Question 1: Distinguish between the two main functions of packet switching networks: forwarding and routing (give the main difference)?

Question 2: Compare between Circuit Switched networks and Packet Switched networks. Identify the appropriate criteria for comparison and then compare.

Question 3: Suppose Host Alice is connected to Host Bob by three routers R1, R2 and R3. Also, suppose that Host Alice wishes to send a large file of 10 MB to Host Bob. The path from Host Alice to Host Bob has four links of rates 1 Mbps, 2 Mbps, 10 Mbps, and 1 Mbps, respectively.

Draw the network architecture described above. Label the hosts, routers and show the link transmission rates.

What is the throughput of the file transfer between host Alice and Host Bob?

By dividing the file size by the throughput (from b), roughly how long will it take to transfer the file from Host Alice to Host Bob?

Assume that the second link between R1 and R2 is shared between the current file transfer and 9 other simultaneous file transmissions, what is the throughput for the current file transfer between Host Alice and host Bob? How long will it take to transfer the file from Host Alice to Host Bob?

Given the propagation speed 3 10⁸ m/s for all four links and distances of links (E-R1) and (R3-Bob) is 1 km while the distance of link (R1-R2) is 20 km and also, the distance between (R2-R3) is 20 km, What is the end-to-end delay for transferring a file of 20 MB?

Assume that an intervening router, R*, is added at the middle of the distance between R1 and R2, what is end-to-end delay for transferring a file of 10MB? What is the effect of adding R* to the network? Explain your answer.

Question 4: Which application layer protocols are stateful and which are stateless? Also, explain what are the advantages and disadvantages of storing states?

Question 5: What type of messages does the HTTP protocol use? Describe the format of these messages and give example messages with their meaning? Does the FTP protocol use exactly the same messages (explain)?

Question 6: Mention the application layer protocols involved in the transmission of an email from the sender user agent to the receiver user agent.

Question 7: Identify the main components of the DNS system and how they are used? Then list two application layer protocols that rely on DNS protocol?

Question 8: What are the main types of network applications architectures? Mention the main differences between these types? What advantage does any type of these architectures have over the others?