Chapter 2 – Technology Infrastructure

This chapter explains the origin of the internet and the events that have made the internet what it is today. The author also goes into depth about the components of the internet and the developments that have occurred over the past years to improve its efficiency. Networks, protocols, connections, e-mail, and markup languages are touched on and explained. In addition, Internet2 and the Semantic Web are discussed to present a picture of the future of e-commerce.

The Internet and the World Wide Web
A computer network -technology that allows people to connect computers to each other
Internet: connects computer networks around the world
World wide web: subset of the computers on the internet that are connected to each other

Origins of the Internet
-1960s- US Defense concerned about nuclear attacks on facilities wanted coordinated system and looked for ways to connect computers
-Defense was concerned about risk of a single telephone channel and developed a multiple channel system that allowed files to be broken into packets that were labeled electronically with codes of origin, sequences, and destinations.
-In 1969, Defense Department researchers (Advanced Research Projects Agency) connected 4 computers into a network - ARPANET.
-1972- first email system was developed by Ray Tomlinson
-1974- TCP/IP – Vint Cert known as the grandfather of the internet developed protocols (common language, rules for transferring data)
-1979- Usenet was developed to provide a news group network – email for groups
-1980s-National Science Foundation (NSF) funded by government - provide access to the resources of the government
-1991 the NSF (national science foundation) eased restrictions on commercial internet use to privatize internet completed in 1995 when NSF turned the main internet connections to a group of privately owned firms- new structure based on four network access points
-Network access providers-sold internet access to large customers and indirectly to smaller firms through internet service providers.
-Internet hosts-computers directly connected to the internet.

Emergence of the WWW
-web-software on computers connected to the internet. Two key elements of the web: hypertext and graphical user interfaces
-1945: Vannevar Bush – wrote a book that talked about a machine (Memix) that stored memory items that could be retrieved
-1960s: Tex Nelson created the term hypertext
-Hypertext: text on one page links to text on another
-1989-Tim burners-lee (father of the web) - hypertext to provide data sharing and developed a code for hypertext server-a computer that stores files written in hypertext markup language and allows computers to connect and read filesà aka web servers.
-Hypertext Markup Language (HTML): language that includes a set of codes attached to text and graphics that describe the relationships among text. Hypertext link/hyperlink points to another location in the same or another document
-Web browser: software to help read HTML documents and move among documents through text formatted with hypertext link tags. Presents HTML documents in an easy to read format.
-1993: Mosaic – first web browser
-1994: Netscape (formed by the merger of Andreesen and Clark)

Packet Switched Networks
-Local area Network: network of computers that are located close together
-Wide area Network (WAN): networks of computers connected over greater distances-early models were circuits of phone companies.
-Internet uses packet switching network to move data between two points -files are broken down (packets) labeled electronically with their origins, sequences, and destination addresses and travel along interconnected networks until they reach destinations.

Routing Packets
-Routers: decide best method to get packets to where they need to be- connect networks. Include rules called routing algorithms
-Network devices that move packets from one part of a network to another - hubs, switches, and bridges. When packets leave a network to travel on the internet they must be translated into a standard format. Routers perform this.
-Internet has routers that handle packet traffic along main connecting points- internet backbone

Internet Protocols
-A protocol -collection of rules for formatting, ordering, and error checking data sent across a network. Two main protocols: Transmission Control Protocol -controls disassembly of a file into packets before transmitted over the internet, controls reassembly of packets into original formats at destinations.
-IP specifies details for each packet, labeling each with origin and destination addresses.
o Internet Protocol version 4 (IPv4)-uses a 32 bit number to identify computers connected to the internet.
o Subnetting-stretch the supply of IP addresses-the use of reserved private IP addresses within LAN/WANs to provide additional address space. Private IP addresses-IP numbers not allowed on packets that travel on internet. Network address translation (NAT) device converts private IP addresses into normal addresses when packets travel over internet.

