Sunday, November 11, 2012

Digital Commerce -some notes for my students

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INTERNET LAW - The Future of E-commerce in Malaysia
IBLS Contributor: Gladys Mirandah, Patrick Mirandah Law Office, Malaysia,
E-commerce has evolved over the years from electronic funds transfers (EFT), comprising of online shopping and Internet banking, to electronic data interchange (EDI), comprising companies' transfer of documents such as purchase orders or invoices. Recent studies foresee a massive growth of e-commerce in the Asian region especially in Malaysia, Singapore, Hong Kong, Korea and Australia; possibly challenging Europe and United States.
Join the Internet Law Forum (ILF) to... discuss, share information and knowledge, questions and doubts... regarding the legal aspects of the Internet. The ILF is ALL about the INTERNET... business, laws and regulations, social media... Sign up to enjoy the benefits of the Free Global membership in the IBLS international community! has evolved over the years from electronic funds transfers (EFT), comprising of online shopping and Internet banking, to electronic data interchange (EDI),  comprising companies' transfer of documents such as purchase orders or invoices. Recent studies foresee a massive growth of e-commerce in the Asian region especially in Malaysia, Singapore, Hong Kong, Korea and Australia; possibly challenging Europe and United States.  
E-commerce has its numerous advantages.  For instance, it overcomes geographical limitations to allow market expansion; decreases administrative, marketing and logistics costs; increases efficiency and provides a competitive environment to improve quality of service. However, there are some concerns that need to be addressed, particularly, privacy issues, legal issues such as copyright infringement, protection of patent rights, domain name disputes and preservation of trade secrets as well as issues pertaining to the validity and enforcement of agreements made online.
Governments and regulatory bodies throughout Asia have recognized the prospects of e-commerce and policies have been designed to amend the existing laws to deal with the emerging legal issues post by e-commerce transactions. To attract new online business opportunities and increase the competency of e-commerce in the Asian region, it is important for international businessmen and their legal advisors to be familiar with the e-commerce laws, policies and regulations throughout Asia.
To date, some of the legislations that have been conceded in Asia include: Australia"s Electronic Transactions Act 1999; Broadcasting Services Amendment (On-Line Services) Act 1999; Privacy (Private Sector) Bill and the Copyright Amendment (Digital Agenda) Bill 1999; South Korea's Electronic Transaction Basic Act; Singapore's Electronic Transaction Act 1998; Hong Kong Electronic Transactions Ordinance 2000; Japan's Draft Bill Concerning Electronic Signatures and Certification Authorities and the Law Partially Amending the Trade Mark Law; the Philippines' Electronic Commerce Act; and India's Information Technology Act 2000.
Malaysia was one of the pioneers amongst Asian countries to establish a new federal ministry, Ministry of Energy, Communications and Multimedia. The main function of this Ministry is to spearhead and promote the growth of information and communication technology (ICT) with the support of several agencies, including the Malaysian Institute of Microelectronic Systems (MIMOS) established in 1984, Multimedia Development Corporation (MDC) established in 1996, and Malaysian Communications and Multimedia Commission (or MCMC) established in 1998.
These agencies contribute to e-commerce by developing their own agenda.  For instance, the Multimedia Development Corporation has been working on a National Electronic Commerce Masterplan designed to facilitate the growth of e-commerce in Malaysia. The four key elements in this Masterplan are to boost confidence in on-line trading, prepare a regulatory framework, build a critical mass of Internet users and introduce an electronic payment system.
Amongst the legislations that have been passed in Malaysia are Malaysian Communications and Multimedia Commission Act 1998; Communications and Multimedia Act 1998; Digital Signature Act 1997; Computer Crimes Act 1997; and Telemedicine Act 1997. These legislations have been amended over the years in attempts to better address emerging e-commerce issues.
In lieu with the importance of e-commerce, the Malaysian Government has allocated RM 12.9 billion for the Ninth Malaysia Plan (2006-2010). On a broader perspective, Malaysia is participating in Asia Pacific Economic Cooperation's (APEC) to contribute in the efforts of introducing e-commerce laws, policies and regulations to facilitate e-commerce transactions internationally.
The future of e-commerce in Malaysia and the Asia region is bright. Governments and regulatory bodies are collaborating on a wider platform to ensure e-commerce law, policy and regulations are enforced to provide a guideline for traders to systematically utilize e-commerce and in tandem ensure protection for e-commerce users.
IBLS Contributor: Gladys Mirandah, Patrick Mirandah Law Office, Malaysia,
Malaysia ranked 3rd in most shoppers shopped online in Asia  (2011/1/6)
According to Visa eCommerce Consumer Monitor, a survey conducted by The Nielsen Company in an effort to measure online spending behavior of shoppers in six Asian economies (Mainland China, India, Indonesia, Malaysia, Taiwan and Thailand), Taiwan topped on the list, followed by Mainland China and Malaysia is the 3rd among the countries....more...

Posted by netbuilder on 2011/1/6 11:15:05
According to Visa eCommerce Consumer Monitor, a survey conducted by The Nielsen Company in an effort to measure online spending behavior of shoppers in six Asian economies (Mainland China, India, Indonesia, Malaysia, Taiwan and Thailand), Taiwan topped on the list, followed by Mainland China and Malaysia is the 3rd among the countries.
Based on the findings, Malaysians spent on average over RM6,000 shopping online. Most of the online shoppers feel more convenient to shop online than go to an actual store.
Visa Survey Finds Nine in Ten Have Shopped Online Over the Past Year
Singapore, 04 January 2011

How to convert your business into E-commerce?

Digital Commerce

Table of Contents
Aim: To create a 'c-book' on what it means to be a digital citizen in the 21st century.

1. Overview/Description

Digital Commerce is defined as the electronic selling and buying of goods however it goes further than that, nowadays technology is having a tremendous influence in our lives; currently we are having to deal with the fact that a large share of market economy is being done electronically. The Internet now gives us the opportunity to purchase a wide variety of products, as toys, clothes, cars, food, etc yet this faces a problem as illegal goods are being sold as well and this makes Digital Commerce something to think about. The access to almost any products makes us wonder about the legal and illegal acts that could be done simply by trading on the net. The point of this explanation is to make others aware, specially young students that the electronic commerce might be dangerous thus at the same time might be useful, it is important to know how to commerce electronically correctly. The rise of the digital economy does not change the issue of right and wrong, but it does enhance the user’s access to buying and selling goods, which magnifies the issue of illegal activities.
We may summarize what Digital Commerce is in 4 points:

  • Online buying
  • Online selling
  • Media subscriptions (i.e., i tunes)
  • Buying and selling "virtual merchandise" for online games

Why are more people shopping online?
This video shows one of the many benefits that we get if we shop online, we wont have to go through what this lady does.

