1.3.1 - Networks and topologies Flashcards
Types of network, factors that affect the performance of networks, client-server and peer-to-peer networks, network hardware, the Internet as a worldwide collection of computer networks, star and mesh network topologies
What is a Local Area Network (LAN)?
A network in a small geographical area (same building or a small site)
Who owns the infrastructure for a LAN?
Network owner
The organisation using it
What is a Wide Area Network (WAN)?
A network in a large geographical area (across a country or multiple e.g. The Internet)
Who owns the infrastructure for a WAN?
Third parties
What affects network performance?
- Bandwidth
-Interference (e.g. thick walls)
-Transmission media
-Amount of data being transmitted
-Error rate
-Latency
What is bandwidth?
The maximum amount of data that can be sent across a network at once. Measured in bits per seconds
What is latency?
The delay from transmitting media to receiving it. Caused by bottlenecks (a junction where data gets held up) in the infrastructure of the network.
Explain why the number of devices using a network at the same time can affect the performance of the network
-Less data can be transmitted at the same time.
-More devices means more data being transmitted at a time.
Explain why bandwidth can affect the performance of the network
-Bandwidth will be split between all devices
-therefore, there is less bandwidth for each device
Explain why latency can affect the performance of the network
Increased latency means that devices have to wait longer before they can transmit data
What are the advantages of using a Client-Server network?
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Controlled centrally: easy to backup data and update software
-Makes access to files more secure as sensitive data is stored on the server rather than on individual clients - Hardware, software and resources can be shared across the network
- Easy to add new clients to the network
What are the disadvantages of using a Client-Server network?
- Traffic congestion will cause network to slow down
- Reliant on server: If the server fails, the whole network fails and users will lose access
- IT technicians required to maintain the network
- Malware can spread from the server to all computers on the network
What are the advantages of using a Peer-to-Peer network?
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Simple setup: no server is required
-Cheaper: No specialist staff or expensive hardware required - Not dependent on a server
- Easy to share files between systems
What are the disadvantages of using a Peer-to-Peer network?
-
No central device to manage security or backups
-Less secure as security software is individually managed - More devices = decrease in performance
What kinds of network hardware are there?
- Wireless Access Point (WAP)
- Router
- Network Interface Card (NIC)
- Transmission medium
- Switch
What is a Wireless Access Point (WAP)?
Allows wireless enabled devices to connect to a network without cables
What does a router do?
Transfers data packets between networks.
Required to connect to a WAN. Uses IP addresses to route traffic.
What does a switch do?
Connects devices together on a network, allowing them to communicate.
-Sends data between computers on a LAN
-They segment the network by forwarding traffic to the correct location
-Switches learn which devices are connected and understand how to forward traffic in an intelligent way
What does a Network Interface Card (NIC) do? What does it contain?
They use a protocol to determine how the connection should work. They allow a device to connect to either a wired or wireless network.
They contain a unique hardware address, called a MAC address
Define the Internet
A worldwide network of computer networks
Describe how a computer tries to find the IP address for a given domain name
-A website is hosted on a web server
-The website has an IP address
-The user enters a URL (Uniform Resource Locator) into a web browser
-The web browser sends a request for the matching IP address to the URL to the DNS (Domain Name Server)
-If found, the IP address is returned
-If the DNS cannot find the IP it passes the request to a higher DNS
-If the IP address is not found return an error
-The IP address is sent back to the computer/browser
-The browser then sends a request to the IP address for the website
-The webserver processes the request for the website
-The web server sends the webpage to the user
Define hosting
Hosting is a service through which storage and computing services are provided to an individual or organisation for storage and maintenance of 1 or more websites.
Identify 3 tasks carried out by a router
-Converting packets from one protocol to another
-Transmitting packets
-Identifying the most effective path to the destination
What does the Cloud do?
Remotely hosts resources that can be accessed through the internet
Give at least 2 advantages of the Cloud
-You can access data in the cloud from anywhere as long as you have an internet connection
-It is environmentally friendly because it reduces the need for single-use storage devices such as CDs
-Makes it easier to share files with other users
-It is easy to add additional storage
-The cloud storage provider will provide a backup in case your files are lost so money doesn’t have to be spent on staff and hardware or software
-The Cloud provider is responsible for providing security so money doesn’t have to be spent on staff and hardware or software
-May be low cost and specialised skills aren’t required as specialised staff don’t need to be employed
-Cheaper as it doesn’t require already owned infrastructure
Give at least 2 disadvantages of the Cloud
-Cannot access files if there is no internet connection
-You are not in control of security procedures and reliant on third party (but firms could still be legally responsible)
-Reliant on third party for back up connection
-Data stored in the Cloud will be vulnerable to hacking and other threats, which the user has no control over
-There are issues regarding data ownership
-Implications of the 2018 Data Protection Act
Define a server
A device that provides services to clients.
Define a client
A device that requests access to a service provided by a server
What is a star topology?
Each computer system is connected to a central device (hub or switch)
What are the advantages of a star topology?
- Improved security as data packets are sent directly to and from the central device and not necessarily to all devices
- Easy to add new systems as they can be attached directly without the network needing to be shut down
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Fast transfer speeds as there are minimal network collisions
-If a single cable breaks only that computer is affected
What are the disadvantages of a star topology?
- Central device required to be purchased, installed and maintained
- If the central device fails, the whole network will fail
What is a mesh topology?
Each computer system is connected to every other computer system
What are the advantages of a mesh topology?
- Not reliant on central node: If one cable or system fails, data packets can take an alternative route
- Can withstand large amounts of data traffic due to the large possible number of routes and connections
- New systems can be added without disrupting the entire topology
What are disadvantages of a mesh topology?
- Large amount of cables mean it can be expensive to install and maintain
-Redundant cabling
