Can I have a brief knowledge of different types of traffic?

Traffic is of different types, you can classify them as:

FTP User

Generated when you upload your files to your web account. If you have any FTP sub-accounts, their traffic will be included here, too.

Virtual FTP

Generated when authorized or anonymous internet users download, upload or view files in your virtual FTP directories. If you administer your account through dedicated IP, it will be also added to Virtual FTP Traffic.

Mail

Generated when e-mail messages are sent or received.

HTTP

Generated when internet visitors browse your web site(s).

Real Server FTP

Generated when internet users download media files from your RealServer directory.

Real User FTP

Generated when you upload your media files to your RealServer directory.