Digital Commerce is the electronic buying and selling of goods. Now a days, a large amount is being purchased on the internet, because it’s easier and more convenient. Almost anything can be bought such as music, toys clothing, cars, food and even porn. Even though some of these purchases are illegal we will be focusing on all the item’s you can buy legally on the internet. Some of the popular websites are
eBay, iTunes, Amazon, HMV, Best Buy and much more.

2. Background

-Commerce drives virtual world:
This article talks about how Michelle Valentine visits an online auction site which helps thousands of members to move all manner of virtual goods that they have created. These auctions are creative and very useful.
This is an example of Digital Commerce because it shows how people trade and commerce online with other people, this improves our capacities as buyers as well as sellers. There is a vast marketplace of goods being created and this is why the economy is humming.Players buy and sell things in several ways. Members run stores, they have their own catalog and people sell to each other one-on-one. But perhaps the most popular, and most efficient, is the auction system, which is much like eBay.
This proves how the internet can be used responsibly and safely, and is positively affecting the economy as each day more and more people and joining this program.

**New ways to untether travelers** :
This article talks about how technology seldom arrives on the counter wrapped in pretty foil and ready to go like a box of fancy chocolates.
It explains how technology advances more each day, as we are in a new era, everything around us is improving thanks to technology. It all started with new cellphones and now it is evolving with the use of internet on airplanes, hotels and public areas. All this is happening thanks to
Wi-Fi which is a system that uses radio frequencies to build local zones where laptops or personal digital devices can have access to Internet.
Thus even though the Internet might face some challenges, those can be easily solved in seconds which demonstrates that things are going much faster and that technology is becoming more useful for us. This is another great example of Digital Commerce.

**Porn law targets cybersquatters**:
This last article explains how prosecutors are looking to build a forceful test case against predatory domain-name practices. It about how people who unwittingly enter the misspelled names into their browser windows find themselves confronted with porn, pop-up ads and other unwanted distractions. To make matters worse, prosecutors note, some of those domains appear to directly target children. Current picks include the websites and, variations on the animated programs
Teletubbies and Bob the Builder. But rather than finding their cartoon friends, those who type in the misspelled Web addresses get directed to a garish porn site called Hanky Panky College.
The policy experts say that downloading pornographic content on the internet and linking it to children is clearly a criminal offense and those who practice it should be punished. This is another example of Digital Commerce as those who are searching for some events and find others they do not wish to see, might feel uncomfortable. Overall it proves that even though the internet is very useful it might also be dangerous.

3. Social/ ethical aspects

  • Privacy and anonymity: This social aspect is very important in Digital Commerce. It refers to how we must be aware that privacy online is required, anonymity is involved as to who should be allowed to be anonymous in network interactions and under what circumstances. It also refers to consumer privacy, specially when buying online. Thus privacy is required because the implicit dangers are enormous and can easily affect anyone of us.
  • Security: This social aspect is very essential, security is necessary when it refers to buying items online, it is required because we must ensure that our private information doesn't go everywhere and that the pages we are visiting are safe.
  • Policies and standards:

What others can you add?

4. Possible solutions to the problems

There are always questions that pop up when someone is shopping online. Am I protected online? Is my credit card number safe? How can I keep my credit card number safe? There are many different tools and tricks you should know to buy and sell correctly online.

Am I protected online?
If you take the right approach towards online shopping, you won't have to worry about hackers and you will be 100% safe. One of the most dangerous threats to your personal information is a scam. A scam is when someone tricks you into giving them your personal information online. As long as you do not give out personal information, you will be safe.

‍How can I keep my credit card number safe?
There are many ways to keep your credit card number safe online. One way you can tell that the website you are shopping on is safe is if it has https: at the front of the URL. The "s" in https: stands for secure. If it only has http:, it is not guarenteed to be a safe website. When you use Internet Explorer, there is usuall a padlock at the bottom to assure the safety of the page.

‍What do I do if my identity is stolen?
The first thing you should do if your identity is stolen is to contact your credit card company and cancel your credit card to prevent anything being bought under your name. Then you should contact the authorities so they can find out who stole your credit card and be prosecuted.

5. Guidelines for teenagers

There are many ways to prevent teenagers from getting into the digital commerce world. Parents could stop teens by watching what kids do frequently. Most sites will not let teens buy or sell things over the internet unless they are 18. When teens turn 18, most parents really can't stop them anyways because they are legal to do some things. There are sites that let you buy stuff like music, movies, and other items. Sites such as iTunes, Ebay, and Amazon are part of Digital Commerce. Most of these web sites require credit cards. Unless that teen is independent, you can just not give your kid your credit card. Most commerce websites are legal such as iTunes. There are some sites that you should stay away such as Limewire and Frostwire. These sites let you download music for free but it is illegal and could give yourcomputer a virus. One way to restrict that is to block those sites. Parents should always check their kids computers to see what is downloaded onto their computer such as Limewire. If you find program like that then you should delete it immediately because it is against the law.

Input/Ideas for Digiteen Contract:

Think about it:
How children and teens can be safe during digital commerce:

"One of the most amazing things of Internet culture is that children are the most computer literate among us, but their vulnerability to on-line predators prevents their being able to enjoy or explore freely what is likely to be the defining medium of their lives.
The problem, to date, is intractable. On one hand, how do on-line services create a safe place for children to meet and play together while at the same time protecting them from pedophiles and unscrupulous marketers who often pose as children? On the other, how can we keep children away from pornographic adult sites, which are accessible at the click of a mouse button?
For example, America Online's ''Kids Only'' site displays many warnings and safety tips, but its ''pager'' system, which allows children to summon a monitor if they feel threatened on line, is hopelessly backed up. Many users report waiting half an hour or longer for a monitor to respond.
The result was Safe Playgrounds, which Mr. Morgan is now asking industry executives and politicians to support. Its tenets are:
To develop a ''kid's browser'' that includes an unbreakable bit of software code that Mr. Morgan is calling a G-bit, for general audience. This identifies the user as someone who is either under 18 years old or who does not want to see adult material. Web publishers then rate and code their own sites, and anyone who shows up at an adult site with this G-bit will be denied access."

