Internet & WWW Details

Client-Server Architecture

Browser-WebServer Details

Part 0: Your Project

• Your project is to create a working e-commerce website.

• Here are some feasible project ideas…

Part 1: Internet History & Details

Timeline:

• Innovation Phase: 1961-1974

• Institutional Phase: 1980-1993

• E-commerce Phase: 1995-today

Internet Characteristics

• Analogy: Human Characteristics that really matter:– Humans walks on two legs– Humans have a 3lbs brain.– Humans communicate with speech and

written words

Internet Characteristics

• Internet characteristics that really matter:– Internet uses packet switching –

• data is broken into little packets that have to re-assembled

– Internet uses TCP/IP protocol – • robust protocol for sending everything from email

to video

– Internet used IP addresses

Innovation Phase: 1961-1974

• All the technology was invented– Paul Baran proposed the idea of packet

switching for network communication (1962)– Vinton Cerf Proposed TCP/IP Protocol in

1974

Institutional Phase: 1980-1993

• ARPANet: A purely military network got turned over to Scientists working on Defense Department Projects– National Labs – National Science Foundation– NASA– Department of Energy– Leading Universities

• Over in Europe another large network emerged.– CERN – Leading particle physics lab (Geneva,

Switzerland)

Institutional Phase: 1980-1993

• ARPANet and CERN’s network officially became 100% TCP/IP in 1982

• Standardization – commitment to this standard protocol allowed software developers to coordinate networking efforts.

• In many ways, this marks the birth of the Internet we now know.

Side Topic

• Didn’t Al Gore invent the Internet?

Side Topic

• Didn’t Al Gore invent the Internet?– Al Gore never made this claim…it’s a complete

misquote• Gore’s High Performance Computing and

Communication Act of 1991 (Gore Bill) passed in 1991 and led to the National Information Infrastructure.

• This directly led to the commercialization of the Internet.– The term Internet started to become widely used.– Gore may have been the first to use the term

“information superhighway.”

E-commerce Phase: 1995-today

• Prior to 1995, the Internet facilitated B2B e-commerce (which is really e-business).– But the systems developed were very specialized and

isolated.

• True E-commerce wasn’t realized until the end consumer got Internet access.

• In 1995, we saw the explosion of Internet Service Providers (ISPs)– AOL– Dialup Providers

ISPs of Today

• Telephone companies own most of the infrastructure. They are the global players– They farm it out to local ISPs

• Cable TV providers are now the biggest local players.

• Dialup Still exists– AOL– Netzero

Part 1: Internet History & Details

• Network of networks built on standardized technology and protocols.

• Until the Internet emerged…different groups were using all different kinds of protocols.

• Key Term: Protocol– a set of rules governing the format of

messages that are exchanged between computers

Packet Switching

• PAD – Packet assembler/dissembler

Why is Packet Switching important?

• Otherwise you need a direct, uninterupted connection, which is not feasible.– Network goes down all the time.– Traffic gets re-routed on the fly

• Also, its higher performance.– Your packets could take numerous paths in

parallel.

TCP/IP• Transmission control protocol

• Internet Protocol

Why is TCP/IP so important

• The Internet would never have expanded so rapidly without a commitment to Global Standardization

• Its hard to get experts to agree on a single Protocol

• TCP/IP is very robust and allows for numerous levels of sub-networks.

IP Address

• 32-bit number– Uniquely identifies devices on the Internet

• 192.168.120.227– 4 billion unique devices.

• There are already more than 4 billion devices:– Sub-netting –

• one IP address gets you to a subnet• Subnet uses its own internal IP address.

Sub-Networks

• IP Addresses are a commodity, limited supply.• Controlled by ICANN, which indirectly came from

the Gore Bill.• Siena gets Internet Access from Time Warner

Cable…we probably pay for 20-40 IP Addresses, which are reserved for key server– Web server– Blackboard server– Mail server.

• How do the other 4000 computers communicate?

Internal Sub-netting

• Outside of Siena, you can’t reach computer A and B directly.

• Instead, you contact the router(Real IP) and also indicate A or B’s Internal IP.

Internet (All Real IPs in

the World)

Siena Gateway Router (Real IP)

Time Warner (Real IP)

Internal IP

Internal IP

A

B

Internal Sub-netting

• Siena’s router is programmed so thatA and B can directly communicate using Internal IPs (sub-net).

• If A needs to reach a computer C outside of Siena, then the routermodifies the packet headersto indicate the Siena Router’sReal IP address and the Internal IP of A.

• Thus, C will knowhow to reach A.

Internet (All Real IPs in the

World)

Siena Gateway Router (Real IP)

Time Warner (Real IP)

Internal IP

Internal IPA

B

C

Part 1: Activities

• Traceroute

• Lookup

• Whois

• Ping

• Finger

• Port Scan

Part 2: World Wide Web (WWW)

• Remember: There are companies that use the Internet to connect two computers, yet these computers are not part of the WWW.

