Chapter 5: Networking Flashcards Preview

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Flashcards in Chapter 5: Networking Deck (71):


A collection of computers and peripheral devices connected together


What are a few types of networks?

1. LANs
2. WANs
3. MANs



Local Area Network: a collection of computers and peripherals connected together within a limited area


What kind of areas are LANs used in?

1. Residences
2. Schools
3. Laboratories
4. Office buildings



Wide Area Network: a collection of computers and LANs connected together over a large geographical area, often using leased infrastructure



Metropolitan Area Network: spans an entire city or campus, formed by connecting together multiple LANs


Order the following network types in ascending order of size:
1. MANs
2. WANs
3. LANs

3 1 2


What three main categories does the use of networks benefit?

1. Sharing resources
2. Communication
3. Centralised management


Advantages of using networks for Sharing Resources (3)

1. Shared resources can be accessed anywhere on the network from any computer
2. Ability to use shared peripheral devices, e.g. printers and scanners
3. Internet connection can be shared


Advantages of using networks for Communication (3)

1. Email can be used to communicate with colleagues
2. Messaging systems can be used to chat while working
3. Files can be transferred between computers easily


Advantages of using networks for Centralised Management (4)

1. User profiles and security can all be managed centrally
2. Software can be distributed across the network as opposed to individual installation
3. Users can use any PC on the network and access their own files
4. Data can be backed up centrally


Disadvantages of using networks (5)

1. Purchasing network cabling and file servers can be costly
2. Managing a large network is complicated and requires training. A network manager usually needs to be employed
3. If the file server goes down, files on the server become inaccessible. The computers can still be used, but are isolated
4. Viruses can spread to other computers throughout a computer network
5. Risk of being hacked, especially with WANs. Security measures, e.g. a firewall, are needed to prevent this


Network topology

A schematic description of the layout of a network


Bus Network

A topology where each device is connected to the main cable, referred to as the bus. Any device can transmit at any time, but only one transmission can occur along the main bus at any one time


Pros and Cons of Bus Networks (3 | 4)

1. Easy and inexpensive to install
2. Easy to add new computers to network
3. Broadcasting onto a bus is faster than transmitting around a ring network through many devices

1. Main cable failure leads to the whole network going down
2. Cable failures hard to isolate: affects all attached computers
3. Not secure - all data broadcasted on one cable
4. Performance slows down as the amount of traffic increases


Ring Network

A topology where each device is connected to the next in a loop. Uses a token-passing protocol to manage transmission one device at a time


Pros and Cons of Ring Networks (3 | 3)

1. Not dependent on a central computer
2. Token passing protocol is simple and reliable
3. Consistent performance even when there is a lot of traffic

1. A single node or link failure could potentially disrupt the whole network
2. Not secure - all connections shared
3. Slow - data goes around the whole network


Star Network

A topology where each device has its own cable connecting it to a central device, which can be a switch or server


Pros and Cons of Star Networks (4 | 2)

1. Failure of a cable only affects one station
2. Consistent performance even when the network is heavily used
3. Easy to add new computers
4. Most secure - messages transmitted down unshared links

1. Can be costly to install - lots of cabling needed
2. Dependence on a single switch: if this fails, the whole network goes down


What kind of networks are the following topologies used in:
1. Ring?
2. Bus?
3. Star?

1. LANs and MANs
2. LANs only
3. LANs and WANs


What two ways can the computers in networks be configured to behave in?

1. Client-server
2. Peer-to-peer



A method of organising devices in a network where all devices are of equal status instead of being designated specialised roles. Every computer can access resources on another computer, provided access rights have been granted


How are the computers in a peer-to-peer network connected together?

They are cabled together to form a LAN


Why might a small company use a peer-to-peer network?

It is not cost-effective to have a specialised server


1. Computer status
2(+/-). Setting up and maintenance
3(+/-). Management
4(+/-). Backing up
5(+/-). Dependency
6. Usage
7(+/-). Number of computers

1. All computers have equal status
2+. Easy to set up and maintain
3-. No centralised management - less secure
4-. Each computer backed up separately
5+. No dependency on a server
6. LANs only
7-. Impractical for over 10 computers



A method of organising devices in a network where some computers have roles as servers. These provide resources and services to other computers, known as clients. Management of the network and shared resources and files is centralised at the server


What are the two kinds of computers used in a client-server network?

1. Servers: holds data and controls access
2. Clients: where the user actually works


What is the job of a server computer? (3)

1. To control access to shared resources e.g. files, printers
2. Where all the data is stored, making data storage centralised
3. May have specialised roles e.g. print servers, dedicated to controlling access to shared printers and queuing print jobs


How do client and server computers interact with each other in school systems? (4)

1. User logs onto client computer using login details
2. Client computer connects to the server
3. Server verifies user login
4. Server gives user access to files they have permission for


How can a client-server network approach be used across a WAN? (2)

1. The browser acts as a client to the web server, which is somewhere in the world
2. Companies have centralised databases, which are accessed across a WAN by applications on client computers


Why is the client-server architecture used across a WAN?

