Chapter 2 #8

Question 1

Module 1: Network Fundamentals and Scales

Question 2

Define a Network “Node.”

Answer 2

Any device connected to a network, such as a computer, storage device, or peripheral (e.g., a printer).

Question 3

Define Personal Area Network (PAN) and Wireless Personal Area Network (WPAN).

Answer 3

PAN: Centered around a person or workspace to connect personal devices.
WPAN: A wireless local network connecting devices in very close proximity, such as a laptop, smartphone, and printer.

Question 4

Define Local Area Network (LAN) and Wireless Local Area Network (WLAN).

Answer 4

LAN: Covers a small area like a single building.
WLAN: A wireless version of a LAN that uses radio waves for communication instead of physical cables.

Question 5

Define Metropolitan Area Network (MAN) and Wide Area Network (WAN).

Answer 5

MAN: Covers several buildings in a city, larger than a LAN but smaller than a WAN.
WAN: Covers a very large geographical area, potentially connecting computers thousands of kilometres apart.

Question 6

What are the primary features of a WAN?

Answer 6

A WAN is composed of many LANs connected together through a Public Switched Telephone Network (PSTN) or satellites.
WANs can connect computers that are thousands of kilometers apart.
Often utilises fibre-optic cables and switch-to-switch transmission.

Question 7

What are some hardware and software components of a network?

Answer 7

Hardware: (Wireless) routers, Switches, Cables.
Software: Firewalls, Operation and manegment of the network (sending and reviving data packets).

Question 8

What are some benefits of networking?

Answer 8

1. Sharing peripheral devices.
2. Software licenses for networks are cheaper.
3. Users can share data easily.

Question 9

What are some drawbacks of networking?

Answer 9

1. High initial cost for setup.
2. Complex manegment.
3. Security threats from malware and hacking, as if one device is hacked, the entire network is compromised.

Question 10

Module 2: Network Models and Architecture

Question 11

Define the Client-Server model.

Answer 11

A network model where computers that serve, provide resources or services are servers and computers that request those resources/services are clients. Tasks are split between the two.

Question 12

Describe the role of clients and servers on the internet.

Answer 12

Web pages/files are saved on servers. Clients send requests to the web servers (for the files/pages).
Web servers process the requests and return the results to the client, and the client (computer) displays the results to the user.

Question 13

Describe the key features of a peer-to-peer network.

Answer 13

1. All computers are of equal status.
2. Each computer provides access to resources and data.
3. Computers can communicate and share resources.
4. Each computer is responsible for its own security.

Question 14

List the 6 key terms in the BitTorrent (P2P) process.

Answer 14

1. Peer: Any computer connected to the network.
2. Swarm: All peers sharing or downloading parts of the same file.
3. Seed: A peer with 100% of the file.
4. Leech: A peer with an incomplete file currently downloading from others.
5. Tracker: Central server storing details and IP addresses of the swarm allowing them to connect.
6. Torrent File: Created by original peer, cotains metadata (acts as a map to the clients with a specific file).

Question 15

Outline the process of setting up and using a peer-to-peer network.

Answer 15

1. Torrent file is made avalible for download.
2. File to be shared is split into pieces.
3. BitTorrent client software is made avalible for other peers, allowing them to work as seeds or leeches
4. A peer can act as a seed when uploading parts of a file.
5. When a peer is downloading a file it can get parts of the file from different seeds simultaneously.
6. That peer then becomes a seed for the downloaded parts.
7. Tracker keeps records of all the peers and the parts of the file they have.

Question 16

Describe the benefits of the usage of peer-to-peer networks.

Answer 16

1. Distributes the file data across multiple users, reducing the load on a single server.
2. Downloads from multiple sources simultaneously, speeding up the process of downloading a file.
3. If one source goes offline, others can still provide the file.

Question 17

Describe the drawbacks of the usage of peer-to-peer networks.

Answer 17

1. Reduced security, so the network is only as secure as the weakest computer on the network, and each computer is at risk from viruses from other computers
2. No central management of backup, if the data from one computer is not backed up it is lost to all of them
3. No central management of files/software so consistency may be difficult to maintain as each computer may have different software from the others
4. Individual computers may respond slower because they are being accessed by other computers
5. To share files all the computers involved need to be switched on so the files may not be always available

Question 18

Compare Thin and Thick Clients regarding processing and dependency.

Answer 18

Thin Client: Dependent on a server for processing; most features fail without a connection.
Thick Client: Functions like a standard computer; performs most processing locally and can operate offline.

Question 19

List the pros and cons of Thin Clients.

Answer 19

Pros: Cheaper to expand; automatic central updates; centralised security.
Cons: High reliance on server/network link; high initial server startup costs.