Digital commerce can also be risky, because people sometimes get nervous about putting their credit card details on the internet or theft. There are a lot of different ways for paying for your online purchases, such as debit cards, electronic money, cash on delivery, cheques, wire transfer, postal money orders. Paypal, moneybookers, reverse sms billing so that the bill is sent with your phone bill, gift cards and of course credit cards.

Because buyers cannot see the real product before they purchase it, there are more chances of fraud happening. SSL (the secure socket layer) has solved the problem of credit card details being stolen but identity thefts are still an issue when they hack into the supplier's site and steal names, credit card numbers, addresses and other personal information.

To avoid theft, only shop from sites that you know and have heard are good and reliable, read the privacy policy to make sure you do agree with it, make sure that the vendor address is protected with SSL, and you will know this because the url begins with "https" instead of just "http", and to make sure your passwords are strong (a mixture of letters and numbers) and you don't display any unnecessary personal information.
It seems so much more convenient to do your shopping when you are sitting at your computer, not having to get up and go to the shops, and most of the sites deliver to your house. It is also convenient because they are open all day, everyday. This is why in 2006 alone, the US made $146.4 billion in online shopping or online auctions.

Ebay is a great example of an online auction. On Ebay you can sell or buy collectibles, appliances, computers, furniture, equipment, vehicles and other types of items. Nearly anything can be sold on Ebay, as long as it isn't illegal and does not violate the Ebay Prohibited and Restricted Items Policy. You can buy new items or second items on Ebay. Companies often sell new releases on Ebay as well as in the shops to maximize sales.

A few tips when buying or selling on the internet:

  • Know how the scams work. They only work if they can fool you. If you know about them they can't fool you. Read about the most common ones that affect this website by clicking here.
  • Purchase in person if possible. The most expensive items sold in the classifieds on this site are motorcycles. If you see a good deal on a motorcycle that is thousands of miles from you, there is a good chance you'll find a similar deal close to you. If the deal really good you might find it worth wile to travel.
  • Use a secure method of sending money. Never send cash or transfer money via Western Union to an unknown person. OK, it looks like were picking on Western Union. We don't mean to. They are great for sending money to someone you know.
  • Use a third party to help with the transaction. Escrow companies can help but be very cautious. Make sure you are dealing with a real and licensed escrow company. Many scammers are setting up fake companies to collect the money. This can be a problem if you are selling also. This is one of the common scams. Please take the time to read about it by clicking here. Some fake companies can be very convincing. If in doubt, don't use them. We have a few tips for spotting fraudulent escrow companies. Click here for that information.

Statistics from Vienna International School
45 students from Grade 8 (13-14 year olds) took this survey.
Have you ever purchased anything online?(books, songs, clothes etc.)
Yes 37/45 82% No 8/45 18%
Have you ever looked at an item online before buying it somewhere else?
Yes 36/45 80% No 9/45 20%
Do you feel safe giving out credit card details online?
Yes 12/45 27% no 29/45 64% (4 people weren't sure)
Do you think you will buy things online in the future?
Yes 39/45 87% No 6/45 13%

Bottom of Form

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Electronic commerce

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Electronic commerce, commonly known as e-commerce or e-comm, is the buying and selling of products or services over electronic systems such as the Internet and other computer networks. Electronic commerce draws on such technologies as electronic funds transfer, supply chain management, Internet marketing, online transaction processing, electronic data interchange (EDI), inventory management systems, and automated data collection systems. Modern electronic commerce typically uses the World Wide Web at least at one point in the transaction's life-cycle, although it may encompass a wider range of technologies such as e-mail, mobile devices and telephones as well.
  • Electronic commerce is generally considered to be the sales aspect of e-business. It also consists of the exchange of data to facilitate the financing and payment aspects of business transactions.
E-commerce can be divided into:
  • E-tailing or "virtual storefronts" on Web sites with online catalogs, sometimes gathered into a "virtual mall"
  • The gathering and use of demographic data through Web contacts
  • Electronic Data Interchange (EDI), the business-to-business exchange of data
  • E-mail and fax and their use as media for reaching prospects and established customers (for example, with newsletters)
  • Business-to-business buying and selling
  • The security of business transactions



[edit] History

[edit] Early development

Originally, electronic commerce was identified as the facilitation of commercial transactions electronically, using technology such as Electronic Data Interchange (EDI) and Electronic Funds Transfer (EFT). These were both introduced in the late 1970s, allowing businesses to send commercial documents like purchase orders or invoices electronically. The growth and acceptance of credit cards, automated teller machines (ATM) and telephone banking in the 1980s were also forms of electronic commerce. Another form of e-commerce was the airline reservation system typified by Sabre in the USA and Travicom in the UK.
Beginning in the 1990s, electronic commerce would include enterprise resource planning systems (ERP), data mining and data warehousing
In 1990, Tim Berners-Lee invented the WorldWideWeb web browser and transformed an academic telecommunication network into a worldwide everyman everyday communication system called internet/www. Commercial enterprise on the Internet was strictly prohibited by NSF until 1995.[1] Although the Internet became popular worldwide around 1994 with the adoption of Mosaic web browser, it took about five years to introduce security protocols (i.e. SSL encryption enabled on Netscape 1.0 Browser in late 1994) and DSL allowing continual connection to the Internet. By the end of 2000, many European and American business companies offered their services through the World Wide Web. Since then people began to associate a word "ecommerce" with the ability of purchasing various goods through the Internet using secure protocols and electronic payment services.

