3b. Networks and Communications

Question 1

What is a switch?

Answer 1

A device that connects several devices together to enable communication to take place. You can do things such as limit the bandwidth on certain ports.

Question 2

What is a master switch also called?

Answer 2

Backbone switch.

Question 3

What is a hub?

Answer 3

A hub looks the same as a switch. It is very similar but the data that goes through it isn’t filtered. Data is also more susceptible to interception. Collisions can also occur.

Question 4

What is a WAP?

Answer 4

Wireless access point. A hub that communicates by wireless instead of having physical connections.

Question 5

What is a NIC?

Answer 5

Network interface card. Enable a computer to be connected to a network using a cable. More modern computers have these built in on the motherboard. Each NIC has a MAC so that each card is unique.

Question 6

What does MAC stand for?

Answer 6

Media access control.

Question 7

What is a wireless network interface card?

Answer 7

To connect to a WAP, a device needs a wireless NIC.

Question 8

What is a router?

Answer 8

An advanced version of a switch. Mainly used to connect a LAN to a WAN. Were once used only by big companies, now a household item.

Question 9

What is a repeater?

Answer 9

Signals deteriorate after long cables, so a device is required to extend the range.

Question 10

What is a bridge?

Answer 10

Used to connect two LANs together. It’s similar to a router but it does not store the addresses of devices connected to it.

Question 11

What is a server?

Answer 11

A powerful computer that performs functions on behalf of clients connected to it. There are many different types of server and the size an functionality of a network will dictate how many are needed.

Question 12

What is a file server?

Answer 12

A file server stores files available on the network. It will normally have storage areas set aside for each user on the network that are only accessible to those users.

Question 13

What is an application server?

Answer 13

An application server stores software for use across the network. The application can either be run from the server by a client computer, or the software installation files can be stored on the server so they can be deployed to client computers.

Question 14

What is a disadvantage of an application server?

Answer 14

A lot of network traffic if run from the server. If the installation files are taken from there it requires the clients computer to have the right processor, memory, etc.

Question 15

What is a mail server?

Answer 15

Receives all incoming emails and then allocates them to the appropriate inbox. If the user sends an email it goes to the server and then to somebody else on the LAN/WAN or to the internet. It also filters out spam.

Question 16

What is a proxy server?

Answer 16

Maintain access to the internet within an organisation. Can store cache so websites are quicker to load for other clients. A firewall. Filter access to webpages, so some are blocked.

Question 17

What is a print server?

Answer 17

Manages access to printers within the LAN. Reduces the processing burden on client computers. All print jobs will go in a queue. Can prioritise some in the queue. Can provide reports of who has printed what.

Question 18

What is a back up server?

Answer 18

Backs up all data on a network so that individual users do not have to do it. Usually connected to tape drives. Back up jobs will be scheduled so that they run automatically every day, usually over night.

Question 19

Name 4 types of optical communication methods.

Answer 19

Infrared, fibre, optic and laser.

Question 20

What is infrared?

Answer 20

Only works at short distances, no more than 10 metres. Requires direct line of sight. Bandwidth is restricted to 115.2kbpd.

Question 21

What uses infrared?

Answer 21

Remote controls. Used to be main wireless communication before bluetooth (for phones, laptops, etc.)

Question 22

Describe fibre optics.

Answer 22

Data travels at the speed of light. Used in LANs where distances of more than 100 metres need to be covered. Virgin Media use fibre optics to broadcast cable television signals and to provide broadband.

Question 23

What is laser communication?

Answer 23

Two laser devices in direct line of sight to each other. Each sends and receives a laser beam. Travels at speed of light. Only works in line of sight. Used in laser tag.

Question 24

Name 2 wireless communication devices.

Answer 24

Bluetooth and radio.

Question 25

What is bluetooth?

Answer 25

Range of 10m. Can get applications such as bluetooth headsets for phones, replaced infrared.

Question 26

Advantages of bluetooth?

Answer 26

Widely available, a radio frequency licence is not required, it does not require line of sight, a pass key can be used to prevent non authorised devices from connectong.

Question 27

Disadvantages of bluetooth?

Answer 27

10m range. Can only connect to one device at once.

Question 28

What is radio?

Answer 28

Wi fi. Used to connect to LAN or WANs. Can connect printers via wi fi.

Question 29

Advantages of radio/wi fi?

Answer 29

No need to connect devices using cables, portable devices are not restricted to a particular location for network access, line of sight isn’t required, wi fi standards globally

Question 30

Disadvantages of radio/wi fi?

Answer 30

The range is 30 metres but can be further restricted by walls and steel construction, bandwidth is shared, wireless networks are susceptible to hacking.

Question 31

What is a fax machine?

Answer 31

A 2d document can be fed through the fax and sent electronically via a telephone line to another fax which will print it. Confidentially not safe as anyone could pick it up at other side.

Question 32

Advantages of email:

Answer 32

Send messages to multiple people at once, send attachments, secure due to login required, filter out junk email.

Question 33

What is a bulletin board?

Answer 33

Discuss topics with people (business or pleasure) The discussion board is the whole website, forums are the subjects of discussion and threads are the topics of the discussion. You can subscribe to threads/forums and some users will have public profiles.

Question 34

What is tele/video conferencing?

Answer 34

Allows you to speak to large groups of people. Good for meetings. Can share documents.

Question 35

What is Internet Relay Chat? (IRC)

Answer 35

Sharing ideas with colleagues/social communication. Like Facebook chat. Keeps logs of conversations. The use of emoticons. Multiple people in conversation.