Quiz chapter 1, 2, 3 & 8

Question 1

What is a message on the application layer called?

Answer 1

Message

Question 2

What is a message on the Transport layer called?

Answer 2

Segment

Question 3

What is a message on the Network layer called?

Answer 3

Datagram

Question 4

What is a message on the Link layer called?

Answer 4

Frame

Question 5

What is a message on the Physical layer called?

Answer 5

Bits

Question 6

What are all the protocol layers together called?

Answer 6

Protocol stack

Question 7

What does SMTP stand for and what is it used for?

Answer 7

Simple Mail Transfer Protocol
Is used for sending emails

Question 8

What does IMAP and POP stand for and when are they used?

Answer 8

Internet Message Access protocol
and
Post Office Protocol
are used for recieving email

Question 9

What does HTTP stand for and what is it used for?

Answer 9

Hypertext Transfer Protocol
is used to
Transfer Web messages

Question 10

What does DNS stand for and what is it used for?

Answer 10

Domain Name System
is used to
translate domain names to the actual IP-address

Question 11

What does TCP stand for and what is it used for?

Answer 11

Transmission controll protocol
is used for
Reliable unencrypted byte-oriented data stream

Question 12

What does TLS stand for and what is it used for?

Answer 12

Transport layer security
is used for
Reliable encrypted byte-oriented data stream

Question 13

What does UDP stand for and what is it used for?

Answer 13

User Datagram Protocol
is used for
Segments without reliable data transfer

Question 14

Name two service quality guaranties TCP gives

Answer 14

-In-order data delivery
-Reliable data transfer

Question 15

True or false?
When UserDatagramProtocol is used, then any fault correction is up to the application

Answer 15

True!

Question 16

For a TransmissionContolProtocol connection, can the number of unackowledged bytes be larger than the receiver buffer?

Answer 16

No
respect the receiver buffer🙏🏼

Question 17

Do UDP traffic towards the same application in a server use a common socket?

Answer 17

Yessir!
Even if the traffic comes from different clients

Question 18

What is the purpose of nonces in an end-point authentication protocol and in the TLS
handshake?

Answer 18

Defend against connection replay attacks.

Question 19

The acknowledged number (ACK) is cumulative, meaning it can acknowledge more than one received segment

Answer 19

Yes!
the ack number confirms the number of bytes the sender of the message (can be both Client and Server) has received up until now. This ACK number indicates that the other parts (either client or server) Sequence number on the next segment sending should be this number.

Question 20

TCP has a timer waiting for ACK on transmitted segments. What happens if timeout occurs?

Answer 20

The oldest unacknowledged segment is re-transmitted, and timer is re-started.

Question 21

TCP views data as a stream of bits, bytes or messages?

Answer 21

BYTES 🐒

Question 22

TCP sends segments where the sequence number (SEQ) field in TCP header is the sequence number of the first byte in the payload.

Answer 22

Yes
This accounts for both server and client. As the client also need to send some payload to the server during a TCP connection, such as a GET request

Question 23

The client TCP starts the three-way-handshake by sending a SYN request (i.e. a segment with SYN-bit set to 1 often referred to as the phantom-bit).

Answer 23

true 🐥
The client initiates contact with a SYN request
Server responds with at SYN/ACK message
Client confirms the handshake with an ACK message
Contact = TRUE

Question 24

The connection is finally closed when both sides have sent a FIN request and received an ACK response.

Answer 24

YES 🦖
In total 4 TCP messages, 2 FIN requests and 2 ACK responses
Contact = terminated