section 2

Question 1

what is a LAN?

Answer 1

a local area network

Question 2

facts about a LAN ?

Answer 2

• covers a small geographical area located on a single site
• all the hardware for a LAN is owned by the organisation that uses it
• LANs (ethernet) are either wired or wireless (wif-fi)

Question 3

advantages of LANs?

Answer 3

• sharing files is easier, network users can accesses the same files and work collaboratively
• you can share the same hardware, such as printers,
• internet conncetion can be shared between every device on the LAN
• can install and update software on all computers at once
• user accounts can be stored centrally

Question 4

what is a WAN?

Answer 4

a wide area network

Question 5

facts about WANs?

Answer 5

• a WAN connects LANs that are in different geographical locations
• unlike a LAN, organisations hire infrastructure from telecommunications companies, who own and manage the WAN, because a WAN is more expensive to setup the a LAN
• can be connected using fibre or optic telephone lines/satellite links/radio links
• the internet is one big WAN

Question 6

what is bandwidth?

Answer 6

the amount of data that can be transferred in a given time, the greater the bandwidth the greater the network can perform

Question 7

issues and solutions with bandwidth?

Answer 7

• available bandwidth is shared between users of a network
• too many users or heavy use may cause congestion and slow the network
• you can limit the bandwidth available to individual users to address this

Question 8

other factors affecting a network’s performance?

Answer 8

• wired connections generally faster and more reliable than wireless
• fibre optic cables can give much better performance than copper cables
• choice of hardware other than cables and network topology

Question 9

factors affecting wireless connection?

Answer 9

• depends on the signal quality so is affected by the range of the device
• the amount of interference from other devices
• physical obstructions like thick walls in buildings

Question 10

3 times of hardware needed for a network?

Answer 10

NIC, Switch, Router

Question 11

what is a network interface controller (NIC)?

Answer 11

• an internal piece of hardware that allows a device to connect to a network
• exist for both wired and wireless connections

Question 12

what is a Switch?

Answer 12

• connects devices on a LAN

- receive data from one device and transmit this data to the device on the network with the correct MAC address

Question 13

what is a router?

Answer 13

• responsible for transmitting data between networks
• always connected to at least two different networks
• have a crucial role on the internet, directing data in packets to their destination
• used in offices and homes to connect LANs to the internet

Question 14

types of ethernet cables used to connect devices on a LAN and WAN?

Answer 14

• CAT 5e and CAT 6, 4 pairs of copper wires twisted together to reduce internal interference
• coaxial cables are a single metal wire surrounded by a plastic layer for insulation and a metallic mesh which provides shielding from outside interference
• fibre optic cables, transmit data as light, they are high performance cables: they don’t suffer interference and can transmit over very large distances without loss of signal

Question 15

what do wireless networks use to transmit data?

Answer 15

radio waves

Question 16

what do you need to setup a wireless network?

Answer 16

-a WAP (wireless access point) - a switch that allows devices to connect wirelessly

Question 17

what are hotspots?

Answer 17

locations where you can connect to a WAP

Question 18

to connect to a network devices need?

Answer 18

• wireless capability
• devices that don’t can still connect using a dongle
• dongles come in the form of USB dongles and HDMI dongles

Question 19

what are the two radio frequency bands wi-fi uses?

Answer 19

2.4 GHz and 5 GHz

Question 20

how do wi-fi frequency bands work?

Answer 20

the bands are split into numbered channels, each cover a small frequency range, the channels in 2.4 GHz overlap

Question 21

how is wi-fi perfomance affected?

Answer 21

• by interference between networks using adjacent channels

- the frequency band a network uses

Question 22

advantages of 2.4 GHz?

Answer 22

• has a greater range so cans serve devices across a wider area
• better at getting through solid objects/walls

Question 23

advantages of 5 GHz?

Answer 23

• much faster when communicating over short distances

- more non-overlapping channels so less chance of interference from other devices

Question 24

what is a client - server network?

Answer 24

• it is managed by the server and the devices connected to the server are clients
• files and software usually stored centrally on the server rather than on individual client devices
• clients send requests to the server, the server processes the request and responds
• this is the client - server relationship
• server stores user profiles, passwords and access information
• may request a password before fulfilling certain requests or deny access to people without the right access levels
• most uses on the network rely on client - server relationship

Question 25

pros/cons of client server networks?

Answer 25

pros:
-easy to keep track of files as stored centrally
-easy to perform backups
-easy to install and update software
-easy to manage network security
-servers are very reliable and always on
cons:
-expensive to setup and requires IT specialists to maintain
-sever dependence - if server goes down all clients lose access to their work
-server may become overloaded it too many clients accessing at once

Question 26

what are peer to peer networks?

Answer 26

• in P2P networks all the devices are equal, connecting directly to each other
• store files on individual servers and share them with others
• may use a P2P network at home to share files between devices

Question 27

pros and cons of P2P networks?

Answer 27

pros:

• easy to maintain, don’t need any expertise or expensive hardware
• no centralised management, devices need backups and security installed individually
• copying files between devices creates duplicate files, easy to lose track of whats stored where
• less reliable and data may be lost if one fails
• prone to slow down when other devices access them

Question 28

what is a network topology and the 2 main types?

Answer 28

the layout of a network, star and mesh

Question 29

what is star topology?

Answer 29

• in a star topology all the devices are connected to a central switch or server that controls the network
• the central switch allows many devices to access the server simultaneously
• star networks may be wired or wireless

Question 30

pros and cons of star topology?

Answer 30

pros:
-if a device fails or a cable is disconnected, rest of network is unaffected
-simple/easy to add more devices to the network
-better performance than other setups, data goes straight to the central device so all devices can transmit data at once and there are few data collisions
cons:
-in wired networks every device needs a cable to connect, can be expensive
-if there’s a problem with switch/server the whole networks affected

Question 31

what is mesh topology?

Answer 31

• it is decentralised, networking devices are either directly or indirectly connected to every other one without the need for one central switch or server
• they work by sending data along the fastest route from one device to another

Question 32

difference between partial and full mesh topology?

Answer 32

• in partially mesh not all devices are fully connected

- in full mesh every device is connected to every other device

Question 33

pros and cons of mesh topology?

Answer 33

pros:
-there is no single point where the network can fail, if one device fails then data is sent along a different route to get to its target
pros:
-they are very expensive, you need a lot of wire to connect so many devices together, however mesh uses wireless technology it is more of a practical option