Computer Networks

Question 1

WAN

Answer 1

Wide Area Network

Question 2

Internet is what type of network

Answer 2

WAN

Largest interconnected networks

Question 3

IP address

Answer 3

Internet Protocol address is the unique number - changes slightly as device moves location as location is needed to recieve signals

Question 4

Packet switching

Answer 4

File is broken up into data packets and each packet has a header saying IP address to go and from and the number of packets in the whole communication and error checking data

Question 5

Network Hardware

Answer 5

Routers
Switches
Network Interface Cards (NICs)

Question 6

Routers and Switches

Answer 6

A router is in a WAN and send packets along routers to intended recipient
Switch in LAN sends packets locally using MAC address

Question 7

NIC

Answer 7

Required to connect any network enabled device

Physical component that can operate wirelessly or use a standard Ethernet cable.

Question 8

Each NIC has a media access control (MAC). Computer may have more than one - separate ones for wired and wireless.and maybe Bluetooth. How many digits in what data types?

Answer 8

12 digits in hex

Question 9

WiFi stands for and advantages

Answer 9

Wireless fidelity
Mobility
Sharing files doesn’t need without having to be connected to a port
Expense time and inconvenience of laying cables through walls.
Instant data transfer is quicker - uploading to Facebook

Question 10

Disadvantages of wireless nextworka

Answer 10

File transfer speed are slow
Obstructed by walls furniture and ceilings
Less secure
Easier to hack

Question 11

Risks of wireless networks

Answer 11

Criminal activity - hacking
Bandwidth stealing - intruders use connection for their purposes slowing network down
Confidentiality - if encryption doesn’t occur before transmission an intruder can easily access

Question 12

LAN BENEFITS

Answer 12

Sharing resources - store files on file server so they can be accessed by authorised users from any computer on network, peripheral devices like printers and scanners can be shared,intenet connection can be shared
Centralised management - user profiles and security, software distributed across network rather than manual installation,files can be backed up centrally.

Question 13

LAN disadvantages

Answer 13

File server goes down, no one can access any files or do any work
Network falls could lead to data loss
Access may be slow because network traffic increases
Difficulty securing system from trackers
Viruses would affect every computer

Question 14

Topologies

Answer 14

Different layout of interconnected computers

Question 15

Star description and advantages

Answer 15

All the computers are connected to a switch by their own cable
One cable fails but won’t disrupt other devices
Consistent performance even during heavy use
Good security as data is only received by node it is sent to

Question 16

Star disadvantages

Answer 16

Expensive because of switch and cables

If switch fails entire network goes down

Question 17

Bus topology description and advs

Answer 17

All devices are attached to backbone main cable
Easy to install
Cheap
No reliance on central node

Question 18

Bus disadvantages

Answer 18

If the main cable fails the whole network goes down
Cable failures are hard to isolate because all computers are affected
Traffic increases so performance is slow
Low security as every node can see all the transmissions

Question 19

PAN

Answer 19

Personal are neat work like Bluetooth

Question 20

Ethernet

Answer 20

Protocols used in LANs - describes data transmission
Nodes will wait until connection is quiet before contacting each other
Two nodes attempting to transmit simultaneously will stop and each wait a random period before attempting

Question 21

Ethernet cables types advantages and disadvantages

Answer 21

Two types Ethernet - fibre optic and twisted pair copper
Copper - cheaper, rural areas use for telephones, speed is alright for most apps
Fibre optic - greater bandwidth, faster transmission, more durable, do not break as easily, only loses 3% of signal over 100m compared to 94% loss in copper

Question 22

Network security methods

Answer 22

Authentication
Encryption
Firewall
MAC address filtering

Question 23

Authentication

Answer 23

Username % strong password which contains numbers alphabets and symbols and is not shared with anyone - account locks after certain amount of failed attempts.
User Access Levels - some files are read only some can’t be accessed by lower clearances

Question 24

Encryption plus terminology

Answer 24

Protects data from being hacked or used illegally
Changes then original msg (plaintext) using code into ciphertext
An encryption algorithm is used and the other computer must have the key to access the data

Question 25

Caesar shift cipher

Answer 25

Shifts alphabet n times

Question 26

Firewall

Answer 26

Prevent unwanted internet traffic from gaining access to LAN Unauthorised users are blocked by firewall whcih csn also block access to ports such as FTP. It blocks data from certain IP addresses or ports

Question 27

MAC address filtering

Answer 27

MAC addressses that are permitted can join networks - doesn’t screen individuals though

Question 28

WAP

Answer 28

Wireless Accesss Point enables WiFi compatible devices to access internet via a wireless LAN

Question 29

TCP/IP stands for and does

Answer 29

Transmission Control Protocol/Internet Protocol TCP - defines the breaking down of data into packets and reassembly at destination. Detects errors and resends lost packages. IP - identifies location of device on the Internet and routes individual packets from the source to the destination

Question 30

UDP stands for

Answer 30

User Datagram Protocol Apps can send msgs (datagrams) to other hosts on an IP network Alternative to TCP/IP but no error checking or correction Maintains an open communication between recipient and sender during duration of communication hence is used in online gaming sessions.

Question 31

HTTP stands for and does

Answer 31

Hyper Text Transfer Protocol Used for accessing and receiving web pages in the form of HTML. Requests web server to transfer requested web page to the users browsers for viewing

Question 32

HTTPS stands for and does

Answer 32

Hyper Text Transfer Protocol Secure | Does sameas HTTP but encrypts data so is secure

Question 33

FTP stands for and demos

Answer 33

File transfer Protocol Trasnferijgn computer files from client to server Uses separate control and data connections between the client and the server

Question 34

IMAP stands for and does

Answer 34

Internet Messagign Access Protocols Email protocol that stored email msgs on a server but allows users to view and manipulate the msgs as though they are stored on own computers.

Question 35

SMTP stands for and does

Answer 35

Simple Mail Transfer Protocol sending emails between servers Sends out email from client and for relating or forwarding mail msgs - necessary if sender and recipient have different email service providers

Question 36

TCP/IP LAYERS ORDER and function

Answer 36

Application - network apps like browser operates. Data is encoded so means formatting data and adding the correct header eg HTTP,HTTPS,FTP,IMAP,SMTP Transport - sets up communication between two hosts and establishes settings like language and packet size. Data is split into packets and adds packet info like what packet number it is and total. Hides different architectures of network. TCP/UDP Network/Internet Layer - addresses and packages data for transmission and routes the packets across the network. Attaches senders IP address IP Link - NIC is located and OS device drivers. MAC address of sender and recipient is attached allowing the direction of the packet to a specific device on LAN for example