The Internet and Socket Programming

Question 1

What started the Internet?

Answer 1

1960s Defense
Advance Research Project Agency created network between research centers

Question 2

When did the Internet become a commercial success?

Answer 2

90s

Question 3

What connects different networks in the Internet?

Answer 3

Routers

Question 4

What connects to a network?

Answer 4

A host

Question 5

What are some examples of hardware to create a network?

Answer 5

Ethernet, Apple Talk

Question 6

Why is IP addressing used?

Answer 6

As an abstraction to hide network internals.

Question 7

How many bits in an IP address?

Answer 7

32

Question 8

What does an IP address represent?

Answer 8

A connection between a computer and a network.

Question 9

Can a computer have multiple IP addresses?

Answer 9

Yes, one for each network connection. (ex: router)

Question 10

What is the prefix in an IP address?

Answer 10

Identifies a network.

Question 11

What is the suffix in an IP address?

Answer 11

Identifies the host of the network.

Question 12

What assigns the prefix for the network and hosts?

Answer 12

Global authority assigns prefix for network, local administrator applies prefix for hosts.

Question 13

How many bits are assigned to the prefix and suffix?

Answer 13

It depends on size of network and number of hosts.

Question 14

What is the subnet mask?

Answer 14

parameter that tells the number of bits used for network number

Question 15

What is the routing table?

Answer 15

Gives the router info to reach the next network.

Question 16

How are routing tables made?

Answer 16

Manually, or automatically through software

Question 17

Does the IP source and destination address of a packet change during transit?

Answer 17

No

Question 18

Does the hardware address of a packet change each forward?

Answer 18

Yes

Question 19

What does Address Resolution Protocol do? (ARP)

Answer 19

Translate IP address to hardware address (ex: ethernet address).

Question 20

What is Domain Name Server?

Answer 20

Translates host names like www.yahoo.com to IP addresses.

Question 21

How were host names translated before DNS?

Answer 21

Through mappings in a file /etc/hosts

Question 22

Can a host have multiple IP addresses?

Answer 22

Yes, if the host has multiple network interfaces.

Question 23

How does DNS work?

Answer 23

lookup algorithm that contacts as many servers as necessary

Question 24

What is Dynamic Host Configuration Protocol?

Answer 24

Allows connecting computers to the Internet without the need of an administration.

Question 25

Before DHCP how did an administrator add a computer to the internet?

Answer 25

◼ The local IP address – Current address ◼ The subnet mask – Used to send packets to hosts in same LAN ◼ The default router – Used to send packets to hosts outside the LAN ◼ The default DNS server – Used to convert names to IP addresses.

Question 26

What is the unix command to set the parameters for pre DHCP connections?

Answer 26

ifconfig

Question 27

What are the two different transport protocols?

Answer 27

User Data Protocol (UDP), and Transmission Control Protocol (TCP).

Question 28

What is UDP best for?

Answer 28

LAN applications.

Question 29

What transport protocol is connectionless?

Answer 29

UDP

Question 30

What identifier ports does UDP have?

Answer 30

Source and Destination applications.

Question 31

What transport protocol is message oriented?

Answer 31

UDP

Question 32

Does TCP have an initial connection?

Answer 32

Yes, unlike UDP

Question 33

What does the TCP Stream Interface look like?

Answer 33

reading and writing to a file

Question 34

How is TCP reliable?

Answer 34

Acknowledgment and Retransmission

Question 35

What is Acknowledgment and Retransmission in TCP?

Answer 35

receiver send acknowledgment signal when packet arrives. sender resends package if timer expires

Question 36

What is the TCP retransmission timer set to?

Answer 36

RTT + 4*RTTSTDDEV

Question 37

What is the adaptive transmission feature of TCP?

Answer 37

The timer of TCP being set.

Question 38

What is the cumulative acknowledgments feature of TCP?

Answer 38

An acknowledgment is for all the bytes received so far without holes and not for every packet received.

Question 39

What is the Fast Retransmission feature of TCP?

Answer 39

It is a heuristic where a duplicated acknowledgment for the same sequence is signal of a packet lost. The data is retransmitted before the timer expires.

Question 40

What is flow control?

Answer 40

sender is slown down if buffer starts to fill

Question 41

What is congestion control?

Answer 41

Slow down retransmission with lost packet

Question 42

How is TCP reliable, be specific.

Answer 42

Three way handshake

Question 43

What cases is UDP used over TCP?

Answer 43

Broadcasting, ex: show all available printers. Real time Data: ex: teleconferencing