Section 4: Computer Networks Flashcards
Describe a router and its purpose
A router is a network device that connects together two or more networks.
It’s usually used to join a home or business network (LAN) to the Internet (WAN).
The router will typically have the Internet cable plugged into it, as well as a cable, or cables to computers on the LAN.
The LAN connection might be wireless (WiFi), making the device a wireless router.
Describe the use of WIFI in networks
+Uses radio signals (WiFi) to connect computers instead of cables.
+At the centre of the WLAN is a wireless switch or router used for sending and receiving data to the computers.
+WLANs are more difficult to make secure since other people can also try to connect to the wireless network.
–> Use passwords
Describe the use of Bluetooth in networks
+Bluetooth is a wireless networking technology designed for very short-range connections
+ Get rid of all cables and peripherals
+Bluetooth devices contain small, low-power radio transmitters and receivers. When devices are in range of other Bluetooth devices, they detect each other and can be ‘paired’
Define LAN
Local Area Network (LAN) is a network confined to one building or site.
Describe how to set up a small network
Buying hardware:
+ Switches / hubs - to link devices together
+Network cables to connect devices to the switch, etc.
+A separate wireless access point to allow wireless devices to join the network
+A router to connect your LAN to the Internet (WAN)
+A firewall to protect your network from hackers
+Server(s) to manage network functions such as network security, network file storage, shared resources (such as printers)
Organise:
+Set up an account with an Internet Service Provider (ISP)
+Get an Internet connection installed from the ISP to your location
What is user ID and Password? What is their purpose?
-It’s the most common way of data protection.
This method identifies you as an authorised user.
User ID is the name of your account, password is the secret code that only the user knows.
–> Reduce the risks of outsiders getting into the system.
-A password is a set of secret numbers and/or letters which match with a username to grant access.
Define WAN and give characteristics
Wide Area Network (WAN) is a network that extends over a large area.
A WAN is often created by joining several LANs together
eg: The Internet
Define Wireless Local Area Network and give characteristics
A wireless LAN (WLAN) is a LAN that uses radio signals (WiFi) to connect computers instead of cables.
Describe characteristics and common use of Intranet
Private Network that provide similar services to the Internet.
Used for:
+ Viewing internal web pages.
+ Emailing and instant messages between people within a group.
+ Sharing internal documents.
What is the Internet? Why do we use it?
The Internet is made up of millions networks brought together, forming a vast "inter-network". Used to: \+ View webpages on WWW \+ Shari files. \+ Emails \+ Listen to streamed music/video \+ Play interactive games
What is a hub?
Hub is a hardware devices that connects multiple computers together to share data packages to make a LAN.
When it receives a message, it send data to any other computers in the network –> not secure.
Used in the center of a Star network
What is a switch?
A device that connects computers together to make a LAN.
More intelligent than the hub because when it receives a message, it addresses the recipient and send it to the specific computer –> more secure but more $
What is a bridge?
A network device that links two different parts of a LAN. ( links 2 networks not 2 computers)
Different from router since router links LAN to a WAN, Bridge only connects 2 LANs to make it act as a single LAN.
What is a proxy servers?
A computer setup to share resource, usually an Internet connection.
Computer visit web pages –> proxy server –> ISP –> web pages.
Usually used instead of router because we can add additional software like antivirus, web filtering…
What is encryption?
Encryption is the process of converting information into a form that is meaningless to anyone except holders of a ‘key’.
What is the advantages and disadvantages of common networks, such as Internet
Pros:
- For many people in the modern day world the internet has replaced all other research methods.
- Allowing that you own a credit card, you can buy or sell virtually anything, or book tickets onlines.
- There are countless methods of communicating through common networks: Blogs, social networkings…
- Over the internet you can share programs, downloads, files and software.
Cons:
- To access the internet or any other common network you need the proper resources. –> COSTLY
- If you go ‘shopping’ online there’s a possibility that your credit card number could get in the wrong hands. Personal info can be stolen and accessed unauthorisedly.
- Spam continues to be a problem on the internet and is slowly increasing. You become vulnerable to hackers and virus’ can be spread, putting you computer at great risk.
Some features of email?
Electronic mail or email is a means of sending messages, text, and computer files between computers via the Internet.
Messages are sent digitally from one person to another.
Each email user has an unique address
Define and describe a fax machine
- A fax Literally makes a copy of your documents and send it to the receiver as a hard copy.
- Each fax has a telephone number
Ad/disad of email
Ad: - Little training needed - Free to send - Images can be attached - Usually received very quickly Dis: - Spamming ( 2/3 of all mails) - Viruses - Email scams - Must have access to Internet
Ad/disad of fax machine
Ad:
- As long as it’s switched on, the messages can be sent
- Inexpensive
- Allow extract copies of a handwritten information to be transmitted without it being prepared in a special way
- Little training
Disad:
- Dial wrong number -> Wrong recipients.
- Have same telephone number as telephone -> When it’s in use you cant use the telephone
- Quality is often poor
Define and describe tele/video conferencing
Allow people in different locations can talk and see each other’s live images
Need the applications, an User ID to create a group
Ad/disads of video conferencing
Ad:
- No need to spend money and time to travelling
- View each other at the same time -> Contribute and give out ideas just like a FACE TO FACE conference
- Excellent way of keeping in touch with the family
Disad:
- Even w/ fast internet connection, -> still a slight delay between responses.
- Hardware breaks down, can’t attend the meeting
-Different time zone -> inconvenient -> stay up late, wake up early ..
Why is security needed?
It ensures privacy, data integrity and preventing computer crimes
Physical safeguards
- Access control: Lock the ICT room using codes, srtipe cards -> Only those who are allowed can enter
- Access monitoring: CCTV cameras
- Data security: Regular backups (mayb in another location)
- Protect hardware from fire, floods, disasters and THEFTS
Software safeguards
- USernames and passwords
- Access permission: Access limited to the minimum number of ppl who need it.
- File-level passwords
- Virus scanner
- Firewall
- Transaction logs -> track alterations to the ICT systems
- Data encryption
