Internet Protocol

Question 1

Which layer does TCP operate in?

Answer 1

layer 4 (transport layer)

Question 2

What does TCP do?

Answer 2

enables reliable, connection oriented communication

Question 3

Which layer does IP sit at?

Answer 3

layer 3 (network layer)

Question 4

What are protocols at layer 3 designed for?

Answer 4

to be routed across multiple heterogenous networks

Question 5

What 2 functions does IP implement?

Answer 5

Addressing
fragmentation

Question 6

What kind of connection is IP?

Answer 6

connectionless protocol

Question 7

What does connectionless mean?

Answer 7

sends packets to another machine but don’t know if packets will arrive or if in correct order

Question 8

What is the internet?

Answer 8

Network of networks of computers

Question 9

why are packets passed between networks?

Answer 9

to reach the destination machine

Question 10

What does the internet need addresses to specify?

Answer 10

the Machine
the network that machine is on

Question 11

Why do we need addresses?

Answer 11

to identify a specific computer so we can send data to it

Question 12

What do addresses in IP need to do?

Answer 12

identify machine uniquely
identify which network machine is on

Question 13

how are IPv4 addresses formatted?

Answer 13

4 bytes seperated by dots
e.g 192.168.1.1

Question 14

Whats the problem with IPv4?

Answer 14

Not enough space to store enough addresses

Question 15

How do we increase the space?

Answer 15

Use IPv6 which increases it to 128 bits

Question 16

How many IP addresses in class A?

Answer 16

16.7 million addresses per network
1.x.x.x to 127.x.x.x

Question 17

How many IP addresses in class B?

Answer 17

65536 addresses
128.0.x.x to 191.255.x.x

Question 18

How many IP addresses in class C?

Answer 18

256 addresses
192.0.0.x - 239.255.255.x

Question 19

What is class D used for?

Answer 19

multicast
224.0.0.0 to 239.255.255.255

Question 20

What is class E used for?

Answer 20

reserved
240.0.0.0 to 255.255.255.255

Question 21

whats the aim of classless inter-domain routing (CIDR)?

Answer 21

to slow ip address space exhaustion

Question 22

what does CDIR do?

Answer 22

allows variable number of bits to be used to identify network
slow rapid growth of routing tables

Question 23

what can address configuration be?

Answer 23

configurable or dynamic

Question 24

What does configurable (static) mean?

Answer 24

you specify IP address

Question 25

What does dynamic mean?

Answer 25

Computer automatically allocated address

Question 26

what is the max size of IP packet on ethernet?

Answer 26

1500 bytes

Question 27

What is the max size of IP packet known as?

Answer 27

Maximum transmission unit (MTU)

Question 28

What is time to live (TTL) field in IPv4 packet used for?

Answer 28

to avoid packets ending up in loop as routes to destination can change at any moment even while packet is in transit

Question 29

How does TTL work?

Answer 29

each router decrements TTL if it = 0 packet is discarded

Question 30

Why are IP packets fragmented?

Answer 30

they are passed between different networks may have different packet sizes

Question 31

How does fragmentation work?

Answer 31

data in IP packet split into chunks these are then sent as IP packets across other network identification field used to identify packet Fragment offset used to specify where data goes Receiver puts fragments back together to regenerate the original packet

Question 32

How big is each chunk?

Answer 32

multiple of 8 bytes long

Question 33

Does IPV6 use fragmentation?

Answer 33

no rather it finds out largest packet size allowed on path between 2 machines then uses as its MTU for sending packets