[edit] Timeline

The timeline for e-commerce progression is shown below.
  • 1979: Michael Aldrich invented online shopping[2]
  • 1981: Thomson Holidays, UK is first B2B online shopping[citation needed]
  • 1982: Minitel was introduced nationwide in France by France Telecom and used for online ordering.
  • 1984: Gateshead SIS/Tesco is first B2C online shopping and Mrs Snowball, 72, is the first online home shopper[3]
  • 1984: In April 1984, CompuServe launches the Electronic Mall in the USA and Canada. It is the first comprehensive electronic commerce service.[4]
  • 1985: Nissan UK sells cars and finance with credit checking to customers online from dealers' lots.[citation needed]
  • 1987: Swreg begins to provide software and shareware authors means to sell their products online through an electronic Merchant account.[citation needed]
  • 1992: Tim Berners-Lee writes the first web browser, WorldWideWeb, using a NeXT computer.
  • 1992: Terry Brownell launches first fully graphical, iconic navigated Bulletin board system online shopping using RoboBOARD/FX.
  • 1994: Netscape releases the Navigator browser in October under the code name Mozilla. Pizza Hut offers online ordering on its Web page. The first online bank opens. Attempts to offer flower delivery and magazine subscriptions online. Adult materials also become commercially available, as do cars and bikes. Netscape 1.0 is introduced in late 1994 SSL encryption that made transactions secure.
  • 1995: Thursday 27 April 1995, the purchase of a book by Paul Stanfield, Product Manager for CompuServe UK, from W H Smith’s shop within CompuServe’s UK Shopping Centre is the UK’s first national online shopping service secure transaction. The shopping service at launch featured WH Smith, Tesco, Virgin/Our Price, Great Universal Stores/GUS, Interflora, Dixons Retail, Past Times, PC World (retailer) and Innovations.[5]
  • 1995: Jeff Bezos launches and the first commercial-free 24 hour, internet-only radio stations, Radio HK and NetRadio start broadcasting. Dell and Cisco begin to aggressively use Internet for commercial transactions. eBay is founded by computer programmer Pierre Omidyar as AuctionWeb.
  • 1998: Electronic postal stamps can be purchased and downloaded for printing from the Web.
  • 1998: Alibaba Group is established in China.
  • 1999: sold for US $7.5 million to eCompanies, which was purchased in 1997 for US $149,000. The peer-to-peer filesharing software Napster launches. ATG Stores launches to sell decorative items for the home online.
  • 2000: The dot-com bust.
  • 2001: achieved profitability in December 2001.
  • 2002: eBay acquires PayPal for $1.5 billion.[6] Niche retail companies Wayfair and NetShops are founded with the concept of selling products through several targeted domains, rather than a central portal.
  • 2003: posts first yearly profit.
  • 2004:, China's first online b2b transaction platform, is established, forcing other b2b sites to move away from the "yellow pages" model.[7]
  • 2005: Yuval Tal founds Payoneer - a secure online payment distribution solution
  • 2007: acquired by R.H. Donnelley for $345 million.[8]
  • 2009: acquired by for $928 million.[9] Retail Convergence, operator of private sale website, acquired by GSI Commerce for $180 million, plus up to $170 million in earn-out payments based on performance through 2012.[10]
  • 2010: Groupon reportedly rejects a $6 billion offer from Google. Instead, the group buying websites plans to go ahead with an IPO in mid-2011.[11]
  • 2011:, parent company of, acquired by for $500 million in cash plus $45 million in debt and other obligations.[12] GSI Commerce, a company specializing in creating, developing and running online shopping sites for brick and mortar businesses, acquired by eBay for $2.4 billion.[13]
  • 2012: US eCommerce and Online Retail sales projected to reach $226 billion, an increase of 12 percent over 2011.[14]
An example of an automated online assistant on a merchandising website.
Some common applications related to electronic commerce are the following:


Contemporary electronic commerce involves everything from ordering "digital" content for immediate online consumption, to ordering conventional goods and services, to "meta" services to facilitate other types of electronic commerce.
On the institutional level, big corporations and financial institutions use the internet to exchange financial data to facilitate domestic and international business. Data integrity and security are very hot and pressing issues for electronic commerce.

[edit] Global trends

Business models across the world also continue to change drastically with the advent of e-commerce and this change is not just restricted to USA. Other countries are also contributing to the growth of e-commerce. For example, the United Kingdom has the biggest e-commerce market in the world when measured by the amount spent per capita, even higher than the USA. The internet economy in UK is likely to grow by 10% between 2010 to 2015. This has led to changing dynamics for the advertising industry[23]
Amongst emerging economies, China's e-commerce presence continues to expand. With 384 million internet users, China's online shopping sales rose to $36.6 billion in 2009 and one of the reasons behind the huge growth has been the improved trust level for shoppers. The Chinese retailers have been able to help consumers feel more comfortable shopping online.[24] eCommerce is also expanding across the Middle East. Having recorded the world’s fastest growth in internet usage between 2000 and 2009, the region is now home to more than 60 million internet users. Retail, travel and gaming are the region’s top eCommerce segments, in spite of difficulties such as the lack of region-wide legal frameworks and logistical problems in cross-border transportation.[25] E-Commerce has become an important tool for businesses worldwide not only to sell to customers but also to engage them.[26]

[edit] Impact on markets and retailers

Economists have theorized that e-commerce ought to lead to intensified price competition, as it increases consumers' ability to gather information about products and prices. Research by four economists at the University of Chicago has found that the growth of online shopping has also affected industry structure in two areas that have seen significant growth in e-commerce, bookshops and travel agencies. Generally, larger firms have grown at the expense of smaller ones, as they are able to use economies of scale and offer lower prices. The lone exception to this pattern has been the very smallest category of bookseller, shops with between one and four employees, which appear to have withstood the trend.[27]

[edit] Distribution channels

E-commerce has grown in importance as companies have adopted Pure-Click and Brick and Click channel systems. We can distinguish between pure-click and brick and click channel system adopted by companies.
  • Pure-Click companies are those that have launched a website without any previous existence as a firm. It is imperative that such companies must set up and operate their e-commerce websites very carefully. Customer service is of paramount importance.
  • Brick and Click companies are those existing companies that have added an online site for e-commerce. Initially, Brick and Click companies were skeptical whether or not to add an online e-commerce channel for fear that selling their products might produce channel conflict with their off-line retailers, agents, or their own stores. However, they eventually added internet to their distribution channel portfolio after seeing how much business their online competitors were generating.

