hw1 - CS 168 Computer Networks Jannotti Homework 1 Due 20...

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CS 168 Computer Networks Jannotti Homework 1 Due: 20 February 2010, 4pm Problem 1 Section 2, problems 2, 4, 29, 39 Problem 2 Section 3, problems 3, 4, 15, 16 Problem 3 Consider an e-mail system, in which an e-mail client is used to send messages to the e-mail server. You are the head programmer for this project. You want to make sure that if the e-mail client tells the user that the e-mail is sent, the server has received the e-mail message. Unfortunately, after spending many years on socket programming, you know that the socket API itself does not provide this functionality as is. When you call a socket write on the e-mail message, even if a blocking
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Unformatted text preview: write call returns with no error, it does not mean that the server has received the message. Propose a solution at the user-level (without modifying the transport layer and below, only at the application layer) that ensures that the e-mail client does not provide an “e-mail sent” message before the server possesses the message, and each message is sent only once. Consider the fact that a con-nection may be dropped, causing a socket to close pre-maturely. Elaborate on your choice of UDP/TCP as the transport layer in your solution, and issues like re-transmission....
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