topic 5: communication and the internet

WAN

uses satellites and radio waves to connect and usually spreads over a a wide geographical area

internet

a collection of inter-connected networks

WWW

a method of accessing information on the internet

HTTP

the protocol governing the transfer of hypertext web pages across the internet

ISP

internet service provider provides access to the internet for private individuals and businesses

web servers

stores and distributes web pages

URL

a web address

DNS

translates domain names into IP addresses

wired vs wireless

LAN

covers a relatively small geographical area

advantages and disadvantages of networking

PAN

a network communicating between computer devices

bandwidth

the amount of data that can be carried at a time

bus

ring

star

mesh

router

sends data packets on their way in the best direction

hub

when a packet of data is received, it broadcasts the packet to all devices on the network

switch

send packets to the intended recipient using its mac address

advantages of a client server

all data can be backed up centrally

security is better as data is held in one location

users can log in from any computer on the network

advantages of peer to peer

easier to set up

no special software is requires

individual computers share a printer, router, modem and other hardware

users can communicate directly with each other and share each others’ files

drawbacks of peer to peer

viruses and malware are easily transferred over this type of network

data recovery and backup is not done centrally

packet header

contains packet number, total number of packets in the transmission, source address, destination address

SMTP

protocol for sending emails between servers

POP

holds email for individual until picked up then deletes it from the server

IMAP

stores emails on a server so it can be accessed and edited from anywhere

TCP

how messages are broken up into packets and reassembled at the destination

TCP/IP protocol stack

application

transport

network

link

application layer

encodes data sent so it can be understood be recipient (FTTP or FTP)

transport layer

sets up communication between two computers

network layer

attaches the IP address of the sender so the recipient will know who sent it

link

the physical hardware that connects the two hosts

physical security

controlling access to critical parts of a network using physical methods

malware

malicious software designed to disrupt the use of a computer system

social engineering

the art of manipulating or conning individuals into giving away private information

phishing

a trick email the seems legitimate that tricks user into giving up personal data

shoulder surfing

direct observation of a user entering their security details

software patch

an update to a program to improve it or fix a bug

DoS attack

attempts to flood a website server with an overwhelming number of data requests