See also

A computer network, often simply referred to as a network, is a collection of computers and other hardware components interconnected by communication channels that allow sharing of resources and information.[1] Where at least one process in one device is able to send/receive data to/from at least one process residing in a remote device, then the two devices are said to be in a network. Simply, more than one computer interconnected through a communication medium for information interchange is called a computer network.

Networks may be classified according to a wide variety of characteristics, such as the medium used to transport the data, communications protocol used, scale, topology, and organizational scope.
Communications protocols define the rules and data formats for exchanging information in a computer network, and provide the basis for network programming. Well-known communications protocols include Ethernet, a hardware and link layer standard that is ubiquitous in local area networks, and the Internet protocol suite, which defines a set of protocols for internetworking, i.e. for data communication between multiple networks, as well as host-to-host data transfer, and application-specific data transmission formats.
Computer networking is sometimes considered a sub-discipline of electrical engineering, telecommunications, computer science, information technology or computer engineering, since it relies upon the theoretical and practical application of these disciplines.



[edit] History
Distributed processing
This section requires expansion. (December 2010)
Before the advent of computer networks that were based upon some type of telecommunications system, communication between calculation machines and early computers was performed by human users by carrying instructions between them. Many of the social behaviors seen in today's Internet were demonstrably present in the 19th century and arguably in even earlier networks using visual signals.
Today, computer networks are the core of modern communication. All modern aspects of the public switched telephone network (PSTN) are computer-controlled, and telephony increasingly runs over the Internet Protocol, although not necessarily the public Internet. The scope of communication has increased significantly in the past decade, and this boom in communications would not have been possible without the progressively advancing computer network. Computer networks, and the technologies needed to connect and communicate through and between them, continue to drive computer hardware, software, and peripherals industries. This expansion is mirrored by growth in the numbers and types of users of networks, from the researcher to the home user.

[edit] Properties

Computer networks:
Facilitate communications 
Using a network, people can communicate efficiently and easily via email, instant messaging, chat rooms, telephone, video telephone calls, and video conferencing.
Permit sharing of files, data, and other types of information
In a network environment, authorized users may access data and information stored on other computers on the network. The capability of providing access to data and information on shared storage devices is an important feature of many networks.
Share network and computing resources
In a networked environment,defined by sonu barnwal CENTRAL UNIVERSITY OF BIHAR each computer on a network may access and use resources provided by devices on the network, such as printing a document on a shared network printer. Distributed computing uses computing resources across a network to accomplish tasks.
May be insecure
A computer network may be used by computer hackers to deploy computer viruses or computer worms on devices connected to the network, or to prevent these devices from normally accessing the network (denial of service).
May interfere with other technologies
Power line communication strongly disturbs certain forms of radio communication, e.g., amateur radio.[5] It may also interfere with last mile access technologies such as ADSL and VDSL.[6]
May be difficult to set up
A complex computer network may be difficult to set up. It may also be very costly to set up an effective computer network in a large organization or company.

[edit] Communication media

Computer networks can be classified according to the hardware and associated software technology that is used to interconnect the individual devices in the network, such as electrical cable (HomePNA, power line communication,, optical fiber, and radio waves (wireless LAN). In the OSI model, these are located at levels 1 and 2.
A well-known family of communication media is collectively known as Ethernet. It is defined by IEEE 802 and utilizes various standards and media that enable communication between devices. Wireless LAN technology is designed to connect devices without wiring. These devices use radio waves or infrared signals as a transmission medium.

[edit] Wired technologies

The order of the following wired technologies is, roughly, from slowest to fastest transmission speed.
  • Twisted pair wire is the most widely used medium for telecommunication. Twisted-pair cabling consist of copper wires that are twisted into pairs. Ordinary telephone wires consist of two insulated copper wires twisted into pairs. Computer networking cabling (wired Ethernet as defined by IEEE 802.3) consists of 4 pairs of copper cabling that can be utilized for both voice and data transmission. The use of two wires twisted together helps to reduce crosstalk and electromagnetic induction. The transmission speed ranges from 2 million bits per second to 10 billion bits per second. Twisted pair cabling comes in two forms: unshielded twisted pair (UTP) and shielded twisted-pair (STP). Each form comes in several category ratings, designed for use in various scenarios.
  • Coaxial cable is widely used for cable television systems, office buildings, and other work-sites for local area networks. The cables consist of copper or aluminum wire surrounded by an insulating layer (typically a flexible material with a high dielectric constant), which itself is surrounded by a conductive layer. The insulation helps minimize interference and distortion. Transmission speed ranges from 200 million bits per second to more than 500 million bits per second.
  • An optical fiber is a glass fiber. It uses pulses of light to transmit data. Some advantages of optical fibers over metal wires are less transmission loss, immunity from electromagnetic radiation, and very fast transmission speed, up to trillions of bits per second. One can use different colors of lights to increase the number of messages being sent over a fiber optic cable.

[edit] Wireless technologies

  • Terrestrial microwave – Terrestrial microwave communication uses Earth-based transmitters and receivers resembling satellite dishes. Terrestrial microwaves are in the low-gigahertz range, which limits all communications to line-of-sight. Relay stations are spaced approximately 48 km (30 mi) apart.
  • Communications satellites – The satellites communicate via microwave radio waves, which are not deflected by the Earth's atmosphere. The satellites are stationed in space, typically in geosynchronous orbit 35,400 km (22,000 mi) above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.
  • Cellular and PCS systems use several radio communications technologies. The systems divide the region covered into multiple geographic areas. Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
  • Radio and spread spectrum technologies – Wireless local area network use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area. IEEE 802.11 defines a common flavor of open-standards wireless radio-wave technology.
  • A global area network (GAN) is a network used for supporting mobile across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is handing off user communications from one local coverage area to the next. In IEEE Project 802, this involves a succession of terrestrial wireless LANs.[7]

[edit] Exotic technologies

There have been various attempts at transporting data over more or less exotic media:
  • Extending the Internet to interplanetary dimensions via radio waves.[9]
Both cases have a large round-trip delay time, which prevents useful communication.

