Describe in brief how email system works

Following is a simple description of how email system works:

-  Sender composes a message (and attaches a file if required) and sends it

-  This message is sent to an ISP (Internet Service Provider) mail server

-  Mail server examines address associated with message and decides how to route message

-  Message travels over the internet arriving at recipient's ISP mail server

-  Message is then held in the recipient's electronic mail box

-  To read the message, recipient logs on to their mail server

-  Message is then retrieved and sent to recipient's computer