Fundamentals of Computer Networks Flashcards
What is a computer network?
Two or more interconnected computers - may be connected either wired or wirelessly.
What are the benefits of computer networks?
- Communication is easier
- Can use computers anywhere in the world to access their info (if stored on a network)
- Easier to store files and info over a network
- Easier to share resources
What are the risks of computer networks?
Expensive hardware
Risk of viruses + hacking
Specialist staff often required (setting up complicated network).
(Dependence) users relying on a network might be stuck without access to it.
Describe what a Personal Area Network is.
A personal area network is that is used for data transmission amongst devices.
Describe what a Local Area Network is.
A local area network is a network of computers within the same building.
Describe what a Wide Area Network is.
A wide area network is a network that spans across a building, buildings or countries.
What is a wired network?
Computers can be connected through Ethernet cables which connect to the Ethernet port.
What is a wireless network?
A wireless connection that uses radio signals to send data across networks.
What are the benefits of wireless networks as opposed to wired networks?
Users can move around freely within the area of network with their devices and get an internet connection.
Users can share files and other resources connected to the network without being connected to a port.
Saves expense, time and inconvenience of having to lay cables.
Easier to add new device as no new cabling is required.
Instant transfer of data is quicker.
What are the disadvantages of wireless networks as opposed to wired networks?
File transfer speeds are generally slower
Can be obstructed by walls, ceilings and furniture
Are generally less secure and easier to hack into
Explain the star topology.
When all of the computers have their own cable connecting them to a switch, which routes messages to the correct computer. A powerful computer called the server controls the network.
Explain the bus topology.
Computers are connected to a single backbone.
They all share this cable to transmit to each other and each message is divided into frames.
What is a protocol?
Set of rules that define how devices communicate.
What is a Network Interface Card?
All devices connecting to the internet need an NIC.
What is a Network Interface Card?
All devices connecting to the internet need an NIC. Required to connect any network-enabled device. It is a physical component which can either operate wirelessly or have a wired connection using a standard Ethernet cable.
What is a MAC address?
Each NIC had a unique media access control, which is assigned and hardcoded into the card (by manufacturer) and uniquely identifies device. Address is 49 bits long and written as 12 hex digits.
What is Wi-Fi?
Wireless fidelity is a family of protocols or rules that make wireless networking run smoothly.
What are the risks of wireless networks?
Criminal activity - an unauthorised user can use the wireless connection to hack into the network and cause damage by planting viruses, or bring the network to a halt by flooding it with useless traffic.
Bandwidth stealing - outside intruders slow the network down by using the internet to download games, music + other software.
Confidentiality - if any network infor isn’t encrypted before transmission, an intruder can gain access to confidential info.
What is Ethernet?
Family of networking rules/protocols widely used in LANs.
What is the Ethernet protocol?
Describes how devices should format data ready for transmission between computers on the same network. Used to change the format of data if it is not in the right format.
- Nodes wait until connection is quiet, then attempt to ‘speak’ or transmit.
- 2 nodes attempting to transmit simultaneously stop and wait a random period before reattempting.
Explain the purpose and use of the Wi-Fi protocol.
Allows electronic devices to connect to a wireless LAN. Wi-Fi compatible devices can connect to the Internet via a WLAN and Wireless Access Point (WAP).
How does the Wi-Fi protocol work?
WAP receives data from network via its physical location.
Transmitter converts data into radio waves which are then transmitted.
Any device on network receives this radio signal via a Wi-Fi adaptor - allows it to communicate or download data from data source.
Works in reverse direction when device wishes to send data over network to another computer.
Explain the purpose and use of the TCP (Transmission Control Protocol) protocol.
A standard that defines how messages are broken up into packets and reassembled at the destination. Also detects errors and and resends lost packets.
Explain the purpose and use of the UDP (User Datagram Protocol) protocol.
Uses a simple connectionless transmission model and an alternative to TCP, but has no error checking or correction.
