SLR 11 Flashcards
Networks
What is a network?
Multiple devices which are all connected via a cable or through wireless
IN ORDER TO SHARE RESOUCES (IMPORTANT!)
What are the advantages of a network?
- Users can share files
- Users can share peripherals and connections to other networks such as the internet
- Users can access files from any computer on the network
- Servers can control security, software updates, and backups of data
- Allows communication
What are the disadvantages of a network?
- Increased security risks to data
- Malware and viruses spread easily between computers
- If a server fails the computers connected may not work
- Computers may run slower if there is a lot of data travelling on the network
What is a standard?
A set of hardware and software specifications that allow manufacturers to create products which are compatible with each other
Why are standards needed?
They are need for devices to interact
What are protocols?
They a set of rules or procedures for transmitting data between computers
What is TCP?
Transmission Control Protocol
Allows for communication over LAN/WANs
What is IP?
Internet Protocol
Allows for communication over LAN/WANs
What is UDP?
User Datagram Protocol
Allows for communication over LAN/WANs. It is similar to TCP but it doesn’t remove errors so its basically useless
What is TCP/IP?
TCP and IP combined which makes up the TCP/IP protocol stack, which provides the foundation of all internet communication
What is HTTP?
Hypertext Transfer Protocol
Allows for the client to send and recieve requests and is a fundamental protocol
What is HTTPS?
Hypertext Transfer Protocol Secure
Allows for the client to send and recieve requests and is a fundamental protocol, but SECURE!
What is FTP?
File Transfer Protocol
Allows for file transfers
What is POP?
Post Office Protocol
Takes emails from the server and places it on your device and removes it from the server
What is IMAP?
Internet Message Access Protocol
Keeps emails on the server after placing it on your device
What is an ISP?
An Internet Service Provider
What makes up the backbone of the internet?
The ISP is connected to a Domain Name Service (DNS) and other routers make it up
What is layering?
Dividing a simple task of networking into smaller and simpler tasks that work in tandem
What are the advantages of layering?
- Reduces a complex problem into a smaller sub-problem
- Devices can be manufactured to operate at a particular layer
- Products from different vendors will work together
What is the TCP/IP protocol stack made up of?
The Application Layer-
Network applications operate at this layer
The Transport Layer-
Sets up communication for language and packet-size
Internet Layer-
Addresses routes and packets across a network
Link Layer-
Faciliates transmission
What is MAC?
Media Access Control
Added the link layer to add the address for:
1. The source device
2. The destination device
What does the MAC and IP address do?
MAC Address-
Tells me who you are
IP Address-
Tells me where you live
How does requesting a url work?
When a user requests a url, the domain sends the DNS to find the IP address, then returns it to the browser via a GET request
What is a LAN?
A LAN is a Local Area Network
They cover a small geographical Area
What is a WAN?
Wide Area Network
Covers a large geographical area made up of multiple LANs
What is circuit switching?
A way data is sent
Circuit switching creates a fixed bandwidth between the source and destination throughout the transmission
What is packet switching?
A way data is sent
Breaks streams of data apart into smaller blocks named packets which guarentees bandwidth but not high quality. This makes it more affordable
How does Circuit Switching work?
- Physical path between source and destination
- All packets use the same path
- Reserves bandwidth in advance
- Can cause a lot of bandwidth wastage
- No store and forward transmission
How does packet switching work?
- No physical path
- Packets travel independently
- Does not reserve bandwidth
- No bandwidth wastage
- Supports sort and forward transmission
What can malware do?
- Delete, corrupt or encrypt files
- Cause computers to crash
- Reduce network speeds
- Logging keyboard inputs
What info can spyware track?
Internet surfing habits
Email addresses
Visited web pages
Downloads
Passwords
Credit card numbers
Keystrokes
Cookies
What is a DOS?
A denial of service attack
Floods servers with useless traffic to overflow it and crash it. This can cause the victim time and money.
What is an SQL injection?
Where code is injected into text boxes so that the server executes them
What is phishing?
An online fraud technique used by criminals to make people give out personal information
What does pharming do?
Sends users to fraudulent websites without their knowledge
What can prevent threats by malware?
Firewall - blocks unwanted traffic
Anti-malware
Proxy- bans websites
Encryption
What are the examples of network hardware?
Modems, Routers, Cables, Network Interface Cards (NIC), Wireless Access Points (WAP), Hubs and Switches
What does a modem do?
Transforms digital stuff from your computer into analogue symbols
From your ethernet/router to the outside world
What does a client server allow?
- Control access and security for stored files
- Manages access to the internet
- Manages printing jobs
- Provides email services
- Runs regular backups of data
What are the advantages of a client server?
- Easier to manage file security
- Easier to backup stored data
- Easier too install software updates to cell computers
What are the disadvantages of a client server?
- Can be expensive to set up and maintain
- Requires an IT specialist
- The server is the single point of failure
- Users will lose network access if the server fails
What does a peer-to-peer model work?
- A peer is a computer connected to a network
- A peer is equal to all other peers
- Peers serve their own files and are responsible for their own security and data backups
- Peers usually have their own printers
- Peers can send print jobs to other peers
What are the advantages of a peer-to-peer system?
- Very easy to maintain
- No specialist staff needed
- No dependency on one computer
- Cheap to set up
What are the disadvantages of a peer-to-peer system?
- Less secure
- Users need to manage their own backups
- Can be difficult to maintain a well-ordered file stored
