Networks

Question 1

Why use LAN

Answer 1

• easier to share files
• share the same hardware
• install software updates all at once
• user account can be stored centrally so users can login from any device on the network

Question 2

what is the function of a switch

Answer 2

connect devices on a lan, receive data(frames) from one device and transmit to another device on the network with the correct MAC adress

Question 3

what is the function of a router

Answer 3

transmits data between networks, can be used to connect a LAN to the internet

Question 4

what is the function of a WAP

Answer 4

connect devices in LAN, wirelessly using WiFi

Question 5

what is the function of a NIC network interface controller

Answer 5

allows the device to connect to the internet

Question 6

pros and cons of p2p

Answer 6

pro:
easy to maintain,
no dependence on server

con:
no centralised management, backup is more complicated
peer machines are less reliable as data may be lost if one fails,
machines are prone to slow down when other devices access them

Question 7

pro con of client server network

Answer 7

pro
easier to keep track of files
easier to back up
easier to manage security
servers very reliable and always on

con
expensive to set up and need IR specialist to maintain
server may become overloaded
server dependence

Question 8

TCP

Answer 8

sets of rules for how devices connect to the network,
split data into packets,
reassembles packet into original data,
chekcs data is send and discovered

Question 9

IP

Answer 9

responsible for direct data packets across a network

Question 10

FTP

Answer 10

used to access, edit and move files on other deivces

Question 11

smpt

Answer 11

used to send emails between servers

Question 12

pop3

Answer 12

retrieve email from a server, when user download the email, the server deletes it

Question 13

imap

Answer 13

retrieve email, the server holds the original email until the user deletes it

Question 14

What’s the difference between a LAN and a WAN

Answer 14

• LAN covers a small geographical area located in one single site
• and all the hardware is owned by one organization
• devices in LAN includes PCs, tablets, printers etc
• WAN connects different LANs in different geographical areas
• organizations hire infrastructures from companies that own and manage the WANs. WANs are much more expensive to set up

Question 15

Wired Ethernet Connections

Answer 15

• different types of Ethernet cables to connect a device to a LAN
• are fast and reliable

Question 16

what are CAT 5e or CAT 6

Answer 16

• common ethernet cables are CAT 5e and CAT 6. They are ‘twisted pair’ cables, containing four pairs of copper wires which are twisted together to reduce internal interference

Question 17

what are coaxial cables

Answer 17

singe copper wire surrounded by a plastic layer for insulation and a metallic mesh which provides shielding from outside interference

Question 18

what are fibre optics

Answer 18

data transmit as light
- high performance
don’t sufferer interference
- can transmit over a large distance without loss of signal quality

Question 19

what waves do wireless networks use

Answer 19

radio waves

Question 20

Bluetooth

Answer 20

direct connection between two devices so data can be shared
rage varies typically 10m
low bandwidth compared to wifi
often used in mobile/wearable devices

Question 21

Wi-Fi

Answer 21

used by multiple devices to connect to a LAN at the same time
connection rage between 40 - 100m
high bandwidth compared to Bluetooth

Question 22

wireless NIC

Answer 22

either built-in or you can use dongles
USB dongles
HDMI dongle

Question 23

factors that affect the performance of networks

Answer 23

• bandwidth: the amount of data that can be transferred in a given time
• number of devices connected/ heavy usage: available bandwidth is shared between the devices on a network. This can be sorted by limiting the bandwidth of each user
• signal quality (wireless), rage and physical obstruction
• wired are generally faster and more reliable than wireless
• choice of hardware and topology

Question 24

star topology pros and cons

Answer 24

devices all connected to a central switch/server

pros

• failure of one node, rest of the network is unaffected
• easy to add more devices
• better performances than other setups - all devices can transmit data at once with few data collisions

cons

• every device needs a cable to connect to the central server, making it expensive
• switch/server failure will lead to the whole network affected

Question 25

mesh topology

Answer 25

decentralized, all devices directly or indirectly connected. Data are sent along the fastest route.

• no single point of failure, if one fails data can go a different route
• expensive - a lot of wires are needed, but wireless technology makes it more practical.

Question 26

what is a network protocol

Answer 26

rules for how devices communicate and how data is transmitted across a network

network standard is a set of agreed requirement for hardware and software

standards are important as they allow manufacturers to create product

Question 27

MAC address communication on the same network

Answer 27

• every device needs a unique identifier
• MAC address are assigned to all network enabled devices by the manufacturer
• unique and cannot be changed
• 48/64 bit binary numbers and to make easier they are normally connected to hex
• ethernet protocol on LANs and switches read the mac address and use them to direct data to the correct decice

Question 28

IP address between different networks

Answer 28

IP are used when sending data between TCP/IP networks eg over the internet

IP are assigned manually or automatically before device can access the network

IPv4(32 bits) IPv6(128 bits)

ipv6 split into 16bits
ipv4 split into 8 bits

Question 29

network protocal layers

Answer 29

self contained
each layer serves the layer above it

data only transferred between adjacent layers (ie 1 with 3, 2 with 1 or 3)