Chapter Six: Computer communications and networking.

Question 1

Describe the purpose of an NIC.

Answer 1

The NIC is a physical device that generates and receives suitable electrical signals. It can also carry out simple addressing by making use of MAC.

Question 2

Distinguish between a network hub and a network switch.

Answer 2

Network hubs are hardware devices that connect many network devise together making them work in a network segment. They have a number of input and output ports which connect to each other. Network switches connect network segments or devices. They can also act as bridges, which connect more than one network, allowing them to function as one network. A switch differs from a hub by transmitting a message only to the device intended instead of to all connections.

Question 3

State three ways in which security can be implemented on a wireless access point.

Answer 3

Encryption
Hiding their broadcast identities
Allowing access to only certain MAC addresses.

Question 4

Describe the purpose of a router.

Answer 4

A router receives in the form of packets and forwards them to their destinations which is often another router. Routers direct traffic through large networks, notably the internet.

Question 5

What is a network bridge?

Answer 5

A network bridge connects more than one network, allowing them to function as one network.

Question 6

State three uses for a network server

Answer 6

Database server: Stores the co-operate database.
File server: Which stores user files.
Mail server: Which stores emails received and sent.

Question 7

Explain the difference between a client-server network and a peer-to-peer network.

Answer 7

In a peer-to-peer network, all computers are equal. Each computer serves the needs of the user as well as carrying networking functions. Whereas, in a client-server network, one or more servers provide services to many client machines where the users work.

Question 8

Explain why bus topologies can be slow.

Answer 8

Bus topologies can be slow because there can be many data collisions which slow down the network.

Question 9

State two advantages of a star network over a bus network.

Answer 9

A star topology is robust, so there are fewer problems. A problem with the connection does no affect the whole network. Also, there are fewer data collisions than a bus topology, so the star topology is faster.

Question 10

Explain what is meant by a network protocol.

Answer 10

A set of rules that cover data communications is called a protocol.

Question 11

Describe two protocols commonly used on the internet.

Answer 11

TCP/IP

Question 12

What is a data packet?

Answer 12

Packets are collections of data forming part of a message. A packet is constructed according to rules laid down by the appropriate protocol.

Question 13

What is an IP address?

Answer 13

An IP address is a 32-bit number. Each group of eight bits is called by an octet. Each octet can stores numbers ranging from 0 to 255.

Question 14

What is a MAC address?

Answer 14

MAC means Media Access Control. A MAC address is a unique number stored in each NIC so it can be used to identify a device on a device on a network.

Question 15

Identify three ways in which a catastrophic data loss can occur.

Answer 15

Data loss by deliberate or accidental deletion;
Theft of data which might not even be apparent if copied;
Installation of malware.

Question 16

What needs to be taken into account when deciding on the frequency of taking network backups?

Answer 16

Backups should be done often enough that the business can continue to function as quickly as possible after a data loss incident and that no data is lost that cannot be recreated.

Question 17

What is the difference between a backup and an archive?

Answer 17

A partial backup is sometimes enough, where the backup is only of data that has changed since the last backup. The archive flag of a file is set after a backup has been done and it is cleared If the data is changed. This allows automatic partial backups to take place.

Question 18

What does the term ‘Failover’ mean?

Answer 18

A failover is when the software detects a potential disaster or abnormality and immediately transfers operations to a duplicate system.

Question 19

Describe how a network authenticates a user.

Answer 19

In many systems, the users are members of groups such as finance or personnel. Permission can be assigned separately to an individual, a group or anyone else such as a guest user.

Question 20

State three characteristics of a strong password.

Answer 20

Make it long enough.
Include numbers and letters.
Include special characters.

Question 21

State three sensible conditions of an acceptable use policies.

Answer 21

Not using the network for bulk mailings or marketing;
Not accessing unauthorised materials;
Not wasting staff time.

Question 22

Explain what a DSL connection is.

Answer 22

Digital subscriber line routers are combined with a modem in order to make use of unused bandwidth in the telephone line which connects with internet links at the telephone exchange.

Question 23

What is the purpose of a modem?

Answer 23

Modem (Modulator-Demodulator) converts between these signals and allows connection to the internet on the POTS (Plain Old Telephone Service) which is still widespread.

Question 24

Distinguish between lossy and lossless compression.

Answer 24

Lossy compression works by removing some of the data from the file. The data is removed cannot be recovered. Lossy compression is used in file formats such as MP3, JPG and MPEG. Whereas lossless compression does not store repeated detail, such as lots of pixels in a photo that includes the sky. It allows the original file to be reconstructed exactly.

Question 25

Explain the importance of file standards when including external files on a web

Answer 25

Firstly, it saves space on media and also reduces transmissions times on a network, especially the internet.