What is the Internet?

A network of network, joining many government university and private computers together and providing an infrastructure for the use of E-mail, file archives, hypertext documents and other computational resources.

Contd…

•Computers on internet have a unique address - IP address

•Network of networks connected using a common communication protocol (TCP/IP)

Contd…

The internet is a global network of computers and computer network communicating under one set of guidelines, formally called Transmission Control Protocol/ Internet Protocol (TCP/IP)

How internet works?

Protocols – standardized rules that define how computers communicate and

exchange dataIP address – unique number used to identify

computers on internetDomain name – structured naming system to locate

computers on the internet

Contd…

URL – uniform naming scheme that specifies unique address of

internet resourcesClient and Server – computing architecture used

by most internet services

Contd…

TCP/IP The internet is a packet switching network that

uses TCP/IP as its core protocol TCP/IP is a suite of protocols that govern network

addresses and the organization and packaging of the information to be sent over the internet

• TCP-flow control $ recovery of packets

• IP – addressing and forwarding of individual packets

Internet protocols

HTTP – for accessing and transmitting World Wide Web documents

FTP – for transferring files from one computer to another

Gopher Protocol – for accessing documents via Gopher menuTelnet Protocol – allows users to login to a remote computerSMTP (Simple Mail Transfer Protocol) for sending and managing

electronic mails(e-mail)

IP address

IP address is a unique address assigned to each computer connected to the internet

It is used by TCP/IP to route packets of information from sender to a location on the internet

IP address consist of four sets of numbers ranging from 0 to 255

E.g. -249.7.13.53

Contd…

The first two numbers set designate the networkThird number set identifies local networkFourth number set identifies the particular machine

IP VERSION

There are two versions of IP:-

IPV4 e.g. 172.16.254.1

IPV6 e.g. 2001:db8:0:1234:0:567:8:1

TYPES OF ADDRESS

Static Address

Dynamic Address

contd….

Static Addressmanually input by network administrator.

manageable for small networks .

requires careful check to avoid duplication.

Contd…

Dynamic Addressassigned on LANs and broadband networks by DHCP servers.

derived automatically from the range of addresses.

Various forms of IP Addresses

Decimal system with base 10.

Domain name system-By it own name.

DWORD format - Decimal number system.

Octal system - Base 8.

Hexadecimal - Base 16.

A cross breed – Combination of above two.

Domain names

Domain names are the alias or English language equivalent of computers IP addresses.

DNS allows the use of easier to remember domain names instead of IP addresses to locate computers on the internet

Domain Name resolvers scattered across the internet translate domain names into IP addresses

Contd…

Domain names have two parts: First part names the host computer Second part identifies the top level domain

Top level domains – identify the type of host Country Code Top Level Domains Generic Top Level Domain

Domain names are used in URLs and email addresses

Top Level Domains

.com - commercial/company site edu/ac - educational/academic .gov - government site .org - non profit organizations .mil - military sites .int - international organizations .net - network providers

Additional Top level Domains

.aero - restricted use by the air transportations industry

.biz - general use by businesses.coop - restricted use by cooperatives.info - general use by both commercial and

non commercial sites.museum - restricted use by museums.name - general use by individuals.pro - restricted use by certified professionals

DNS Tree

Working of D N S

References

http://docs.google.com/viewer?a=v&q=cache:FnTcI0XJmEEJ:ncsi-net.ncsi.iisc.ernet.in/gsdl/collect/drtbrara/index/assoc/HASH013c.dir/doc.pdf+how+internet+works+powerpoint+slides&hl=en&gl=in&pid=bl&srcid=ADGEESi6fDmD9nO_XELgDSjgiNFF3Duykwg-JBhmAfs0o3D0BR44y0Mp9lK56t49PQnasU2or-zdJ7DMP6Bh0ybYsjFDqdnhd4unAZ_nh9t5aQ5eLxSs9eFltpRyFFNYRbl1grJcMU0r&sig=AHIEtbSqRDv8P6M54mJUR1TOoTi_jhGnfw

http://docs.google.com/viewer?a=v&q=cache:9hD-3eQQs0UJ:www.computing.dcu.ie/~cgreene/ca106/notes/HowtheInternet.ppt+how+internet+works+powerpoint+slides&hl=en&gl=in&pid=bl&srcid=ADGEESi-9kJU4MrHQBXjDbsoW8L97ttwny5rNKVCwSjib91RS9I-yP0gMxGkelwQoE1hmtK9NoQMYSpnEQyKrf2TYzNe-sngCscU3gwQj37s1OaLYJQ2GkYFMDRpcAhm25BlWdgbB_tn&sig=AHIEtbScRWmHddKr60VvtR8vW0cMvVW_UQ

http://docs.google.com/viewer?a=v&q=cache:9xCE8oicMvUJ:www.doc.ic.ac.uk/~rcheung/teaching/1720/ppt/lecture02.ppt+how+internet+works+powerpoint+slides&hl=en&gl=in&pid=bl&srcid=ADGEESjB45G4E1OBmN894EB4Slc8hSF1oRl4y62hNQn-Sv8_35BJLLSvoalC6CjfGlB_Nlm7WyelgDpB49mixBOzJEY-zgcs4M4dNZOHuym3n3fDqbz9uiTTmQOo2wdgfV0_Phop-mMq&sig=AHIEtbTxpgdFbDf8S2NKXzuwPdcT6JcMQw

http://docs.google.com/viewer?a=v&q=cache:YPV-0ClI1p8J:www.ietf.org/proceedings/64/slides/protut-0/protut-0.ppt+how+dns+works+in+internet-ppt&hl=en&gl=in&pid=bl&srcid=ADGEESjucPpujwzUYPzw5T802Gd8hLeHC1B5NwNdf9ITHvYQijH62vItw9fEOwLuTYzmUdCcDkpfCSx72WXy4qD31-BJs0_eY9OpO3ZhxMARh3z5_dCpMMcbReTa6fiLb6KKbkBer4hk&sig=AHIEtbS-VeUoAoIYmRAHnVINugpQIiPPuQ