Networks THEORY flashcards

Interconnection of computers and other pieces of hardware to facilitate communication and the sharing of resources

• Resources such as printers, internet connections and files can be shared (saving money and effort) • Communication (over email, instant messenger) • Backing up data to a different computer is straightforward

• Managing networks are expensive, and require specialist skill • Security procedures are necessary to prevent unauthorised access

PAN - devices owned by a single user connected via Bluetooth LAN - network covering small geographical area, e.g. single building, hardware owned by a single cooperation or person WAN - covers a large geographical area, with shared ownership of some hardware (e.g. internet)

• more secure (physical connection is needed within the ‘building’ for hackers • less prone to interference • high bandwidths, so lots of ppl can be connected at same time

• much easier to add a device • portable • not very secure • prone to interference • low bandwidths

Optical fibre cabling - very fast connections, able to handle lots of computers sharing same connection copper cabling - cheaper, slower, quick enough for most activities single computer would perform online

Radio waves (connection medium)

Pattern in which hardware on a network is positioned, including connections

Where every device is connected to a switch, at the centre of a network. - Very few data collisions (each device has dedicated line) - Strong centralised security - one workstations failing has no effect on functionality • lots of expensive cabling • adding devices needs expert

Backbone (Central cable) running between 2 terminators, connecting all the devices - uses relatively less cabling (inexpensive) - additional devices can be added easily - collisions can occur, multiple transmissions on shared backbone - large number of devices, means slower transmissions - low security, ‘eavesdropping’

a set of rules that govern how a computer communicates on a network.

-Family of protocols - Set of rules that govern how data is formatted for transmission across LAN

-Brand name (family of related protocols) - rules control how data is transmitted on a WLAN

• two protocols work together • Transmission control protocol and internet protocol -collective role is to break data into packets, that knows where to be delivered and where it was sent from

• user datagram protocol • transmits data packets very quickly • doesn’t check to see whether each packet arrived, unreliable

Hypertext transfer protocol - governs how hypertext (language of world wide web) is moved around the Internet, from device to device

HTTP secure - encrypts data sent across the internet - favoured when sending passwords, credit card num etc.

File transfer protocol - how files are moved from one computer to another across internet - relied upon in building websites, and moving files from developer computer to server, where it can be accessed quickly

Simple mail transfer protocol - POP3 To retrieve emials - sends emails from one server to another

email protocol allows multiple devices to access same email address

Internet Protocol Address, a unique number, to identify every device connected to Internet.

• authentication • firewall • MAC address filtering • encryption

the scrambling of data using a key, so only the recipient can decrypt and read the data.