Domain names
-Top level domain: .com. since 1998, the internet corporation for assigned names and numbers has been responsible in managing. Sponsored top level domain: organization other than ICANN is responsible.

Web page request and delivery protocols
-Web client computers send requests for web page files to web servers which receive requests and sends files back. Web client computer’s software transform files into webpages. Purpose of a web server is to respond to requests for web pages from web clients.
-The set of rules for delivering web page files over the internet is in a protocol called the hypertext transfer protocol (HTTP). The combination of the protocol name and the domain name is called the uniform resource locator.

Electronic Mail Protocols
-Simple Mail transfer protocol specifies format of a mail message and describes how mail is administered and transmitted on internet.
-Post office protocol -tell email server to send mail to user’s computer and delete it
-Interactive Mail access protocol-newer, similar to POP but includes more features -don’t have to download messages to computer)

Markup Languages and the web
-Text markup language: specifies a set of tags inserted into text, provides formatting instructions that web software can understand to turn text in the files into web page.
-Standard Generalized Markup Language (SGML)-markup language and a meta language (language that can be used to define other languages). Used when creating documents to be printed in different formats
-Extensible Markup Language (XML) is used to mark up info that companies share with each other over the internet.
-XHTML: allows tag customization- XML differs from HTML in two ways: (1) XML isn’t a markup language with defined tags. It is a framework in which people can create their own set of tags. (2) XML tags don’t specify how text appears on a web page; the tags covey the meaning (the semantics) of the info included within them.
-HTML includes tags that define the format and style of text in an electronic document and has tags that can create relationships among text within one document or among several documents- hypertext elements.
-HTML Tags-HTML document that is interpreted by web browsers and used to format the display of text enclosed by tags.
-Cascading style sheets (CSS)-instructions-let designers define formatting styles that can be applied to multiple web pages.

Intranets and Extranets
-Intranet: interconnected network that doesn’t extend beyond the organization that created it. -Extranet: an intranet extended to outside entities-ex: suppliers. Participants have access to databases, files, etc.
-Virtual private network (VPN) extranet using public networks and protocols to send sensitive data using IP tunneling or encapsulation - (private passage that provides secure transmission with encrypted packets that are put inside another packet)

Internet Connectivity overview
-Bandwidth amount of data that can travel through a communication line per unit of time.
-Symmetric connections provide the same bandwidth in both directions. Asymmetric connections provide different bandwidths for each direction. Upstream bandwidth (also called upload bandwidth) amount of info that can travel from the user to the internet. Downstream bandwidth -amount of info that can travel from the internet to a user
-Broadband-connections that operate at speeds of greater than about 200 Kbps
-Asymmetric digital subscriber line-provide broadband range & transmission bandwidths
-DSL is a private line with no competing traffic
-Bluetooth one of the first wireless protocols for personal use over short distances
-Ultra Wideband (UWB) provides wide bandwidth connections over short distances developed for short range secure communications
-Wi-Fi (Wireless Ethernet/ 802.11b)- communicate through a wireless access point connected to a LAN to become part of the LAN.
-Wireless access point (WAP) transmits network packets between Wi-Fi computers and other devices within its range.
-Roaming shifting from one WAP to another, without requiring intervention by the user.

Internet2 and the semantic Web
-Internet2: test bed for new network technologies -high bandwidth backbone
-Semantic web-words on web pages being tagged (using XML) with their meanings. People could use intelligent programs called software agents to read the XML tags to determine the meaning of the words in their contexts.

Application
The internet has changed the way in which people communicate. The transition for web 1.0 to web 2.0 allowed us to go from just reading content passively to actually being actively involved in the creating of the content at that very instance. Rather than just sending messages back and forth through email we can now use blogs and communities to instantaneously talk back and forth. This new communicate mode provides more control over information, provides quicker and more efficient communicate and information sharing and collaboration. For businesses on line, web 2.0 can provide more information about customers and easier access to help build relationships. Ex: having a blog on a company website can help customers share information about the products and encourages feedback that can help the company better understand their customers.