1
Q
What is a computer network.
A
a collection of computers that are connected together
2
Q
Advantages of computer networks: (5) if u get 4 then good enough
A
- users can share files and resources
- users can access their files and resources from another computer on the same network
- servers can be created to centrally control a number of operations and services on a network (e.g: security and file backup)
- communications can be sent to any computer on the network
- peripherals can be shared
3
Q
what is a peripheral
A
a device that is attached to a computer system
4
Q
disadvantages of networks: (5)
A
- networks can be subject to security issues, allowing unauthorised access to users’ files and resources SINCE malware and viruses can easily be spread between computers and it may be difficult to take control of the issue
- (depending on the structure) if an element of the network fails, it could cause problems for the rest of the network
- high amounts of network traffic can cause a network to run slowly
- expensive to maintain
- may need to employ a server manager
5
Q
what does LAN stand for, how far does it cover, and where is it used? (3)
A
- Local area network
- small geographic area
- home, schools, office buildings
6
Q
what does PAN stand for, how far does it cover, and why is it used? (3)
A
- personal area network
- only a few metres
- to transfer data or share internet between devices close together
7
Q
what does WAN stand for, how far does it cover, what is it made of, and where is it used? (3)
A
- wide area network
- large geographic area (anything from a city to several countries)
- huge, global organisations
- is often a collection of connected LANs
8
Q
ownership of the three forms of network? (3)
A
LAN: owned by an individual or organisation
WAN: often under collective or distributed ownership.
PAN: owner is user of the network
9
Q
are networks wired or wireless?
a) wired
b) wireless
c) both
A
c) both
10
Q
what are the three types of cables that can be used for wired networks?
A
- coaxial
- twisted pair
- fibre-optic
11
Q
how does a coaxial cable look like, and what is it used in mainly?
A
- has a central wire which is surrounded by an insulating layer
- has a final outside layer that acts as a jacket
- used in Ethernet
12
Q
how does a twisted pair cable look like, and what is it used in mainly?
A
- two separately insulated wires which are twisted around each other
- surrounded by a sort of ‘jacket’
- most common for a network
13
Q
how does a fibre-optic cable look like, what is special about it, and what is it used in mainly?
A
- lots of very fine glass threads inside an outer layer
- special bcos uses glass instead of cable
- is used in networks
14
Q
advantages of wired (vs wireless) (8) - having 5 is enough
A
- Stability: They are less susceptible to interference and signal loss, providing a consistent and predictable network performance.
- Security:
Less vulnerable to hacking: Physical access is required to connect to a wired network, making it harder for unauthorized users to gain access. - Speed: Higher data transfer rates
- Reduced interference: Wired networks are not susceptible to the same types of interference that can affect wireless networks, such as electronic devices, walls, or other obstacles. This results in more consistent and reliable performance.
- Less congestion: In areas with a high density of wireless networks, there can be congestion and interference issues. Wired networks, on the other hand, can handle a higher number of connected devices without experiencing the same level of congestion.
- Lower power consumption: Wired devices typically consume less power than their wireless counterparts.
Longer Range: - Immunity to Radio Frequency Interference (RFI) and Electromagnetic Interference (EMI):
Resistance to external interference: Wired connections are less susceptible to RFI and EMI, which can affect the performance of wireless networks. This makes wired networks more reliable in environments with high levels of electromagnetic activity. - Easier Troubleshooting: The physical nature of the connections makes it easier to identify and resolve problems compared to the sometimes complex and variable nature of wireless issues.
.
15
Q
advantages of wireless (vs wired) (5)
A
- Mobility: Wireless networks allow users to connect to the internet or a local network without the constraints of physical cables. This is particularly useful for devices like laptops, smartphones, and tablets that need to move around.
- Ease of Installation: There’s no need for physical cables, which can simplify the installation process.
- Reduced Infrastructure Costs: There is no need for extensive cabling, which can result in lower installation and maintenance costs.
- No Physical Barriers: Wireless networks eliminate the need for physical cables, reducing clutter and making it easier to set up and reconfigure the network. This can be especially advantageous in environments where wiring is impractical or aesthetically undesirable.
- Quick Implementation: Wireless networks can be quickly deployed which makes them ideal for temporary networks
16
Q
what is a network topology?
A
the physical structure of a network
17
Q
what is the topology of a star network?
A
there is a central computer/server that all other computers are directly connected to
18
Q
what is a bus topology?
A
- there is one central backbone of cable that every computer in the network is connected to
- at the end of the central cable is a terminator, which stops data from continuously being moved around the network
19
Q
pros of star network? (3)
A
- if a computer fails, it has little effect on other computers (unless if it is the server)
- no data collisions
- transmission of data is fast
20
Q
cons of star network? (1)
A
- expensive as it needs a central controlling cable and a large amount of cabling to connect each computer
21
Q
pros of bus network? (3)
A
- The length of cable required is less than a star topology (compact)
- It is easy to connect or remove devices in this network without affecting any other device.
- Very cost-effective as compared to other network topology i.e. mesh and star
22
Q
cons of bus network? (5)
A
- Troubleshooting individual device issues is very hard.
- terminators are required at both ends of the main cable.
- If the main cable is damaged, the whole network fails or splits into two.
- Packet loss is high.
- This network topology is very slow as compared to other topologies.
23
Q
what is a network protocol? (2)
A
Network protocols are a set of rules outlining how two or more connected devices communicate across a network to exchange information easily and safely
24
Q
What is ethernet?
A
Ethernet is a family of related protocols that is used to connect multiple computers in a local area network
25
What is Wifi and its purpose?
