Lecture 5Title: Networks and Businesses

By: Mr Hashem AlaidarosMIS 101

Main Points• Components for large networks• IP addresses• VoIP• Intranet vs. Extranet vs. Internet• VPN• Cloud Computing: Models• Web 2 & Web 3

Large Networks• Networks in large companies• Components can include:

• Hundreds of local area networks (LANs) linked to firmwide corporate network

• Various powerful servers• Web site

• Corporate intranet, extranet

• Backend systems

• Mobile wireless LANs (Wi-Fi networks)

• Videoconferencing system

• Telephone network ( handle voice data)

• Wireless cell phones

Corporate Network InfrastructureCorporate Network Infrastructure

Telecommunications and Networking in Today’s Business World

IP addressIP address: is an address that identify each computer that

connected to a network (or Internet)Example of IP address: 52.55.14.7IP address types:

Private (local)Public (global)

IP address and Port number

Cont.• The Future Internet (IPv4 to IPv6)

• The IP addresses currently in use, such as 208.55.112.34 are part of a specification called IPv4.

• However, given the growth rate of the Internet, there aren’t enough IP addresses in this scheme to last beyond 2013.

• IPv6 is a revised addressing convention that will provide over a quadrillion addresses

The Domain Name SystemThe Domain Name System

Figure 7-8The Domain Name System is a hierarchical system with a root domain, top-level domains, second-level domains, and host computers at the third level.

Internet Connection• What is the Internet?

• Connecting to the Internet

• Internet service providers (ISPs)

• Services

• DSL, cable, satellite, T lines (T1, T3)

• T lines (or leased lines) are leased, dedicated lines suitable for businesses or government agencies requiring high-speed guaranteed service levels.

Internet Services• Internet services

• E-mail• Chatting and instant messaging• Newsgroups• File Transfer Protocol (FTP)• World Wide Web• Voice over IP (VoIP)• Virtual private networks (VPNs)

Client/Server Computing on the InternetClient/Server Computing on the Internet

Figure 7-10Client computers running Web browser and other software can access an array of services on servers over the Internet. These services may all run on a single server or on multiple specialized servers.

VoIP• What is VoIP?• An VoIP phone call digitizes and breaks up a voice message into

data packets that may travel along different routes before being reassembled at the final destination.

• A processor nearest the call’s destination, called a gateway, arranges the packets in the proper order and directs them to the telephone number of the receiver or the IP address of the receiving computer.

• Skype, acquired by eBay, offers free VoIP worldwide using a peer-to-peer network.

How Voice over IP WorksHow Voice over IP Works

Figure 7-11

An VoIP phone call digitizes and breaks up a voice message into data packets that may travel along different routes before being reassembled at the final destination. A processor nearest the call’s destination, called a gateway, arranges the packets in the proper order and directs them to the telephone number of the receiver or the IP address of the receiving computer.

The InternetThe Internet

Web Terms• The World Wide Web

• Hypertext Markup Language (HTML): Formats documents for display on Web

• Hypertext Transfer Protocol (HTTP): Communications standard used for transferring Web pages

• Uniform resource locators (URLs): Addresses of Web pages E.g., http://www.megacorp.com/content/features/082602.html

• Web servers: Software for locating and managing Web pages

• Firewall: a device that sits between an internal network and the Internet, limiting access into and out of a network based on access policies

Intranet• Intranets

• They are web pages or resources in a network that is not available to the world outside of the Intranet.

• Used only be insider employees to gain access to corporate information

• The firewall helps to control access between the Intranet and Internet to permit access to the Intranet only to people who are members of the same company or organization. 

• It is accessed is via a username and password

Extranet• Extranets

• An Extranet is actually an Intranet that is partially accessible to authorized outsiders. The actual server (the computer that serves up the web pages) will reside behind a firewall.

• Allow authorized vendors and customers access to an internal intranet

• Example: Used for collaboration between companies and suppliers.

• Example: VPN

• The purpose for both Intranets and Extranets are communication tools for easy information sharing within groups.

IntErnetInternet

It is used when users access a web server (website) that doesn’t reside behind a firewall (if it reside behind a firewall, it would be an Extranet).

All the information is accessible.

Important Question: What are the

benefits and the Problems of

Intranet and Extranet?

How VPN worksA VPN is used to allow access to certain resources

on a network from outside. When you want to connect to a restricted company

resources (files or data) from outside the company:1. you connect to your Internet Service Provider (ISP)2. then activate a VPN client program on your

computer.3. The client program then communicates with a VPN

server at the company and then verifies your username password (by firewall),

4. a secure encrypted link is established and you can access the resources you need.

VPN

Cloud ComputingCloud

Computing is the use of computing resources (hardware and software) that are delivered as a service over the Interne.

Cloud Computing ModelsService as a service (SAAS) allows users to run online applications. Off-

the-shelf applications are accessed over the Internet. The vendors own the applications and the users pay a fixed subscription fees. Great for generic applications, but not for customized, complex applications for large enterprises.

Platform as a service (PAAS) allows users to create their own cloud applications. Basically, provides an environment and set of tools to allow the creation of new web applications. More risk of vendor lock-in because applications cannot be moved easily between platforms.

Infrastructure as a service (IAAS) allows users to run any applications they want to on cloud hardware of their choice. Existing applications can be run on the vendor’s cloud hardware, potentially replacing a company’s data center infrastructure.

Web 2.0• Web 2.0:

• Second-generation interactive Internet-based services enabling people to collaborate, share information, and create new services online

• Blogs: Chronological, informal Web sites created by individuals using easy-to-use weblog publishing tools

• RSS (Really Simple Syndication): Syndicates Web content so aggregator software can pull content for use in another setting or viewing later

• Wikis: Collaborative Web sites where visitors can add, delete, or modify content on the site

Web 3.0• Web 3.0

• Current efforts to make using Web more productive• Inefficiency of current search engines: Of 330 million

search engine queries daily, how many are fruitful?• Semantic Web

• Collaborative effort to add layer of meaning on top of Web, to reduce the amount of human involvement in searching for and processing Web information