[edit] Communications protocols and network programming
Internet map. The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP) to serve billions of users worldwide.
A communications protocol is a set of rules for exchanging information over a network. It is typically a protocol stack (also see the OSI model), which is a "stack" of protocols, in which each protocol uses the protocol below it. An important example of a protocol stack is HTTP running over TCP over IP over IEEE 802.11 (TCP and IP are members of the Internet Protocol Suite, and IEEE 802.11 is a member of the Ethernet protocol suite). This stack is used between the wireless router and the home user's personal computer when the user is surfing the web.
Communication protocols have various properties, such as whether they are connection-oriented or connectionless, whether they use circuit mode or packet switching, or whether they use hierarchical or flat addressing.
There are many communication protocols, a few of which are described below.

[edit] Ethernet

Main article: Ethernet
Ethernet is a family of connectionless protocols used in LANs, described by a set of standards together called IEEE 802 published by the Institute of Electrical and Electronics Engineers. It has a flat addressing scheme and is mostly situated at levels 1 and 2 of the OSI model. For home users today, the most well-known member of this protocol family is IEEE 802.11, otherwise known as Wireless LAN (WLAN). However, the complete protocol suite deals with a multitude of networking aspects not only for home use, but especially when the technology is deployed to support a diverse range of business needs. MAC bridging (IEEE 802.1D) deals with the routing of Ethernet packets using a Spanning Tree Protocol, IEEE 802.1Q describes VLANs, and IEEE 802.1X defines a port-based Network Access Control protocol, which forms the basis for the authentication mechanisms used in VLANs, but it is also found in WLANs – it is what the home user sees when the user has to enter a "wireless access key".

[edit] Internet Protocol Suite

The Internet Protocol Suite, often also called TCP/IP, is the foundation of all modern internetworking. It offers connection-less as well as connection-oriented services over an inherently unreliable network traversed by datagram transmission at the Internet protocol (IP) level. At its core, the protocol suite defines the addressing, identification, and routing specification in form of the traditional Internet Protocol Version 4 (IPv4) and IPv6, the next generation of the protocol with a much enlarged addressing capability.

[edit] SONET/SDH

Synchronous Optical Networking (SONET) and Synchronous Digital Hierarchy (SDH) are standardized multiplexing protocols that transfer multiple digital bit streams over optical fiber using lasers. They were originally designed to transport circuit mode communications from a variety of different sources, primarily to support real-time, uncompressed, circuit-switched voice encoded in PCM(Pulse-Code Modulation) format. However, due to its protocol neutrality and transport-oriented features, SONET/SDH also was the obvious choice for transporting Asynchronous Transfer Mode (ATM) frames.

[edit] Asynchronous Transfer Mode

Asynchronous Transfer Mode (ATM) is a switching technique for telecommunication networks. It uses asynchronous time-division multiplexing and encodes data into small, fixed-sized cells. This differs from other protocols such as the Internet Protocol Suite or Ethernet that use variable sized packets or frames. ATM has similarity with both circuit and packet switched networking. This makes it a good choice for a network that must handle both traditional high-throughput data traffic, and real-time, low-latency content such as voice and video. ATM uses a connection-oriented model in which a virtual circuit must be established between two endpoints before the actual data exchange begins.
While the role of ATM is diminishing in favor of next-generation networks, it still plays a role in the last mile, which is the connection between an Internet service provider and the home user. For an interesting write-up of the technologies involved, including the deep stacking of communications protocols used, see.[10]

[edit] Network programming

Main article: Network socket
Computer network programming involves writing computer programs that communicate with each other across a computer network. Different programs must be written for the client process, which initiates the communication, and for the server process, which waits for the communication to be initiated. Both endpoints of the communication flow are implemented as network sockets; hence network programming is basically socket programming.

[edit] Scale

Computer network types by geographical scope
Networks are often classified by their physical or organizational extent or their purpose. Usage, trust level, and access rights differ between these types of networks.

[edit] Personal area network

A personal area network (PAN) is a computer network used for communication among computer and different information technological devices close to one person. Some examples of devices that are used in a PAN are personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. A PAN may include wired and wireless devices. The reach of a PAN typically extends to 10 meters.[11] A wired PAN is usually constructed with USB and Firewire connections while technologies such as Bluetooth and infrared communication typically form a wireless PAN.

[edit] Local area network

A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as home, school, computer laboratory, office building, or closely positioned group of buildings. Each computer or device on the network is a node. Current wired LANs are most likely to be based on Ethernet technology, although new standards like ITU-T also provide a way to create a wired LAN using existing home wires (coaxial cables, phone lines and power lines).[12]
Typical library network, in a branching tree topology and controlled access to resources
A sample LAN is depicted in the accompanying diagram. All interconnected devices must understand the network layer (layer 3), because they are handling multiple subnets (the different colors). Those inside the library, which have only 10/100 Mbit/s Ethernet connections to the user device and a Gigabit Ethernet connection to the central router, could be called "layer 3 switches" because they only have Ethernet interfaces and must understand IP. It would be more correct to call them access routers, where the router at the top is a distribution router that connects to the Internet and academic networks' customer access routers.
The defining characteristics of LANs, in contrast to WANs (Wide Area Networks), include their higher data transfer rates, smaller geographic range, and no need for leased telecommunication lines. Current Ethernet or other IEEE 802.3 LAN technologies operate at data transfer rates up to 10 Gbit/s. IEEE has projects investigating the standardization of 40 and 100 Gbit/s.[13] LANs can be connected to Wide area network by using routers.

[edit] Home area network

A home area network (HAN) is a residential LAN which is used for communication between digital devices typically deployed in the home, usually a small number of personal computers and accessories, such as printers and mobile computing devices. An important function is the sharing of Internet access, often a broadband service through a cable TV or Digital Subscriber Line (DSL) provider.

[edit] Storage area network

A storage area network (SAN) is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to make storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear like locally attached devices to the operating system. A SAN typically has its own network of storage devices that are generally not accessible through the local area network by other devices. The cost and complexity of SANs dropped in the early 2000s to levels allowing wider adoption across both enterprise and small to medium sized business environments.

[edit] Campus area network

A campus area network (CAN) is a computer network made up of an interconnection of LANs within a limited geographical area. The networking equipment (switches, routers) and transmission media (optical fiber, copper plant, Cat5 cabling etc.) are almost entirely owned (by the campus tenant / owner: an enterprise, university, government etc.).
In the case of a university campus-based campus network, the network is likely to link a variety of campus buildings including, for example, academic colleges or departments, the university library, and student residence halls.