Question 20

List the pros and cons of Thick Clients.

Answer 20

Pros: Robust and works offline; more user control over data.
Cons: Less secure (individual responsibility); requires manual software updates per client.

Question 21

Module 3: Topologies and Collision Handling

Question 22

Define Bus and Star topologies.

Answer 22

Bus: Uses a single central cable (backbone); requires terminators to prevent signal reflection.
Star: All devices connect to a central hub or switch which directs data packets.

Question 23

What are the disadvantages of bus and star topologies?

Answer 23

Bus: Damage to the main cable would result in entire network failure, not secure (sends data to all computers)
Star: High initial installation costs, central hub faliure afects the entire network.

Question 24

How is data transmitted in packets in a star (switch) network?

Answer 24

1. Data packet has address of the recipent.
2. Sender transmits data packets directly to the central switch.
3. Server reads address and identifies where the recipient is in the network.
4. Central switch transmits data packets directly and only to recipient.

Question 25

Describe what is meant by a mesh topology.

Answer 25

1. All computers are connected to at least one other device 2. There are multiple routes between devices. 3. The computers can act as relays, passing data packets on towards the final destination (device).

Question 26

What are the advantages of using a mesh topology instead of a bus topology.

Answer 26

1. If one line (route) goes down there are more routes available. 2. Improved security as not using one main line. 3. New nodes can be added without interruption or interfering with other nodes. 4. Fewer collisions. 5. More secure as data is sent over a dedicated connection.

Question 27

Define Hybrid topologies.

Answer 27

A combination of two or more different topologies (e.g., star and bus).

Question 28

What is the CSMA/CD process.

Answer 28

It stands for Carrier Sense Multiple Access/Collision Detection. It is a collision handling protocol that detects collisions and resolves them in Ethernet connected cables

Question 29

Explain the CSMA/CD process steps.

Answer 29

1. Check: Device listens to see if the channel is idle. 2. Transmit: Sends data if clear. 3. Detect: If a collision is detected, transmission stops and a jamming signal is sent. 4. Wait: Both devices wait a random amount of time. 5. Retry: Transmit again.

Question 30

Module 4: Hardware and Connectivity

Question 31

Define NIC, WNIC, and (W)AP.

Answer 31

NIC: Network Interface Card. It is needed to allow a device to connect to a network. Contains a unique MAC address that identifies the device. WNIC: Wireless version of a NIC. (W)AP: (Wireless) Access Point; allows wireless enabled devices (devices with a WINIC) to conncet to a wired Network (LAN).

Question 32

What is the purpose of a switch/hub?

Answer 32

They allow two or more devices to connect and communicate together.

Question 33

Distinguish between a Hub and a Switch.

Answer 33

Hub: "Dumb" hardware that broadcasts data packets to all connected devices. Switch: Intelligent hardware that directs data packets only to specific destination addresses using MAC addresses.

Question 34

Define a Repeater and a Repeating Hub.

Answer 34

Repeater: A device that boosts/regenerates signals to prevent attenuation (signal loss). Repeating Hub: Combines hub functions with signal regeneration; also called an "active hub".

Question 35

Explain the role of routers and gateways in a network.

Answer 35

Router: Connects two (or more) networks, can connect a network to a WAN, receives packets from the internet and forwards them towards the destination using the IP address of the destination. Assigns private IP addresses to devices on the network. Operates between similar networks (networks using the same protocol) Gateway: Connects two (or more) networks, can connect a network to a WAN, receives packets from the internet and forwards them towards the destination using the IP address of the destination. Assigns private IP addresses to devices on the network. Assigns private IP addresses. Connects two dissimilar networks (networks that use different protocols) [Past Exam Q&A adds:] Additional router functions from exam Q&A: • To store / update / maintain a routing table • To find the most efficient path to the destination • To maintain a table of MAC and IP addresses

Question 36

Define Bridge, Modem, and Softmodem.

Answer 36

Bridge: Connects two LANs using the same protocol. Modem: Converts digital data to analogue (and vice versa) for telephone lines. Softmodem: A software-based modem using minimal hardware.

Question 37

What are the two modes a WNIC can opperate in and what are the requirements and stipulations of each mode?

Answer 37

Infrastructure mode: Requires a central Wireless Access Point (WAP) for communication. Ad hoc mode: Direct device-to-device communication without a central WAP.

Question 38

Module 5: Transmission Media and Bluetooth

Question 39

List features of Twisted Pair, Coaxial, and Fibre Optic cables.