It means that the data can be stored in one place, and can still be accessed by a large number of client devices worldwide


1. Computer status
2(+/-). Setting up and maintenance
3(+/-). Management
4(+/-). Backing up
5(+/-). Dependency
6. Usage
7(+/-). Number of computers

1. Specialised roles of either clients and servers
2-. Needs a network manager to run the network or web server
3+. Centralised security and management
4+. Backup done from central server
5-. Dependent on central server
6. Large LANs and WANs
7+. Can contain hundreds of computers


What is the basic principle of a client-server system? (3)

1. The client requests data
2. The server processes the request
3. The server returns a response accordingly


Fill in the blanks:
In client-server architectures, there are __ distinct parts to the coded solution, with a __________ between them. Part of this solution will execute at the __________, part at the __________.

1. 2
2. Network connection
3. Server end
4. Client end



A global computer network providing a variety of information and communication facilities through the use of standardized communication protocols


What kind of network is the Internet?



World Wide Web

An information-sharing model that is built on top of the Internet, making up a subset of the Internet


What are some examples of things that are part of the Internet, but not part of the World Wide Web? (4)

1. Email (relies on a mail transfer protocol)
2. Instant messaging OR Internet Relay Chat (IRC)
3. Internet gaming
4. File Transfer Protocol (FTP)



A set of rules that defines how information is transferred over the Internet



HyperText Transfer Protocol: the set of rules for transferring files on the World Wide Web


What happens when a browser requests a webpage using HTTP? (3)

1. Browser requests webpage
2. Server finds page
3. Webpage is sent back to the browser


Standalone applications:
1. Data storage
2. Network connection
3. Number of users
4. Availability needed
5. Code structure
6. Security measures

1. All data stored locally (disk or main memory)
2. No network connection to manage
3. Single
4. Used as needed, can be closed between uses
5. Modular structure less important
6. Local access rights on host PC is sufficient security


What happens when a browser sends a request for product information using a form on a webpage, which is connected to a database? (3)

1. Browser sends SQL data request
2. Server selects data from database from database and completes page
3. The webpage with the relevant data filled in is returned to the browser


Client-server applications:
1. Data storage
2. Network connection
3. Number of users
4. Availability needed
5. Code structure
6. Security measures

1. Data must be passed between the client and server
2. Must manage a network link
3. Multiple clients per server, so a request queue must be managed
4. Must be available all the time
5. Must be designed and created in a modular fashion
6. Clients have to be authenticated before data sent to them



The communication between a client and server device that initiates communication


Three-way handshake

The TCP/IP handshaking process that consists of three exchanges


What are the steps of the three-way handshake? (3)

What is the result?

1. The client sends a SYN to the server
2. The server sends back the client's SYN with an ACK
3. The client sends back an ACK

The client can now communicate with the server.


What is:
1. A SYN?
2. An ACK?

1. A synchronisation request
2. An acknowledgement



Transmission Control Protocol/Internet Protocol: the basic communication language of the Internet


Static webpage

The contents of the page are all coded into the page itself i.e. it does not have any content that updates automatically


Dynamic webpage

A webpage that is populated from a database, meaning that its contents are always current


Server end programming

Code that is executed at the server side of a client-server system


Client end programming

Code that is executed by the browser at the client side of a client-server system


What happens when an Internet sales company makes a website? (3)

1. A basic page layout is made
2. This is populated with relevant product details
3. Contents are usually based on search criteria


What are some examples of client-side programming? (4)

1. Storing data in cookies
2. Validating data form entries
3. Flash animations and Java applets that run on a page
4. Displaying pop-up ads when the mouse hovers over keywords



Where the computer software checks that data entered by the user is sensible and conforms to any defined rules


Examples of validation checks carried out on the client end (5)

1. Range
2. Type
3. Length: e.g. password length longer than 8 characters
4. Presence: makes sure needed information is entered
5. Format: e.g. postcode, email address


What does validation do?

It checks that entered data is reasonable, not whether or not it is correct


What does verification do?

It double-checks that data is entered correctly e.g. passwords, email addresses



Stored on the client computer, used by websites to store data which makes the pages more user-friendly


What is an example of what cookies do to make a page more user-friendly?

Prompting the user when they enter a username or search for something on the website



Small client-end programs that are embedded in webpages


What are some examples of server-side programming? (5)

1. Retrieving data from a database
2. Populating a page with the latest details
3. Checking usernames and passwords
4. Some forms of validation e.g. existence checks
5. Counting the number of site visitors



Hypertext Markup Language: defines the content and structure of a webpage using tags



Cascading Style Sheets: defines how components within a page will be styled using selectors


When creating a website, what is it considered good practice to do?

Use HTML for content and CSS for styling, as opposed to using inline styles


How was the content of webpages arranged in the past? (2)

1. The content and style were mixed together
2. In order to get a semblance of webpage design, content such as images were placed in invisible tables


Markup language

A language designed for the processing, definition and presentation of text


Scripting language

A language that allows you to record a set of repeatable instructions


What are a couple of examples of web scripting languages?

1. PHP
2. ASP


How can Python be used in web scripting?

Through the use of a special library such as Django