• To be part of the world wide web, you need a URL– Uniform Resource Locator (not universal)

URL examples

• mailto:ebreimer@siena.edu

• http://www.cs.siena.edu

• ftp://ftp.mit.edu/public/data.db

URL Concept

• Internet IP Address are meaningless– There is no organization– No geographic significance– No organizational significance

• Create a meaningful name that is an alias for an IP Address– Given a URL create a system to find the IP

Address (DNS lookup).

URL Breakdown

• http://www.cs.siena.edu

Protocol

Server Name

Sub-Network (optional)

Main Network – Domain Name

Top Level Domain Name

Top-level Domain Names

Top Level Domains• .com• .net• .org• .edu• .mobi• .gov• .mil

• U.S. - centric

• Country Domains• .cn• .ca• .de• .au

• Combinations• .com.au• .edu.au

Domain Name Hierarchies

root Name Server (NS)

.com NS .edu NS .net NS

siena.edu NS mit.edu NS harvard.edu NS

www.siena.edu cs.siena.edu NS sos.siena.edu NSimail.siena.edu

www.cs.siena.edu ares.cs.siena.eduturing.cs.siena.edu

Domain Name Hierarchies

ICANN

• Internet Corporation for Assigned Numbers and Networks.

• Global coordinator of IP Address and Domain names.

• Registrars like GoDaddy are “licensed” by ICANN to register domain names.

• Large Internet Providers (ISPs) also “secure” IP addresses and farm them out to smaller ISPs.

Map of the Internet (US)

• http://www.cs.siena.edu/~ebreimer/courses/csis-116-s07/Internet_map_labels.pdf

• The above is a partial map as seen from one location (Lumeta.com).

USA: Pioneers of the Internet

• The United States pioneered the Internet, and thus, “owns” the largest chunk of the infrastructure.

• Western Europe, Japan, and Australia were quick to follow.

• Eastern Europe, Russia and China are just getting established

• Parts of Asia are next: India • South America is coming along• Africa may be decades away

Part 2: Activities

• Do some surfing and try to find a URL with a sub-domain.

• How much does it cost to register a domain name for .com, .net, .us?

• Thinking of registering a domain name for your project? See if the one you want is available?

Client Server Model

• The WWW uses this model exclusively.

Protocols of the WWW

• HTTP / HTTPS – Hypertext Transfer Protocol (Secure)

• FTP / SFTP – (Secure) File Transfer Protocol

• SMTP – Simple Mail Transfer Protocol

• POP – Post Office Protocol

• IMAP – Internet Message Access Protocol

• Telnet – Terminal Emulation

Big Picture

Host MonsterWeb Server

Utah Internet

Clients / VisitorsPotential CustomersPotential Revenue

USA

AlbanyOther countries?

You – The Developer / The Designer

HTTP / HTTPS

FTP / SFTP

Big Picture

Host MonsterWeb Server

Utah

Internet

Clients / VisitorsPotential CustomersPotential Revenue

You – The Developer / The Designer

HTTP / HTTPS

FTP / SFTP

•HTML Documents (Production)

•Application Support Services

•Message Board Service

•Payment Systems, Chat Server,

•HTML Documents (Development)

•HTML Editor

•Image Editor

•Other Development Software

Big Picture

Internet

Hostmonster Server

You – The Developer / The Designer

HTTP / HTTPS

FTP / SFTP

•HTML Documents (Development)

•Steal other websites designs

•HTML Editor

•Dreamweaver

•Image Editor

•Fireworks

•Other Development Software

•Flash

•Word

•ExcelHostmonster Control Panel

FTP, SFTP, or SCP Client

Key Technologies

• Hypertext – – HTML – Hypertext Markup Language

• Markups are used to structure a web page

– CSS – Cascading Style Sheets• Styles are defined that decorate each structural

element

DNS

Domain Name System

• The WWW is supported by a network of DNS servers

• These server help translate URLs into IP Addresses.

• Domain Names are a fundamental concept that is connected to E-commerce.

Why are Domain Name so important?

Setting up a web server

The old way

• Buy a computer (The Web Server)

• Get an static IP Address from your ISP

• Install Web Server software

• Register a domain name with ICANN

• Have your ISP update their DNS server.

Setting up a web server

The NEW way

• Buy a computer (for creating web pages)

• Pay for hosting service (Web Server + DNS services).– Get the name of the DNS server.

• Register a domain name with Registrar– Tell the registrar the name of the DNS server

that your hosting service is using.

DNS Services vs. Hosting

DNS Services• ICANN coordinates this

effort (1st party)• Companies (2nd party)

need domain names.• 3rd parties registrars

actually manage domain name registration.

• Registrars: goDaddy, Network Solutions, Yahoo

• Hosting Services