A network of computer
networks and computers using a
globally unique address space
based on the Internet Protocol
and TCP/IP to support public
access to email and web pages
ect
(WWW) World Wide
Web is a system of
interlinked, hypertext
documents accessed
via the internet
End to end princible
Two computers control a
communication across the
intenet
Each computer using
the internet should be
uniquely identified
Packet switching
Data packets flow across the
internet between two end points
that control their
communication
A message is broken into variable
length packets consisting of part of
the data, source and destination
adress
The packets travel
independently through the
internet backbone, routed on
the basis of the destination
adress
Routers
Hosts are computers
running applicfations
A router is a special switch that
recieves packets from one host or
router and uses the destination IP
address
Gateways
Connects networks that use
different protocols
Each network is connected to the
internet through a router gateway the
gateway overcomes the mismatch
between different networks
Internet address
Each computer on the
internet is labeled with a
globally unique address
known as an internet
protocol address
The numbering
system IPv4 used today
allows for 232 different
adresses
All these unique addresses
make up a single logical
address space. At a binary
level, an IPv4 address consists
of 32 bits
Domain names/ IP
addresses
Hierarchical system using abbreviations
and names. Examples of top level
domain suffixes include arp,mil ,com,
edu, gov and country names such as .uk
Domain name system
DNS. Watch DNS made
easy
DNS server translates fully
qualified domain name into
an IP address
URI Uniform resource
identifier is an identifier
for a resource.
A URL identifies via its
network location
A URN identifies a
resource from its name
A domain name identifies a network of
computers whilst a fully qualified domain
name uniquely identifies a particular host
on this working
Client server model
Server is software
process that provides a
service requested by a
client software process
A client is a software
process that requests and
uses the services provided
by a server
A client software process
initiates a request for some
service from a server software
process which responds to that
request
Protocols
FTP Uploading
files to a web
server
Telnet logging into
and running
software on a
remote computer
HTTP Hypertext
transfer protocol:
viewing web pages
POP3 downloading
personal emails
from a webmail
server
(Secure) SHTTP
accessing secure
web pages
SMTP sending
emails
TCP/IP
4 layers application,
transport, network
and link
Application
Handles the details of a
particular network link
application
Transport
Establishes supervises and
maintains a connection
between two communicating
applications one on each host. it
ensures a reliable flow of data,
detects when errors occur
Splits data that the
applications wish to
send into chunks to fit
packets and
reassembles recieved
packet data in to data
for application
Network
Addresses packets with source
and destination IP addresses so
that they may be routed through
the internet
Link
Handels all the physical details of
interfacing with the cable including
the network interface card and a
device driver