IT424 – Networks 2
Tutorial_2 (Internet Structure & Application Layer Requirements)
1. Discuss the implications of using packet switching vs. circuit
switching from the end user perspective?
2. Consider an application which transmits data at a steady rate (e.g.,
the sender generates a N bit unit of data every k time units, where k
is small and fixed). Also, when such an application starts, it will
stay on for relatively long period of time. Would a packet-switched
network or a circuit-switched network be more appropriate for this
application? Why?
3. Suppose there is exactly one packet switch between a sending host
and a receiving host. The transmission rates between the sending
host and the switch and between the switch and the receiving host
are R1 and R2, respectively. Assuming that the switch uses storeand-forward packet switching. What is the total end-to-end delay to
send a packet of length L? (Ignore queuing, propagation and
processing delays).
4. During its journey from a source to a destination, a packet may be
lost or may suffer from several delay types. How much time does it
take to transmit a 10 Kbytes-packet from source to destination,
with a physical distance between them of 10^6 m? The
transmission rate is 10 Mbits/s. Assume the propagation speed of
the signal in the transmission medium to be 2*10^8 m/s. (ignore
processing and queuing delay)
5.
In the figure below , if 10 connections (fairly) share backbone
link R. If R = 1 Gb/s, Rs = 7 Mb/s, Rc = 5 Mb/s. What is the per
connection end-to-end throughput?
6. What is the difference between network architecture and
application architecture?
7. What information is used by a process running in one host to
identify a process running on another host?
8. For a communication session between a pair of processes, which
process is the client and which is the server?
9. For a P2P file sharing, do you agree with the statement, “There is
no notion of client and server sides of a communication session”?
Why or why not?
10. Describe an application that requires no data loss and that is also
highly time-sensitive
11. In what way is instant messaging with a centralized index a hybrid
of client-server and P2P architectures?
12. What are the main causes for packet-loss? What do you think
about retransmitting lost packets for interactive voice and video
applications?
13. Why do HTTP, FTP run on top of TCP rather than UDP ?