Networks Flashcards
WAN (Wide Area Network)
An area connecting LANs over a large geographical area
NIC (Network Interface Card)
Formats data from a computer according to the protocols of the network
Copper cable
- carries electric current
- cheap
- lower bandwidth
Fibre optic cable
- pulses of light
- more expensive
- higher bandwidth
Bandwidth
The measure of how much data that can be transferred every second
WAP (Wireless Access Point)/ or router
Allows wireless devices to connect to a wired network using wifi
Wired Network
- high bandwidth
- expensive for cabling
- security is good
- not mobile
- no interference
Wireless network
- low bandwidth
- cheap
- poor security
- signal can be affected by walls or congestion
- very mobile
Topology
The physical layout of computers on a network.
Bus topology
- less cable length
- can be set up quickly
- security risks (everyone can see)
- if cable breaks then all will be affected
Star topology
- Less traffic
- Security is better
- One link fails the rest will work
- Depends on server to be working
- More cable needed
IP address
A set of numbers used to identify one particular device
Domain name
The name that identifies a Web site.
Packets
A small block of data transmitted from one computer to another
Header (packets)
Contains source and destination
Body (packets)
Contains part of the complete message data
Footer(packets)
Informs device it has reached the end of packet and checks for errors
How data transmits
- Source computer splits file into packets
- Packets sent using cables or microwaves
- Routers inspect packet and decide best route
- If there is a problem with network the packets will be diverted
Packet switching
Message broken down and sent over more suitable routes (assembled at the end)
Protocols
Set of rules in order to perform and action
TCP/IP
Transmission Control Protocol/Internet Protocol
Application layer (1st)
Selects correct protocol based on what you are trying to do
Transport layer (2nd)
Creates link between two people and divides packets up
Network layer (3rd)
Sends and routes the data
Link layer (4th)
Transmits data to the computer itself (through cable normally)
FTP (File Transfer Protocol)
Rules followed when files are transferred
POP
Post Office Protocol
IMAP4
Internet Message Access Protocol v4 used to retrieve emails from a server
Benefits of separate layers
Layers can be developed independently without any knowledge of other layers
