Topic #11: The Network Layer

Question 1

It is the layer that provides services to exchange data over the network between end devices

Answer 1

Network Layer

Question 2

Differences between the Network and Transport Layer

Answer 2

Transport layer connects processes while Network Layer enables devices to reach each other

Question 3

4 Processes in the Network Layer

Answer 3

Addressing
Encapsulation
Routing
Decapsulation

Question 4

Functions of the Network Layer

Answer 4

• receives segments of data from the transport layer
• uses protocols to add addressing information and other information and send it along the best path

Question 5

Function of Network Layer Protocols

Answer 5

• shares upper-layer information between hosts
• specifies the addressing and packaging of a transport layer and describe how the PDU is to be carried with minimum overhead

Question 6

Network Layer tasks to be performed

Answer 6

• Addressing packets with an IP address
• Encapsulation of Packets
• Routing of Packets
• Decapsulation of Packets

Question 7

Devices in IP networks that have IP addresses

Answer 7

Hosts

Question 8

IP address of the sending host

Answer 8

source IP address

Question 9

IP address of the receiving host

Answer 9

destination IP address

Question 10

This contains the address information and some other bits that identify the PDU as a network layer PDU

Answer 10

IP headeer

Question 11

The process of adding the address information to the data

Answer 11

Encapsulation

Question 12

When a level 4 PDU has been encapsulated what is it referred to?

Answer 12

Packet

Question 13

It is the process routers perform when receiving packets, analyze address information, use the address information to select a path for the packet and forward it to the next router

Answer 13

Routing

Question 14

Each route that a packet takes to reach the next device

Answer 14

Hop

Question 15

It is the process of removing encapsulation data at different layers

Answer 15

Decapsulation

Question 16

Where does the IP packet decapsulated

Answer 16

at the Final destination

Question 17

Network Layer protocols

Answer 17

IPv4
IPv6
Novell IPX
AppleTalk
Connectionless Network Service

Question 18

It is the most widely used network protocol

Answer 18

Internet Protocol version 4

Question 19

It is an network layer protocol that will work with IPv4 and will likely to replace it

Answer 19

IPv6

Question 20

A Widely popular internetworking protocol in the 1980s and 1990s

Answer 20

Novell IPX

Question 21

Apple Computer’s proprietary networking protocol

Answer 21

AppleTalk

Question 22

it is a common networking protocol used in telecommunication networks that does not require established circuits

Answer 22

Connectionless Network Service

Question 23

Characteristics of IPv4

Answer 23

• Connectionless - receiving host is NOT contacted before the message is sent
• Best Effort - IP does not have the capability to manage and recover, missing and corrupt packets
• Independent - operates independently of the medium carrying the data

Question 24

Key fields in an IPv4 Header

Answer 24

IP Source Address
IP Destination Address
Time to Live
Type of Service
Protocol
Flag and Fragment Offset

Question 25

This IPv4 key field contains the host that will send the packet

Answer 25

IP Source Address

Question 26

This IPv4 key field contains the host that will receive the packet

Answer 26

IP Destination Address

Question 27

This IPv4 field describes the maximum hops a packet can take before it is considered "lost" or undeliverable

Answer 27

Time to Live

Question 28

This IPv4 field describes the level of throughput priority a router should use in processing a packet

Answer 28

Type of Service

Question 29

This IPv4 field describes upper-layer protocol

Answer 29

Protocol

Question 30

This IPv4 field describes whether to fragment a packet when forwarding it from one medium to another

Answer 30

Flag and Fragment Offset

Question 31

This IPv4 field describes whether it is version 4 or 6

Answer 31

Version

Question 32

This IPv4 field describes how long the header is

Answer 32

Internet Header Length

Question 33

This IPv4 field helps reassemble any fragments

Answer 33

Identification

Question 34

This IPv4 field describes the length of the header

Answer 34

Header Checksum

Question 35

This IPv4 field used rarely to provide special routing services

Answer 35

Options

Question 36

This IPv4 field is used when header does not end on a 32-bit boundary

Answer 36

Padding

Question 37

Basis to divide networks

Answer 37

*Purpose - users with similar software and bandwidth needs are grouped together *Ownership - users that help in controlling access, administration and security are grouped together Geographic Location - users that are in the same location are grouped together

Question 38

Reasons to Separate Hosts in a Network

Answer 38

- Increase performance - Better Security - Better address management