Answer 39

Twisted Pair: Made out of copper wires. Cheapest but lowest data rate and most suceptabile to electromagetic interference. Coaxial: Copper core with mesh insulation. Better data transfer rates and less susceptible to electromagnetic interference. Fibre Optic: Glass fibres using light pulses. Highest data transfer rates, lowest attenuation, and are highly resitant to electromagnetic interference. Used to send data over long distances. Disadvantages: High cost and less flexible.

Question 40

Rank Radio, Microwave, and Infrared waves by Bandwidth, Penetration, and Attenuation.

Answer 40

Bandwidth: Infrared > Microwave > Radio. Penetration: Radio > Microwave > Infrared (blocked by solids). Attenuation: Infrared > Microwave > Radio (Radio travels furthest).

Question 41

Define Bluetooth & WIFI and Spread Spectrum Frequency Hopping.

Answer 41

Bluetooth & WIFI: They use electromagnetic radiation for communication. Frequency Hopping: Device randomly picks one of 79 available channels. If occupied, it picks another.

Question 42

Module 6: Addressing and Protocol Suites

Question 43

Define IP Address, IPv4, and IPv6.

Answer 43

IP: Unique address for every device on a network. IPv4: 4 8-bit parts in dotted decimal format that form a 32-bit address. (e.g., 192.168.1.1). IPv6: 8 16-bit parts in colon hexadecimal format that form a 128 bit address.

Question 44

What are the ranges of the values that can be used in IPv4 addressing?

Answer 44

Can consist of denary values. Range for values: 0-255

Question 45

What are the IPv6 Zero Compression rules?

Answer 45

1. Omit leading zeros within each 16-bit block. 2. Replace one contiguous string of zero blocks with a double colon :: 3. The :: can only be used once per address.

Question 46

Define Static vs. Dynamic IP and state the conflict that may arise when using IP adresses.

Answer 46

Static: Fixed address that does not change assigned by Internet Service Providers (ISPs) Dynamic: Temporary address assigned from a pool (via DHCP server) when connecting. Conflict: When two devices on a network are assigned the same IP address.

Question 47

Define Subnetting, NetID, HostID, and Subnet Mask.

Answer 47

Subnetting: Dividing a network into smaller sub-networks. NetID: Identifies the network. HostID: Identifies the specific host/device. Subnet Mask: Used to separate NetID from HostID.

Question 48

Identify three benefits of subnetting.

Answer 48

1. Improved preformance of network: Reduces broadcast traffic. 2. Enhanced Security: Limits network access between subnets using routers or firewalls for better security. 3. Scalability: Makes it easier to add networks without reconiguring everything

Question 49

Identify three differences between Public and Private IP addresses.

Answer 49

1. Private IP is only known within the LAN while Public IP is known outside of the LAN/on Internet 2. Public is allocated by ISP while Private is allocated by the router 3. Public addresses are unique throughout the Internet; private addresses are unique only within the LAN

Question 50

Explain why devices connected to a router have only a Private IP address, while the router has a public IP address and a Private IP address.

Answer 50

1. The router needs a public IP address so it can be identified on the Internet 2. The router needs a private IP address so it can be identified on the home network 3. The router has a public and a private IP address so that it can route data between the two networks (home and Internet) 4. The laptop needs a private IP address so it can be identified on the home network 5. The laptop does not have a public IP address because it does not connect directly to the Internet, this is more secure because it hides the laptop from the outside world, all data from the Internet must be transmitted via the router

Question 51

Module 7: PSTN, Cellular Networks and Satellites

Question 52

What is the PSTN and what is it based on?

Answer 52

Public Switched Telephone Networks consist of many different types of communication lines that allow data to be sent in both directions at the same time. The communication passes through multiple diferent switching centers before reaching their destination. Modern PTSNs use fiber-optic cabels for faster data transmission.

Question 53

What do ISPs take from PSTN, and do the ISPs own it?

Answer 53

ISPs take dedicated line services from the PSTNs to provide internet and communication to their customers. No, they do not own these lines, the lines are leased to them by the PSTNs.

Question 54

What are the two types of connection services offered by ISPs?

Answer 54

Internet Service Providers offer two types of connections: 1. A broadband network connection for traditional network access. 2. A WIFI hotspot technology, when internet connection is needed in a public place. This network is equiped with a WAP which has a connection to a wired network.

Question 55

What are the benefits of PSTNs?

Answer 55

1. Faster data transmission. 2. More consistent transmission speed. 3. Improved security.

Question 56

What are the drawbacks of PSTNs?

Answer 56

1. Expensive to set up. 2. If main line is damaged and connection is disrupted, there will be no alternatives.

Question 57

Compare PSTN vs. VoIP for phone calls.

