A global, public network of computer networks. The largest computer network in the world. Computer Network A collection of computing devices connected.

InternetA global, public network of

computer networks. The largest computer network in

the world.Computer Network

A collection of computing devices connected to share resources such as:

FilesSoftware

ProcessorsStorage

and printers

Internet technology and the physical connections between devices support many applications…..

Such as…. E-mail and the Web.

E-mail: Provides a convenient and low-cost form of communication over the internet.

Web:Provides a convenient method of sharing information and services.

Web = Internet ??

InternetProvides the technological infra-structure on

which the Web and other Internet-based services depend.

WebProvides a convenient platform for delivering information and services using the Internet

CommunicatingSharingLearning

Finding entertainmentMaking new friends

Internetwork

Networks joined together into larger networks so that users on different networks can communicate

and share data’s Intern

Today’s Internet joins together networks of over 500 million computers (or Internet hosts) to create

the world’s largest internetwork

Digital Divide:The difference between those that have access to

the internet and those that don’t.

The Internet is a combination of hardware, protocols, and software.

Hardware :provides the physical cables and devices that

control and carry Internet data.

Protocols: the rules that are implemented in network software and hardware to establish connections between two or more computers to allow them to communicate.

Software:Allows users to interact with the Internet to access

information and services.

Network Service Providers:

A company that provides backbone services to an Internet service provider

The Internet backbone refers to the principal data routes between large, strategically interconnected

networks and core routers in the Internet.

It is made up of many national and international communication networks that are owned by major telecom companies such as AT&T and Sprint.

These companies agreed to connect their networks so that users on all the networks could share information over the Internet.

Network service providers enable Internet users to connect to their networks through utility stations

called “points of presence” (POPs)

The POP’s act as the hubs, and the connections they provide, the spokes.

INTERNE

T

Users connect to the Internet through an Internet Service Provider (ISP)

Which connects to the network service provider (NSP)

through a point of presence (POP)

ISP

POP

NSP

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Bandwidth?• Bandwidth

o is the transmission capacity of a communications channel

• Broadband o high-bandwidth communications systems

• Narrowband o Systems with less capacity

Note:The bandwidth of a digital channel is usually measured in bits per second (bps).

TCP/IP Transmission Control Protocol/Internet Protocol

Policies and procedures for transmitting over the internet.

Data Packet

Small group of bytes that includes the data being sent and a header containing information about the data, such as….

destination origin size identification number

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• Internet Protocol (IP)• The Internet Protocol (IP) defines the format and

addressing scheme used for the packets

• All devices connected to the internet have a unique IP Address

• IP Address: a unique 32 bit identifier for internet hosts.

• Static: permanently assigned to a particular computer

• Dynamic: assigned to computers as needed.

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Internet ProtocolsProtocols make the internet possible

• TCP/IP provides a standard that is fairly easy to implement, public, free, and extensible

• The Internet is not owned, operated, or controlled by any single entity

• TCP/IP is glue that holds the Internet together

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IP Addresses

• The IP part of TCP/IP defines the format for the addresses that identify computers on the Internet

• These addresses are called IP addresses• An IP address is a series of numbers, such as

204.127.129.001o It is separated into four sections by periodso Each section’s number cannot exceed 255o Each address requires __ bits (8 bits per section)

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Domain Names• People find it difficult to remember long strings of

numbers, so host computers also have names called domain names

• Domain name – “fully qualified domain name” (FQDN), usually typed in all lowercaseo Key component of URLs and e-mail addresseso www. msu.edu/biologycatalog.htm - www.msu.edu is the

domain name

• A domain name ends with an extension that indicates its top-level domain

Disputes

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Domain Name → IP Address

• Each name corresponds to an IP address

• Domain name system – Huge database that houses the names and IP addresses

• Domain name servers – Computers that house the database

Internet Software

• Two basic architectures:o Client/server

Client makes a service request Server provides the service Port

Logical addresses on the server

Client/server technology is the basis of Internet services such as e-mail and the Web and uses server computers to distribute data to client applications such as Internet Explorer

o Peer-to-peer (P2P) networking Facilitate communications directly between clients

Peer-to-peer Networking

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The protocol of the Web is called HTTP

Hypertext Transfer Protocol (HTTP) – controls communication between Web clients and servers.

A Web client is commonly called a Web Browser.

Markup LanguagesA markup language is used to describe how information is to be displayed.

The primary markup language that is used to specify the formatting of a Web page is called Hypertext Markup Language (HTML)