Network layer

Question 1

What is the networking device operating on network layer?

Answer 1

A router

Question 2

What is the protocol used on the network layer?

Answer 2

Internet Protocol, IPv4 and IPv6

Question 3

What is the unit of data in network layer called?

Answer 3

An IP packet

Question 4

What do routers do?

Answer 4

Interconnect different LAN’s and forward IP packets based on the destination IP address in the IP packets header field.

Question 5

How long are IPv4 addresses?

Answer 5

32 bits, divided into four groups of 8 bits

Question 6

How long are IPv6 addresses?

Answer 6

128 bits, divided into 8 groups of 4 hexadecimal numbers

Question 7

How big is the interface ID (host portion) of IPv6 address?

Answer 7

64 bits

Question 8

How big is the host portion of an IPv4 address?

Answer 8

It depends on how long the network part is, defined by the subnet mask

Question 9

How the network portion and the host portion are split from the IP address?

Answer 9

Using a subnet mask and bitwise AND. Subnet mask defines the length of the network portion.

Question 10

If IPv4 address has /24 in the end, what does it mean?

Answer 10

That the network address is the first 24 bits of the 32-bit address.

Question 11

How are IP packets prevented from circulating endlessly in networks?

Answer 11

Time To Live field in packet header defines how many hops it can travel before being dropped. In IPv6 TTL is replaced by Hop Limit but it works similarily

Question 12

What is VLSM Subnetting and what are it’s benefits?

Answer 12

VLSM stands for Variable Length Subnet Mask and it enables to split a network into different sized subnets. You can reduce the number of wasted address spaces by using VLSM

Question 13

Name 3 different IP networking troubleshooting tools.

Answer 13

ping, traceroute, ipconfig/ifconfig, nslookup, netstat, wireshark, nmap, netcat