Answer 57

PSTN (Public Switched Telephone Network): Traditional circuit-switched network; dedicated bi-directional path. VoIP: Packet switching; data is split into small packets; more efficient as it only transmits during active sound (when a call is being made).

Question 58

Outline the processes and hardware used in cellular networks.

Answer 58

1. Cell towers that are as possible apart, so that land is divided into cells that provide maximum line of sight (maximum connection coverage). 2. Each tower can recive and transmit data to and from phones through its antenna. 3. Data transmission is wireless using low power radio frequencies. 4. Multiple devices can communicate simultaneously to the tower.

Question 59

What are the main features of satellites?

Answer 59

1. Provide coverage over vast distances. 2. Essential for network communications where coverage is diffficult for cables. 3. They provide GPS

Question 60

Module 8: Resources and DNS

Question 61

Define the Internet vs. the World Wide Web (WWW).

Answer 61

Internet: Physical infrastructure; network of networks using TCP/IP. WWW: A service/collection of content (web pages) stored on websites. Uses HTTP/HTTPS protocols written in HTML and URLs which specify the location of a web page. Resources are accessed through web browers.

Question 62

A website can be accessed using either the Uniform Resource Locator (URL) or the IP address. Describe how a URL is converted into its matching IP address.

Answer 62

Uniform resource locator (URL) is sent to the nearest Domain Name Server. The URL is parsed to obtain the Domain name. DNS has a database that holds a list of Domain names and matching IP addresses. DNS name resolver searches its database for the Domain name. If DNS does not find the Domain name, the request is forwarded to a higher-level DNS. If the Domain name is found, the IP address is returned. If the Domain name is not found, the request is passed to a higher-level server. If the Domain name is finally not found, an error message is generated.

Question 63

Module 9: Data Transmission and Bit Streaming

Question 64

Define Ethernet and Ethernet Frames.

Answer 64

Ethernet: Protocol for wired LANs (IEEE 802.3). Ethernet Frames: Consist of Destination/Source MAC addresses, Payload (actual data), and FCS (Frame Check Sequence for error detection). [Like data packet structure]

Question 65

Define Bit Streaming and the role of Buffering.

Answer 65

Bit Streaming: Continuous sequence of bits sent over a network at high speed. Buffering: Temporary storage used to smooth out variations in speed (jitter) to provide continuous viewing.

Question 66

Compare Real-time and On-demand streaming.

Answer 66

Real-time: Live event; cannot be paused or rewound. On-demand: Pre-recorded files; full playback control (pause, rewind, fast-forward).

Question 67

What are the benefits of bit-streaming?

Answer 67

1. No need to wait for a whole file to be downloaded. 2. No need to store large files on the user's computer. 3. Allows on demand playback.

Question 68

What are the drawbacks of bit-streaming?

Answer 68

1. Video hangs/lags/stops if the broadband speed is low. 2. Video hangs/lags/stops if there isn't suffecient buffer space. 3. No internet means no access to files/films.

Question 69

Module 10: Storage and Computing

Question 70

Define Cloud Storage and Data Redundancy.

Answer 70

Cloud Storage: Data hosted on off-site servers. Data Redundancy: Storing the same data on multiple servers for increased reliability.

Question 71

List the 3 types of Cloud Computing.

Answer 71

Public Cloud: Data storage by a provider, accessible online. Private Cloud: Dedicated storage environment behind a company firewall. Hybrid Cloud: Mix of both.

Question 72

Give three benefits and three drawbacks of storing data using cloud computing.

Answer 72

Benefits: 1. Files and applications can be accessed from everywhere. 2. No need for separate (high capacity) storage devices (saves storage on existing devices). 3. Data can be easily shared online. 4. Cloud storage can be free (for small quantities). Drawbacks: 1. Can only access (the cloud) with internet access. 2. Security may not be strong (no control over security). 3. Needs a high broadband connection to upload and download large files. 4. It can take a long time to download/upload the data. [Past Exam Q&A adds:] Additional benefits: • Most cloud data services will have in-built backup/disaster recovery • Security could be better • Can easily increase capacity Additional drawbacks: • There may not be any backups // no control over backups • It can be more expensive in the long term • There could be a limit to the amount of storage unless paid for • There could be compatibility/access issues • There could be issues with the company offering cloud services

Question 73

Describe the functions of a Wireless Network Interface Card (WNIC).

Answer 73

1. Provides interface to wireless network (acts as an antenna). 2. Receives analogue radio waves and converts them to digital / binary. 3. Checks incoming transmissions for the correct MAC / IP address; ignores transmissions not intended for it. 4. Encrypts / encodes outgoing data. 5. Decrypts / decodes incoming data. 6. Takes digital/binary input and converts it to analogue radio waves, then sends them via the antenna.