IP Networking

Question 1

What is Encapsulation?

Answer 1

Ecapsulation consists of, for example, an ICMP message that want’s to send a message but which must be wrapped (ecapsulated) in different “letters” to be sent correctly. More information is added. It is wrapped in several layers for each joint, and unpacked when it has reached its destination.

Question 2

How does the Switch know where to send the packets?

Answer 2

It can “shout”. It sends aout a message that says “I want to send a message to 14:fe, is it here?”. If it gets a respond, a new line/brigde is created on the forwarding table.

Question 3

How many classes of subnets are there?

Answer 3

Three!

Class A: 255.0.0.0
Class B: 255.255.0.0
Class C: 255.255.255.0

Question 4

What are Binary numbers?

Answer 4

A binary number is a number expressed in the base-2 numeral system or binary numeral system.

A method of mathematical expression which uses only two symbols: typically “0” (zero) and “1” (one).

Question 5

What are the advantages of classful routing?

Answer 5

Easy and cheap to implement. Fast in hardware. Few routes to store in router memory.

Question 6

What are the disadvantages of classful routing?

Answer 6

Wastes a lot of addresses. If you need 1000 you get 55k.

Question 7

What is CIDR?

Answer 7

Classless InterDomain Routing. No fixed netmasks –> arbitrary variable length netmasks.

Question 8

What are the advantages and disadvantages of CIDR?

Answer 8

Pros: Still fast in hardware. Wastes fewer addresses.
Cons: More routes to store in router memory.

Question 9

What is ARP?

Answer 9

Address Resolution Protocol

Terminal: arping

Question 10

What is UDP?

Answer 10

User Datagram Protocol.

A message oriented protocol, where you can only send small messages. If you need to send a big message you can split it up, but it then may not arrive in order.

• Message oriented
• Multiplexer
• Simple
• Fast
• Stateless (once sent, the OS cant forget it).

Question 11

What is DHCP?

Answer 11

Dynamic Host Configuration Protocol.

The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) networks for automatically assigning IP addresses (and other communication parameters) to devices connected to the network using a client–server architecture.

Question 12

What is the different between ARP and DHCP?

Answer 12

The ARP is host-to-host.
The DHCP is host-to-server.

Both uses broadcast addresses.

Question 13

What is DNS?

Answer 13

Domain Name System.

Uses UDP (user datagram protocol). Translates names into IP.

With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol (IP) network.