Fundamentals of communication and networking

serial transmission

Data is transmitted one bit at a time down a single wire

parallel transmission

data is transmitted several bits at a time using multiple wires

bandwidth

the range of frequencies that can be transmitted down a communication channel

what is bandwidth measured in?

Hz

bit rate

the frequency at which data can be transmitted

what is bit rate measured in?

bits per second

baud rate

the number of signal changes per second

what is the relationship between bandwidth and bit rate

bit rate is directly proportional to bandwidth

latency

the time delay that occurs between the data being transmitted and received

asynchronous data transmission

data is transmitted between two devices that do not share a common clock signal

what is the purpose of a start bit

To start the receiver clock ticking and to synchronise the clocks of the transmitter and the receiver

what is the purpose of a stop bit

allows the start bit to be recognised and provides time for the receiver to process the received data

synchronous data transmission

data is transmitted where the pulse of the clock of the sending and receiving devices are in time with each other. The devices may share a common clock

what is a protocol

a set of agreed rules for data exchange between systems

http

hypertext transfer protocol, protocol governing teh exchange of the different types of file that make up displayable web pages

ftp

file transfer protocol, protocol for handling file uploads and downloads

Local Area Network, LAN

A network over a small geographical area

Wide Area Network, WAN

A network over a large geographical area

physical topology

the way in which devices in a network are physically connected

logical topology

the conceptual way data is transmitted around a network

client-server

a network where one device has the main processing power and storage and the other devices act as clients requesting services from the server

peer-to-peer

a network where all devices share resources between them rather than having a server

WWAN

Wireless WAN, a WAN that does not use cables so sends data using radio waves

MAC address

Media Access Control address, a unique code that identifies a particular device on a network

WiFi

a standard method for connecting devices wirelessly to a network and to the internet

WLAN

Wireless LAN, a LAN that does not use cables but connects using radio waves