ICT L.O.3 Flashcards
What is a Network?
Networks are connections between devices which enable resources and data to be shared.
(+) –> communication is faster and easier.
–> Resources are used more efficiently.
(-) –> Many networks are fixed in their arrangement and need cost/expertise to set up.
What are 2 types of networks based on behaviour?
1) Client-Server Networks–> Clients (devices/software) request data from servers (and servers provide data to clients).
-(Every device acts as either a client or a server)
(+)–>Provides centralized control
(-)–> can be expensive and difficult to run.
2) Peer-to-peer Networks–> Have no central servers, individual devices can switch between being clients and servers
(Each computer is equal in responsibility)
(+)–> Simpler to set up and maintain
(-)–> No managed security backups (Malware can spread quite quickly and illegal movies etc. are shared)
What is a server?
A server is a dedicated hardware or software that provides functionality for other programs or devices. (clients)
What are the different types of servers?
1) File Server
2) Printer Server
3) Application Server
4) Database Server
5) Web Server
6) Mail Server
7) Hypervisor
What is a File Server?
A file server stores data and allows clients to access their/shared files remotely.
What is a Print Server?
Manages print jobs and communicates with printers.
–>useful when there is a queue of people printing, or budgets (keeping track of what was printed and how much it cost)
What is a Database Server?
Hosts a Database (allows it to run) so is used to store large amounts of related data.
What is a Web server?
Hosts websites –> holds and supports websites (may connect to a database)
–>Allows clients to request and receive webpages through HTTP/S
What is a Mail server?
A server that sends, receives, stores, and manages emails.
-(May run the SMTP and/or POP protocols)
What is an Application Server?
A server which allows multiple users to access software.
(often used to access data from a database e.g., a central email system in a company
–>Acts as a layer of security as it will restrict certain applications to those with invalid access levels.
What is a Hypervisor?
A type of server that can create multiple virtual machines.
(The computer running the virtual machine is called the (Host) whilst the virtual machine is the (Guest)
–>The hypervisor allocates the underlying physical computing resources such as CPU and memory to individual virtual machines as required.
(Virtual machines are portable-meaning they can be moved between hypervisors)
What is Virtualisation?
Virtualisation is the act of presenting something to the user which is different to the physical reality.
-E.g.–> using one set of hardware to create multiple virtual machines
What is ‘Server Virtualisation’?
Allows one physical server to run multiple virtual servers/machines (each running separately)
What is ‘Client Virtualisation’?
A Virtual client has full desktop functionality, but processing and storage are done via a hypervisor.
What is Storage ‘Virtualisation’?
Data is stored across multiple physical devices but is presented as one/fewer devices.
What is ‘Cloud Virtualisation’?
When Data is held and processed in an off site location, either private or public
-Private–>company owns its own remote location
-Public–>remote location owned by a third party
(Hybrid virtualisation is usually a mix of public and private cloud services)
What are the Advantages and Disadvantages of Virtualisation?
(+)
–>Hardware can be used more efficiently as it can be shared to create multiple virtual machines
–>Reduced long-term cost (less hardware means reduced power consumption)
–> Easy to add new user
(-)
–>More complex (may need specialist staff)
–>If the hypervisor or host goes down, all users will be affected
–>Performance issues with high server load
What is a Client-Server Network?
Clients will make request to a server, the server manages the request and responds
(Client is completely dependent on the server to provide and manage the information)
What are the advantages and disadvantages of a Client-Server Network?
(+)
–>Network can be controlled centrally from the server to easily backup data and update software
–>Hardware, software and resources are shared e.g. printers/applications/data files
–>Improved scalability (clients can be easily added to the central server)
(-)
–>Large amounts of traffic congestion will cause network to slow down
–>If a fault occurs with the server, then the whole network will fail
–>IT technicians may be required to manage and maintain the network (costly)
–>Malware such as viruses can spread quickly across the network
What is a Peer-to-peer network?
Data is directly shared between systems without requiring a central server (each computer is equally responsible for providing data)
What are the advantages and disadvantages of a Peer-to-peer network?
(+)
–>Simpler to set up as no server is required
–>Clients not dependent on a server
–>efficient for quickly sharing flies between systems (e.g. such as downloading media files)
(-)
–>No central device to manage security or backups (backups must be performed on each individual system)
–>Computer performance will decrease with more devices connected to the network
What is a ‘Bus Topology’ and how does it work?
