Copyright 2000-2021 Intelligent Networking Laboratory

Sungkyunkwan University

Review Questionnaires:Chapter 2. Application Layer + Chapter 3.

Transport Layer (Protocols in Transport Layer)

Computer Networks

Sungkyunkwan University

Prepared by Vi Van Vo and Hyunseung Choochoo@skku.edu

Computer Networks Intelligent Networking Laboratory 2/11

Problem 1 Which of the following Email protocol(s) is used for retrieving emails?

What are the full names of these protocols?

A. MIME

B. SMTP

C. IMAP4

D. POP3

Computer Networks Intelligent Networking Laboratory 3/11

Problem 2 Answering True/False about HTTP:

A. HTTP/1.0 uses persistent connections

B. HTTP/1.1 relies on TCP so it must establish handshaking process for every

request

C. HTTP/2 reduces the latency by using UDP protocol which allows multiple

streams onto a single UDP connection

D. HTTP/3 integrates a transport layer protocol – QUICK in application layer

instead of using it from the Transport layer (like Previous HTTP versions do)

Computer Networks Intelligent Networking Laboratory 4/11

Problem 3 DNS Resolution: Assuming a host request an IP address of the domain

name monet.skku.edu. At steps 2 and 3, assume that the Root serverdoes not have the IP address the host wants, where does the next querygo to? What kind of DNS resolution is this?

1

8

2

3

45

6 7

Top-leveldomain server

?

?

SKKU Network

dns.skku.edu

monet.skku.edu

dns.anet.edu

Computer Networks Intelligent Networking Laboratory 5/11

Problem 4 Can you select two statements that are NOT TRUE about Peer-to-Peer

(P2P) paradigm?A. Highly scalability, increase service capability

B. Arbitrary end systems directly communicate

C. Easy to manage

D. No always-on server

E. Peers are intermittently connected and change their IP address

Computer Networks Intelligent Networking Laboratory 6/11

Problem 5 Answering True/False in Kademlia:

A. Using NOR to calculate the distance between two keys

B. Using XOR to calculate distance between two nodes

C. Assume that N4, N7 and N11 are three active nodes, then key k8 is

stored in N11

Computer Networks Intelligent Networking Laboratory 7/11

Problem 6 In a Kademlia network, the identifier space is 256. Compute the

following:

A. What is the number of leaf nodes?

B. What is the number of rows, columns in each routing table?

C. What is the number of subtrees that each node has?

D. What is the height of the tree?

Computer Networks Intelligent Networking Laboratory 8/11

Problem 7 Which statements are True/False about Socket Interface?

A. There are five fields used in socket address structure

B. In TCP communication, because the server uses two different sockets –

listen socket and socket, it creates both sockets for connection

establishment

C. In UDP communication, a server can serve multiple clients simultaneously

D. TCP communication can be iterative (serving a client at a time) or

concurrent (serving several clients at a time)

Computer Networks Intelligent Networking Laboratory 9/11

Problem 8 Find the successors for the following keys

Computer Networks Intelligent Networking Laboratory 10/11

Problem 9 Fill in blanks these statements about Transport layer services:

A. Client process has the …………………… port number

B. Server process has the …………………… port number

C. Encapsulation happens at the …………… site and decapsulation happens at

the …………… site

D. After the host has been selected, the …………… defines one of the processes

on this particular host

E. Socket address: the combination of a(n) ………… and a(n) ……………

Computer Networks Intelligent Networking Laboratory 11/11

Problem 10 Classify the following statements into Flow/Error/Congestion control

A. Managing the rate of data transmission between producer and consumer to

prevent losing the data items at the consumer site

B. Keeping track of lost and discarded packets and resending them

C. The load on the network is greater than the capacity of the network

D. Recognizing duplicate packets and discarding them

Copyright 2000-2021 Intelligent Networking Laboratory

Sungkyunkwan University

Thanks to contributors

Mr. Vi Van VoProf. Hyunseung Choo