Week 4

Question 1

What are the four methods of network addressing?

Answer 1

• Data link layer MAC (Media Access Control) address
• Network layer IP (Internet Protocol) address (used to find any computer in the world)
• Transport layer port numbers are used to find applications
• Application layer FQDNs, computer names, and host names

Question 2

What are the two parts of a MAC address?

Answer 2

• OUI (Organizationally Unique Identifier) is the first 24 bits (or manufacturer-ID)
• Extension identifier is the last 24 bits (or device ID)

Question 3

What is an IPv4 address?

Answer 3

An IPv4 address is a 32 bit address that is organised into four groups of 8 bits each (known as octets). There are 5 classes of IPv4 (A - E). Each of the 4 octets can be any number from 0 to 255. Some IP addresses are reserved

Question 4

What classes of IPv4 addresses are available for use on the internet? (i.e. Public IP addresses)

Answer 4

Classes A, B, and C

Question 5

What is classless addressing in relation to IPv4 addresses

Answer 5

Classless addressing allows the dividing line between network and host portions to fall anywhere along the string of binary bits in an IP address

Question 6

What is CIDR notation in relation to IPv4 addresses

Answer 6

CIDR (Classless Inter-Domain Routing) notation takes the network ID and follows it with a forward slash followed by the number of bits that are used for the network ID

Question 7

What is NAT in relation to IPv4 addresses?

Answer 7

Network Address Translation (NAT) is a process where a gateway device substitutes the private IP addresses with its own public address

Question 8

What is PAT?

Answer 8

Port Address Translation (PAT) is the process of assigning a TCP port number to each ongoing session between a local host and Internet host

Question 9

What are the two variations of NAT?

Answer 9

1. SNAT (Source Network Address Translation) - the gateway assigns the same public IP address to a host each time it makes a request to access the internet.
2. DNAT (Dynamic Network Address Translation) - the gateway has a pool of public addresses that are free to assign to a local host when it makes a request to access the internet

Question 10

What is an IPv6 address?

Answer 10

An IPv6 address has 128 bits written as eight blocks of hexadecimal numbers separated by colons with each block being 16 bits.

Question 11

What does IPv6 term “link” mean?

Answer 11

A link is any LAN bounded by routers

Question 12

What does IPv6 term “neighbours” mean?

Answer 12

Neighbours are two or more nodes on the same link

Question 13

What does IPv6 term “Tunnelling” mean?

Answer 13

Tunnelling is a method used by IPv6 to transport IPv6 packets through or over an IPv4 network

Question 14

What does IPv6 term “Interface ID” mean?

Answer 14

Interface ID is the last 64 bits or four blocks of an IPv6 address that identify the interface

Question 15

What are the three types of IPv6 address?

Answer 15

1. Global address - can be routed to the internet
2. Link local address - can be used for communicating with nodes in the same link
3. Loopback address - can be used to test an interface and supporting protocol stack are functioning properly

Question 16

What is a port?

Answer 16

A port is a number assigned to a process that can receive data. Port numbers ensure data is transmitted to the correct process among multiple processes running on a single device

Question 17

What is an FQDN?

Answer 17

A fully qualified domain name is the full name of a host (e.g. www.google.com). The last part of an FQDN is called the top-level domain (TLD)

Question 18

What is a URL?

Answer 18

A URL (uniform resource locator) is an address that identifies where to find a particular resource on a network

Question 19

What is name resolution?

Answer 19

Name resolution is the process of discovering the IP address of a host when you know the FQDN

Question 20

What is DNS?

Answer 20

DNS is an Application layer client-server system of computers and databases made up of these elements:
- Namespace - all computer names and their associated IP addresses stored in databases on DNS name servers around the globe
- Name servers - hold databases, which are organised in a hierarchical structure
- Resolvers - a DNS client that requests information from DNS name servers

Question 21

What are Class D IP addresses used for and what range are they in?

Answer 21

Class D IP addresses are not allocated to hosts and are used for multicasting. They have a range of 224.0.0.0 to 239.255.255.255

Question 22

What are Class E IP addresses used for and what range are they in?

Answer 22

Class E IP addresses are not allocated to hosts and are not available for general use. These are reserved for research purposes. They range from 240.0.0.0 to 255.255.255.255

Question 23

What are Class A IP addresses used for and what range are they in?

Answer 23

Class A IP addresses are used for networks with a large number of total hosts. They range from 1.0.0.0 to 127.0.0.0. Supports 126 networks and approximately 17 million hosts per network

Question 24

What are Class B IP addresses used for and what range are they in?

Answer 24

Class B IP addresses are used for medium to large sized networks. They range from 128.0.0.0 to 191.255.0.0. Supports 16,384 networks and 65,000 hosts per network

Question 25

What are Class C IP addresses used for and what range are they in?

Answer 25

Class C IP addresses are used in small local area networks. They range from 192.0.0.0 to 223.255.255.0. Supports approximately 2 million networks and 254 hosts per network.