-The Nodes ( computers, servers, switches, routers, and even smartphones or IoT devices) are connected to a bus (a central cable which transfers all data on the network)
How it works:
1) Bus transfers data packets along the cable
2) Each computer checks the destination address contained in the packet to see if it matches its own
3) if it matches, it is accepted and processed
4) if it does not match, the computer system passes the data packet to the next system
What are the advantages and disadvantages of a Bus Topology?
(+)
–>Easy to attach another system to the main cable without disrupting the whole network
–>Quick to set up (once the main cable has been established) making it optimal for temporary networks
–>Cost effective as it contains less cabling than other topologies and requires no additional hardware (e.g. hub or switch)
(-)
–>Poor security (as data packs are passed on to each system on the network)
–>Data collisions are more likely (when 2 systems attempt to transfer data on the same line at the exact same time ) this will slow down the network
–>The main cable only has a limited length which can become crowded and slow down the network
What is a ‘Token Ring’ topology and how does it work?
-Computer systems are connected in a ring or a loop
How it works:
1) A token (small data packet) is sent around the ring in one direction, being passed from one computer system to the next.
2) A computer seizes the token and includes its own data when it transfers data
3) As the token arrives at each computer system, the system checks the destination address contained in the packet to see if it matches its own.
4) If the address matches, the computer processes the data otherwise it ignores it
What are the advantages and disadvantages of a Token Ring topology?
(+)
–> Data collisions are avoided as data packets are transmitted in one direction around the ring.
–>Attaching more systems to a ring topology won’t affect the transfer speed as much as other layouts like a bus topology because the data is transferred at a consistent speed.
(-)
–> if any system on the network fails then the network fails as the loop is broken and data cannot be transferred to all systems
–> to add a new system to a ring topology the network must be temporarily shut down
What is a ‘Star Topology’ and how does it work?
-Each computer system is connected to a central node (a hub or switch)
1) Each computer system is connected to the central node and transfers its data packets here
2) The hub/switch looks at the destination address and transfers the packets to the intended computer only
What are the advantages and disadvantages of a ‘Star Topology’?
(+)
–> Has improved security (as data packets are sent directly to and from the hub/switch in the centre and not necessarily all devices like in a bus or ring topology)
–> New systems can be attached directly to the central system so the network doesn’t need to shut down
–> Transfer speeds are generally fast as there are minimal network collisions
(-)
–> Extra hardware (hub or switch) is required to be purchased , installed and maintained
–> If the central system (hub or switch) fails then the whole network will be unusable until the error is fixed
What is a ‘Mesh Topology’ and how does it work?
-Each computer system is connected to every other computer system
1) Data packets are sent to the destination address along the quickest path, travelling from node to node.
(If a pathway is broken, there are many alternative paths that the packets can take)
What are the advantages and disadvantages of a ‘Mesh Topology’?
(+)
–>if one cable or system fails then data packets can take alternative routes and still reach destination address
–>can usually withstand large amounts of data traffic (because of large number of possible systems and connections)
–>New systems can be added to the network without disrupting the entire topology
(-)
–>Large amount of cables (can be expensive to install and maintain)
–>Redundant cabling should be avoided (when cables are connected between systems that won’t ever need to communicate)
What 3 pieces of information need to be configured before a computer system can use a network?
1) IP address–> used to uniquely identify computer systems on a network, allowing communication between them.
2) Default Gateway–> When data to be sent from one network to another, it must be sent through a default gateway.
e.g. the default gateway is usually a router that connects the local network to another network.
3) Subnet Mask–> Subnetting is the act of dividing a physical network into smaller ‘sub’ networks (known as subnets), this helps reduce traffic and means that users can externally access parts of a network
What is a ‘LAN’?
A Local Area Network is a network in which the computer systems are all located relatively close to each other, e.g. in the same building, or site, like a school.
examples include:
-Wifi
-Ethernet
-Token ring
What is a ‘MAN’?
A ‘Metropolitan Area Network’ covers a range of towns or cities, for example, a university network.
(They are usually very efficient at providing fast communication for cities, with high connection speed through the use of fibre optic cables)
examples include:
-Universities (with multiple campuses)
What is a ‘WAN’?
a ‘Wide Area Network’ spans a large geographical area, such as multiple cities or countries. (e.g. the internet)
examples include:
-ADSL
-ISDN
-Leased Line
-Fibre
What are all the different connectivity methods used in networks?
