Layers and Protocols

Question 1

What are the five main layers within TCP/IP

Answer 1

Application, Physical, Internet, Network, Data Link

Question 2

What is the physical layer ?

Answer 2

This layer is at the bottom of the stack and is pure hardware including the cable or satellite connection medium and the network interface card. The physical layer transforms data into bits that move across the network media.

Question 3

What is the data link layer ?

Answer 3

This is where the MAC address gets used. If the layer is sending it adds it source and destination MAC address to the frame. On receiving a frame this layer reads the destination MAC address and if it corresponds to the MAC address on its NIC cards will send it up the higher levels.

Question 4

What is the internet layer ?

Answer 4

This is where the IP address is used

Question 5

What is the transport layer ?

Answer 5

This the layer that ensures that the packets have no errors and that all packets arrive and are re-assembled in the correct order. The two protocols are TCP and UDP. UDP does no error checking

Question 6

What is the application layer ?

Answer 6

Converts the packets into the right format for the application.

Question 7

What is ARP ?

Answer 7

Address Resolution Protocol - Responsible for finding out a computers NIC hardware address for the MAC address.

Question 8

What is the Reverse Address Resolution Protocol ?

Answer 8

Allows discovery of an IP address when you only have an IP address

Question 9

What is ICMP ?

Answer 9

Internet Control Message Protocol - Offers ping functionality

Question 10

What is IPSec ?

Answer 10

IP Security Protocols - Encryption standard used in VPNs. IPSec also confirms that the computer joining the VPN is a valid member of the network.

Question 11

What is L2TP >

Answer 11

Layer 2 Tunneling Protocol uses IPSEC to encrypt traffic through VPN tunnels

Question 12

What is the role of TCP

Answer 12

Error Checking and Sequence Numbering

Question 13

How does the TCP protocol exist

Answer 13

It establishes a connection after the data has arrived at the IP address to establish the sequencing.

Question 14

What is UDP ?

Answer 14

Similar to TCP but without the error checking and sequencing. It is a connectionless protocol designed to get data to the applications as fast as possible.

Question 15

What are the example applications that use UDP?

Answer 15

Voip, DNS, NFS

Question 16

What are the roles of the routing protocols ?

Answer 16

To move data between networks

Question 17

What is BGP routing protocol ?

Answer 17

Keeps track of the network numbers that connect the internet

Question 18

What is the Open Shortest Path First routing protocol?

Answer 18

Calculates and alternative route that the packet should follow when a path fails. It is also known as dynamic routing.

Question 19

What is the DNSSEC protocol ?

Answer 19

A secure extension of the DNS protocol

Question 20

What is the NTP protocol?

Answer 20

Network Time Protocol - You can use it to keep network clocks in sync by retrieving data from a time server computer

Question 21

What is the DHCP protocol?

Answer 21

Mechanism for requesting an IP address it is a client server model