an interactive tool, you can see what is going on during the file transfer process. If interruption occurs, the problem causing it can be identified and re-transfer can be initiated at once, if desired.
   
2. Split the original file into several smaller files and send them in separate mail. This method is most suitable for sending material that can be broken down and put together, say based on page number, chapter, section and the like.
   For large files or files containing audio/video data or software, it would be difficult to break them down manually. Luckily there are tools such as UUDEVIEW which can ease the breaking and joining processes. These tools also help minimize the file size, hence improving the sending performance. However, one thing you should confirm before using these tools is to make sure that your recipient has the same tool to put the mail together to reclaim the original file.
   
3. Backup or copy the files on to floppy diskettes and send them by post. If the Internet connect is so unstable at the receiving side, you might need to use this method. But be reminded if you use the 3.5" floppies, make sure they are virus free, and pack them properly so as to avoid bending or damage during the posting process.

If you need more assistance on the above, please contact our Hotline at ext.7658, or email to cc@plink.cityu.edu.hk.

Computing Services Centre City University of Hong Kong ccnetcom@cityu.edu.hk