1) ADSL (Asymmetric Digital Subscriber Line)–>
Internet (data) is provided over telephone lines:
–>Has a faster download speed than the upload speed
–>Normally uses copper wires
–>Both data and voice can be transferred simultaneously (only due to a microfilter which is needed)
–>Firewall or VPN is required to improve security
–>Connection speeds are slowed down with more systems that use the network at the same time.
2) ISDN (Integrated Services Digital Network):
–>Older alternative to ADSL (now being phased out)
–> Internet (data) is provided over telephone lines
(like ADSL)
3) Leased Line–> A rented connection only used by you
–>Consistent performance
–>More secure than the others (as it is not shared)
What are all the different connectivity methods using Voice Networks?
1) PSTN (Public Switched Telephone Network):
-The wired network used for telephones + used by landlines for voice calls
(+)–> Audio quality is reliable and consistent
(-)–> Fixed with a limited range
2) Cellular–> The wireless network used for mobile (cell) phones:
–>used for data (internet) and voice
–>Radio towers broadcast to the surrounding area (their cell)
(+)–> Flexible
(-)–> There can be signal blackspots
3) Satellite–>Radio waves transmitted to and from space
–>Satellite phones can be used for audio calls
(+)–> Can be used anywhere
(-)–> There will be lag due to the long distance travelled
What are all the different types of ‘Business Systems’?
1) MIS (Management Information System)–>a system to collect, analyse, and store data. (often will link to a database
(+)–>integrates multiple tools
–>Improved customer service: MIS can help management improve customer service by providing more data about customer requirements
–>Better decision making as it can help organizations make better decisions by providing data in an appropriate form and allowing for speedy decisions
(-)–> can be complex, e.g. training staff will be required).
–>expensive to install and implement
–>Security issues: MIS can be vulnerable to security issues, such as hackers accessing private data
2) CRM (Customer Related Management)–> collect customer data and analyse it, they are designed to:
–>Maintain current customers
–>Entice prospective customers
examples include: Tesco club card (Loyalty cards/ surveys etc.)
(+)–>Used to understand customers’ wants and needs but (-)–> are only useful if the data quality is high.
3) SOP (Sales Ordering Process)–> The steps taken when a customer makes a purchase:
(1)–>Customer places order
(2)–>Process the order e.g. has the payment been received?/is there stock?
(3)–>Create a sales order (Details on what has been purchased)
(4)–>Fulfill order e.g. send sales order to a department
(5)–>May need to invoice the customer afterwards (if it is a big purchase)
4) SOP (Standard Operating Procedures)–> A policy giving a set of rules to follow
(+)–>This ensures consistency across employees and reduces the chances of errors but (-)–> It may not be comprehensive and can be inflexible.
5) Helpdesk–> Used to provide real-time support to a user or a trained member of staff.
(+)
–>Ticketing allows tracking of requests for support (different priorities can be dealt with in a certain amount of time)
–>Analysis can be conducted
(-)
–>Can feel overly rigid and monitored, and become a burden.
What are the advantages and disadvantages of a ‘LAN’?
(+)
-improved security centralised data is easier to protect backup
-Reduced costs enable shared peripheral
devices such as printers/ scanners
(-)
-Limited area: LANs only cover a small area, like an office or home
-Performance: Network performance can suffer as the number of users increase
What are the advantages and disadvantages of a ‘MAN’?
(+)
-High-speed networks: MANs use fiber optic technology, which offers faster data transfer rates and reduced latency than traditional copper cables.
(-)
-Higher costs: MANs are more expensive to implement and manage than local area networks (LANs). This is because they require more cable and skilled technicians and network administrators.
-More difficult to secure: MANs comprise of multiple LANs, which can make it harder to keep out hackers.
-More difficult to manage: MANs are large networks comprising of many LANs, making them challenging to manage.
What are the advantages and disadvantages of a ‘WAN’?
(+)
-Secure communication: WANs can provide a secure way to communicate between offices, even if they are far apart.
-Dedicated bandwidth: WANs provide dedicated bandwidth for an organization, which can be more secure than sharing bandwidth with other businesses.
(-)
-Cost: WANs can be expensive to set up and maintain.
-Security: WANs require additional security measures, such as encrypting data and paying attention to remote worker security.
-Performance: WANs can experience slower connection speeds, especially for large networks.
-Maintenance: WANs can have maintenance issues.