- Wi-Fi is a wireless family of related protocols used to connect computers, tablets, smartphones and other devices to the internet.
- Wi-Fi is a trademark and the generic term for networks of this nature is WLAN.
26
What is TCP and its purpose?
- transmission control protocol
- a communications standard that enables application programs and computing devices to exchange messages over a network
27
What is UDP and its purpose?
- user datagram protocol
- a **communications protocol** for time-sensitive applications like gaming, playing videos, or Domain Name System (DNS) lookups
28
What is IP and its purpose?
- internet protocol
- identifies every device connected to the internet
- allows communication over internet and on LANs
29
What is HTTP and its purpose?
- Hypertext Transfer Protocol (HTTP)
- a method for encoding and transporting information between a client (such as a web browser) and a website
30
What is HTTPS and its purpose?
- hypertext transfer protocol secure
- a protocol that secures communication and data transfer between a user's web browser and a website
- HTTPS is the secure version of HTTP.
31
What is FTP and its purpose?
- file transfer protocol
- used for the transfer of files from one host to another over a TCP-based network, such as the Internet
32
What is SMTP and its purpose?
- simple mail transfer protocol
- is used to send and receive mail
33
What is IMAP and its purpose?
- internet message access protocol
- allows you to access your email wherever you are, from any device
34
what is the need for/importance of network security? (1-2)
- both wired + wireless networks are susceptible to cyber-attacks (damaging the network or gaining unauthorised access)
- the results could be fatal (e.g: loss of data, loss of functionality)
(great care should be taken to prevent these attacks from occurring)
35
what is authentication? (and 2-factor authentication)
- when users are encouraged to set strong passwords to their accounts
- 2FA involves asking the user for their password, then showing them a code requiring them to use another device to see and blah blah blah
36
what makes a strong password? (4)
- usually 8 or more characters
- combination of letters, numbers and symbols
- combination of lowercase and capital letters
- is not identifiable data linked to the user (e.g: birthday)
37
what is encryption (and what is the purpose)? (2)
- Scrambling data to make it unreadable, to add security to transmitting the data.
38
what is a firewall?
A security measure that prevents unauthorised traffic coming into and leaving a network, by using a set of rules.
39
what is MAC address filtering?
- each network interface card in a computer is given a u i que hardware value called a media access control (mac)
- only devices that have a NIC with specific MAC address can join the network
40
what layer of the TCP/IP model does this protocol operate in: HTTP
application layer
41
what layer of the TCP/IP model does this protocol operate in: SMTP
application layer
42
what layer of the TCP/IP model does this protocol operate in: IMAP
application layer
43
what layer of the TCP/IP model does this protocol operate in: FTP
application layer
44
what layer of the TCP/IP model does this protocol operate in: TCP
transport layer
45
what layer of the TCP/IP model does this protocol operate in: IP
internet layer
46
what are the four layers of the TCP/IP model?
- application layer
- transport layer
- internet layer
- link layer
47
what is the application layer?
this is where the network applications, such as web browsers or email programs, operate.
(contains everything that sends info)
48
what is the transport layer?
this layer packetises the information given to it by the application layer
49
what is the internet layer?
The Internet layer, also known as the network layer or IP layer, accepts packets and ensures that they are going to go to where they need to go? (kinda like stamping an email)
50
what is the link layer?
the central hub in which all information passes through. (like the mailman delivering a letter)
51
which cable carries data the fastest?
fibre-optic
52
Explain how SMTP works, and what does it stand for + which layer of TCP/IP is it on? (4)
(i made the exam question myself so…)
simple mail transfer protocol + application layer
(probably) ANY THREE FROM:
- enables users to send (and receive) email messages
- initiates sessions between user and mail server
- server then forwards messages
- server uses a process called ‘store and forward’ to store messages and forward as necessary
- server decides which server to send the message to and the inbox provider then downloads the message and places it in the recipient’s inbox
- often used in conjunction with IMAP
53
Explain how IMAP works, and what does it stand for + which layer of TCP/IP is it on? (4)
(i made the exam question myself so…)
instant message access protocol + application layer
ANY THREE FROM:
- stores email messages on an internet service provider’s (ISP) server but allows users to manipulate messages as though in a local device
- local devices access ISP server to access messages
- works with desktop clients and webmail clients
- allows simultaneous logins from diff devices to one account
54
Explain how FTP works, and what does it stand for + which layer of TCP/IP is it on? (3)
(i made the exam question myself so…)
- file transfer protocol + application layer
- allows secure transfer of files between client and server
- files are uploaded to and downloaded from the server using FTP
55
Explain how TCP works, and what does it stand for + which layer of TCP/IP is it on? (4)
(i made the exam question myself so…)
- transmission control protocol (transport layer)
ANY THREE FROM!
- connects network devices to the internet
- defines how applications can create channels of communication across a network
- it manages how a message is assembled into smaller packets before transmission and reassembles packets in the correct order at destination.
56
Explain how UDP works, and what does it stand for + which layer of TCP/IP is it on? (4)
(i made the exam question myself so…)
user datagram protocol + transport layer
ANY THREE FROM:
- communications protocol
- establishes low latency and loss-tolerating communication between applications
- enables transfer of data before an agreement is provided by recieving party
- this speeds up transfers
- unreliable communication
57
Explain how IP works, and what does it stand for + which layer of TCP/IP is it on? (4)
(i made the exam question myself so…)
internet protocol - internet layer
- relays data across network boundaries
- defines how to address and route each packet
- to make sure it reaches the correct destination
