1.3 Computer Networks, Connections and Protocols Flashcards
Network
Formed when 2 or more computers are linked together in order to communicate + share resources
LAN full form
Local Area Network
LAN
A network covering a small geographical area on a single site
Computers are connected to each other
Who is hardware owned by in a LAN?
By the organisation
Are LANs wired or wireless?
Wired (e.g. using ethernet cables) or Wireless (e.g. using Wi-Fi)
WAN full form
Wide Area Network
WAN
Connects LANs that are in different geographical locations
Example use of a WAN
businesses with offices abroad
Who is hardware owned by in a WAN?
Hire infrastructure
Are WANs wired or wireless?
Wired
What medium do WANs use?
Fibre - Optic
Copper telephone lines
Satellite links
Radio links
What is the biggest WAN?
The Internet
Factors that affect Network Performance
Bandwidth available
Transmission media
Number of users
Network Topology
Choice of hardware
NIC full form
Network Interface Controller
NIC
allow a device to connect to a network. Each one has a unique MAC address
Switches
Connect devices on a LAN. Receives data in frames from one device and transmits the data to the device with the correct MAC address
Routers
Transmits data between networks. Directs data in packets to their destination
Recieves data between networks
Forwards data to their destination
Where are Routers used?
Homes / offices to connect a LAN to the internet
3 types of Transmission Media
Fibre Optic Cables
Coaxial Cables
Ethernet
Fibre Optic Cables
- Transmit data as light
- High performance/no interference =
expensive - Can transmit data over long distances
Coaxial Cables
Single copper wire with plastic insulation and metal mesh (shielding from outside interference)
Ethernet
Most common: CAT 5e, CAT 6
4 pairs of twisted cables -> to reduce interference
Bluetooth
Direct connection between 2 devices
Bluetooth connection range
10m
Bluetooth Bandwidth
Low
Bluetooth uses
Mobile/wearable devices
Wi-FI
For multiple devices to connect to a LAN at the same time
Wi-Fi connection range
40-100m
Wi-Fi Bandwidth
High
Wi-Fi uses
Home
Client - Server
Managed by a server
Files + software are stored centrally
Client - Server Relationship
Clients send requests to the server to access data
What does a client - server server store
Files
Passwords
Example of a client-server relationship
Websites are hosted on web – servers. Web browsers (clients) sent requests to the web – servers to access data
Advantages of a Client - Server
Easy to keep track of files
Easy to perform backups
Easy to install + update software
Disadvantages of a Client - Server
Expensive to setup
Server dependence - if the server is down then all clients lose their work
Server may become overloaded – too many clients access it at once
Peer to Peer
All devices are equal –> connect directly to each other
Where are files stored on a peer to peer
On individual devices
Uses of Peer to Peer
Home to share files between devices/share hardware
Advantages of Peer-to-Peer
Easy to maintain – no expensive hardware
No dependence on server – if one device fails the whole network isn’t lost