[edit] Backbone network

A backbone network is part of a computer network infrastructure that interconnects various pieces of network, providing a path for the exchange of information between different LANs or subnetworks. A backbone can tie together diverse networks in the same building, in different buildings in a campus environment, or over wide areas. Normally, the backbone's capacity is greater than that of the networks connected to it.
A large corporation which has many locations may have a backbone network that ties all of these locations together, for example, if a server cluster needs to be accessed by different departments of a company which are located at different geographical locations. The equipment which ties these departments together constitute the network backbone. Network performance management including network congestion are critical parameters taken into account when designing a network backbone.
A specific case of a backbone network is the Internet backbone, which is the set of wide-area network connections and core routers that interconnect all networks connected to the Internet.

[edit] Metropolitan area network

A Metropolitan area network (MAN) is a large computer network that usually spans a city or a large campus.
Sample EPN made of Frame relay WAN connections and dialup remote access.
Sample VPN used to interconnect 3 offices and remote users

[edit] Wide area network

A wide area network (WAN) is a computer network that covers a large geographic area such as a city, country, or spans even intercontinental distances, using a communications channel that combines many types of media such as telephone lines, cables, and air waves. A WAN often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.

[edit] Enterprise private network

An enterprise private network is a network built by an enterprise to interconnect various company sites, e.g., production sites, head offices, remote offices, shops, in order to share computer resources.

[edit] Virtual private network

A virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires. The data link layer protocols of the virtual network are said to be tunneled through the larger network when this is the case. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.
VPN may have best-effort performance, or may have a defined service level agreement (SLA) between the VPN customer and the VPN service provider. Generally, a VPN has a topology more complex than point-to-point.

[edit] Virtual Network

Not to be confused with a Virtual Private Network, a Virtual Network defines data traffic flows between virtual machines within a hypervisor in a virtual computing environment. Virtual Networks may employ virtual security switches, virtual routers, virtual firewalls and other virtual networking devices to direct and secure data traffic.

[edit] Internetwork

An internetwork is the connection of multiple computer networks via a common routing technology using routers. The Internet is an aggregation of many connected internetworks spanning the Earth.

[edit] Organizational scope

Networks are typically managed by organizations which own them. According to the owner's point of view, networks are seen as intranets or extranets. A special case of network is the Internet, which has no single owner but a distinct status when seen by an organizational entity – that of permitting virtually unlimited global connectivity for a great multitude of purposes.

[edit] Intranets and extranets

Intranets and extranets are parts or extensions of a computer network, usually a LAN.
An intranet is a set of networks, using the Internet Protocol and IP-based tools such as web browsers and file transfer applications, that is under the control of a single administrative entity. That administrative entity closes the intranet to all but specific, authorized users. Most commonly, an intranet is the internal network of an organization. A large intranet will typically have at least one web server to provide users with organizational information.
An extranet is a network that is limited in scope to a single organization or entity and also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities—a company's customers may be given access to some part of its intranet—while at the same time the customers may not be considered trusted from a security standpoint. Technically, an extranet may also be categorized as a CAN, MAN, WAN, or other type of network, although an extranet cannot consist of a single LAN; it must have at least one connection with an external network.

[edit] Internet

The Internet is a global system of interconnected governmental, academic, corporate, public, and private computer networks. It is based on the networking technologies of the Internet Protocol Suite. It is the successor of the Advanced Research Projects Agency Network (ARPANET) developed by DARPA of the United States Department of Defense. The Internet is also the communications backbone underlying the World Wide Web (WWW).
Participants in the Internet use a diverse array of methods of several hundred documented, and often standardized, protocols compatible with the Internet Protocol Suite and an addressing system (IP addresses) administered by the Internet Assigned Numbers Authority and address registries. Service providers and large enterprises exchange information about the reachability of their address spaces through the Border Gateway Protocol (BGP), forming a redundant worldwide mesh of transmission paths.

[edit] Network topology

[edit] Common layouts

A network topology is the layout of the interconnections of the nodes of a computer network. Common layouts are:
  • A bus network: all nodes are connected to a common medium along this medium. This was the layout used in the original Ethernet, called 10BASE5 and 10BASE2.
  • A star network: all nodes are connected to a special central node. This is the typical layout found in a Wireless LAN, where each wireless client connects to the central Wireless access point.
  • A ring network: each node is connected to its left and right neighbour node, such that all nodes are connected and that each node can reach each other node by traversing nodes left- or rightwards. The Fiber Distributed Data Interface (FDDI) made use of such a topology.
  • A mesh network: each node is connected to an arbitrary number of neighbours in such a way that there is at least one traversal from any node to any other.
  • A fully connected network: each node is connected to every other node in the network.
Note that the physical layout of the nodes in a network may not necessarily reflect the network topology. As an example, with FDDI, the network topology is a ring (actually two counter-rotating rings), but the physical topology is a star, because all neighboring connections are routed via a central physical location.

[edit] Overlay network

An overlay network is a virtual computer network that is built on top of another network. Nodes in the overlay are connected by virtual or logical links, each of which corresponds to a path, perhaps through many physical links, in the underlying network. The topology of the overlay network may (and often does) differ from that of the underlying one.
A sample overlay network: IP over SONET over Optical
For example, many peer-to-peer networks are overlay networks because they are organized as nodes of a virtual system of links run on top of the Internet. The Internet was initially built as an overlay on the telephone network.[14]
The most striking example of an overlay network, however, is the Internet itself: At the IP layer, each node can reach any other by a direct connection to the desired IP address, thereby creating a fully connected network; the underlying network, however, is composed of a mesh-like interconnect of subnetworks of varying topologies (and, in fact, technologies). Address resolution and routing are the means which allows the mapping of the fully connected IP overlay network to the underlying ones.
Overlay networks have been around since the invention of networking when computer systems were connected over telephone lines using modems, before any data network existed.
Another example of an overlay network is a distributed hash table, which maps keys to nodes in the network. In this case, the underlying network is an IP network, and the overlay network is a table (actually a map) indexed by keys.
Overlay networks have also been proposed as a way to improve Internet routing, such as through quality of service guarantees to achieve higher-quality streaming media. Previous proposals such as IntServ, DiffServ, and IP Multicast have not seen wide acceptance largely because they require modification of all routers in the network.[citation needed] On the other hand, an overlay network can be incrementally deployed on end-hosts running the overlay protocol software, without cooperation from Internet service providers. The overlay has no control over how packets are routed in the underlying network between two overlay nodes, but it can control, for example, the sequence of overlay nodes a message traverses before reaching its destination.
For example, Akamai Technologies manages an overlay network that provides reliable, efficient content delivery (a kind of multicast). Academic research includes end system multicast and overcast for multicast; RON (resilient overlay network) for resilient routing; and OverQoS for quality of service guarantees, among others.

