1. Write concurrent TCP client-server programs to simulate a simplified version of POP. The client sends a request to receive an e-mail in its mailbox; the server responds with the e-mail.
2. In SMTP,
a. a non-ASCII message of 1000 bytes is encoded using base64. How many bytes are in the encoded message? How many bytes are redundant? What is the ratio of redundant bytes to the total message?
b. a message of 1000 bytes is encoded using quoted-printable. The message consists of 90 percent ASCII and 10 percent non-ASCII characters. How many bytes are in the encoded message? How many bytes are redundant? What is the ratio of redundant bytes to the total message?
c. Compare the results of the two previous cases. How much is the efficiency improved if the message is a combination of ASCII and non-ASCII characters?