1.3 computer networks, connections and protocols Flashcards
LAN (local area network)
-small geographic area
-all hardware is owned by the organisation using it
-wired with UTP or fibre optic cable or wireless using routers and Wi-Fi access points
WAN (wide area network)
-large geographic area
-infrastructure is hired from telecommunication companies who manage it. Connected with telephone lines, fibre optic cables or satellite links
client-server network
-a client makes requests to the server for data and connections.
-A server controls access and security to one shared file store
peer-to-peer network
all computers are equal and serve their own files to each other. Each computer is responsible for its own security and backups and usually has its own printer
wireless access point
hardware that allows a Wi-Fi-enabled device to connect to a network
router
-sends data between networks
-it is needed to connect a LAN to a WAN. It uses the IP address on a device to route traffic
switch
-sends data between computers on a LAN
-it uses the NIC address on a device to route traffic
NIC (network interface card/controller)
hardware that connects a computer to a network
transmission media
-physical media that can be used to transmit data
-e.g. twisted copper wire cable, fibre optic
DNS (domain name system)
-the internet equivalent of the phone book
-maintains a directory of domain names and translates them to the internet protocol addresses
Hosting
-websites are stored on dedicated servers
-used for websites that need to be available 24/7, be accessed by thousands of users at one time, be well protected from hackers and have an IP address that doesn’t change
The cloud
-remote servers that store data to be accessed over the internet
-access anytime, anywhere from any device
-automatic backups
-collaborate files easily
web server
-a program that uses HTTP to deliver web pages to users. Page requests are forwarded by a computer’s HTTP client
-dedicated computers and appliances may also be referred to as web servers
client
a device that requests and/or uses services from a remote/connected server
network topology
-the physical or logical arrangement of connected devices on a network
-e.g. computers, switches routers, printers servers
star topology
-computers connected to a central switch
-if one computer fails, no others are affected. If the switch fails, all connections are affected
mesh topology
-switches/routers connected so there is more than one route to the destination
-e.g. the internet. More resilient to faults but more cable is required
wired connection
-any computer network that predominantly connects hardware via physical cables
- e.g. copper, fibre optic
ethernet
-a standard for networking LAN using protocols. Frames are used to transmit data.
-a frame contains the source and destination addresses, the data and error-checking bits.
-uses twisted pair and fibre optic cables. A switch is used to connect computers
wireless connection
-any computer network that predominantly connects hardware via Wi-Fi, eliminating much of the need for physical cabling
Wi-Fi
wireless connection to a network.
-requires a wireless access point or router.
-data is sent on a specific frequency. Each frequency is called a channel
Bluetooth
-a method of exchanging data wirelessly over short distances - much shorter than Wi-Fi
encryption
-encoding readable data into unreadable data
-only the intended recipient can decode the data using a special key.
-protects sensitive communications against hacking
IP address (internet protocol address)
-a unique as string of numbers separated by full stops.
-identifies each computer using IP to communicate via network
MAC address (media access control address)
used as a unique identifier for most network technologies including Ethernet and Wi-Fi
standards
-various rules for different areas of computing
-standards allow hardware and software from different manufacturers to interact with each other
protocol
a set of rules that allow two devices to communicate
TCP/IP (transmission control protocol/internet protocol
TCP provides error-free transmission between two routers. IP routes packets across a WAN
HTTPS (hypertext transfer protocol)
-encryption and authentication for requesting and delivering HTML web pages.
-used in websites that are sending and/or receiving sensitive data
FTP (file transfer protocol)
used for sending files between computers, usually on a WAN
POP (post office protocol)
used by email clients to retrieve email from an email server
IMAP (internet message access protocol)
used by email clients to manage remote mailboxes and retrieve email from a mail server
SMTP (simple mail transfer protocol)
sends email to mail server
protocol layering
the concept of protocol rules being built up in layers - the layered protocol stack facilitates the various rules being executed in defined order