[edit] Basic hardware components

Main article: Networking hardware
Apart from the physical communications media themselves as described above, networks comprise additional basic hardware building blocks interconnecting their terminals, such as network interface cards (NICs), hubs, bridges, switches, and routers.

[edit] Network interface cards

A network card, network adapter, or NIC (network interface card) is a piece of computer hardware designed to allow computers to physically access a networking medium. It provides a low-level addressing system through the use of MAC addresses.
Each Ethernet network interface has a unique MAC address which is usually stored in a small memory device on the card, allowing any device to connect to the network without creating an address conflict. Ethernet MAC addresses are composed of six octets. Uniqueness is maintained by the IEEE, which manages the Ethernet address space by assigning 3-octet prefixes to equipment manufacturers. The list of prefixes is publicly available. Each manufacturer is then obliged to both use only their assigned prefix(es) and to uniquely set the 3-octet suffix of every Ethernet interface they produce.

Repeaters and hubs

A repeater is an electronic device that receives a signal, cleans it of unnecessary noise, regenerates it, and retransmits it at a higher power level, or to the other side of an obstruction, so that the signal can cover longer distances without degradation. In most twisted pair Ethernet configurations, repeaters are required for cable that runs longer than 100 meters. A repeater with multiple ports is known as a hub. Repeaters work on the Physical Layer of the OSI model. Repeaters require a small amount of time to regenerate the signal. This can cause a propagation delay which can affect network communication when there are several repeaters in a row. Many network architectures limit the number of repeaters that can be used in a row (e.g. Ethernet's 5-4-3 rule).
Today, repeaters and hubs have been made mostly obsolete by switches (see below).

[edit] Bridges

A network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges broadcast to all ports except the port on which the broadcast was received. However, bridges do not promiscuously copy traffic to all ports, as hubs do, but learn which MAC addresses are reachable through specific ports. Once the bridge associates a port and an address, it will send traffic for that address to that port only.
Bridges learn the association of ports and addresses by examining the source address of frames that it sees on various ports. Once a frame arrives through a port, its source address is stored and the bridge assumes that MAC address is associated with that port. The first time that a previously unknown destination address is seen, the bridge will forward the frame to all ports other than the one on which the frame arrived.
Bridges come in three basic types:
  • Local bridges: Directly connect LANs
  • Remote bridges: Can be used to create a wide area network (WAN) link between LANs. Remote bridges, where the connecting link is slower than the end networks, largely have been replaced with routers.
  • Wireless bridges: Can be used to join LANs or connect remote stations to LANs.


A network switch is a device that forwards and filters OSI layer 2 datagrams (chunks of data communication) between ports (connected cables) based on the MAC addresses in the packets.[15] A switch is distinct from a hub in that it only forwards the frames to the ports involved in the communication rather than all ports connected. A switch breaks the collision domain but represents itself as a broadcast domain. Switches make forwarding decisions of frames on the basis of MAC addresses. A switch normally has numerous ports, facilitating a star topology for devices, and cascading additional switches.[16] Some switches are capable of routing based on Layer 3 addressing or additional logical levels; these are called multi-layer switches. The term switch is used loosely in marketing to encompass devices including routers and bridges, as well as devices that may distribute traffic on load or by application content (e.g., a Web URL identifier).

[edit] Routers

A router is an internetworking device that forwards packets between networks by processing information found in the datagram or packet (Internet protocol information from Layer 3 of the OSI Model). In many situations, this information is processed in conjunction with the routing table (also known as forwarding table). Routers use routing tables to determine what interface to forward packets (this can include the "null" also known as the "black hole" interface because data can go into it, however, no further processing is done for said data).

[edit] Firewalls

A firewall is an important aspect of a network with respect to security. It typically rejects access requests from unsafe sources while allowing actions from recognized ones. The vital role firewalls play in network security grows in parallel with the constant increase in 'cyber' attacks for the purpose of stealing/corrupting data, planting viruses, etc.

Network performance

Main article: network performance
Network performance refers to the service quality of a telecommunications product as seen by the customer. It should not be seen merely as an attempt to get "more through" the network.
The following list gives examples of Network Performance measures for a circuit-switched network and one type of packet-switched network, viz. ATM:
  • Circuit-switched networks: In circuit switched networks, network performance is synonymous with the grade of service. The number of rejected calls is a measure of how well the network is performing under heavy traffic loads.[17] Other types of performance measures can include noise, echo and so on.
There are many different ways to measure the performance of a network, as each network is different in nature and design. Performance can also be modelled instead of measured; one example of this is using state transition diagrams to model queuing performance in a circuit-switched network. These diagrams allow the network planner to analyze how the network will perform in each state, ensuring that the network will be optimally designed.[19]

Network security

Main article: network security
In the field of networking, the area of network security[20] consists of the provisions and policies adopted by the network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of the computer network and network-accessible resources. Network security is the authorization of access to data in a network, which is controlled by the network administrator. Users are assigned an ID and password that allows them access to information and programs within their authority. Network Security covers a variety of computer networks, both public and private that are used in everyday jobs conducting transactions and communications among businesses, government agencies and individuals.

Network resilience

Main article: resilience (network)
In computer networking: “Resilience is the ability to provide and maintain an acceptable level of service in the face of faults and challenges to normal operation.”[21]

[edit] Views of networks

Users and network administrators typically have different views of their networks. Users can share printers and some servers from a workgroup, which usually means they are in the same geographic location and are on the same LAN, whereas a Network Administrator is responsible to keep that network up and running. A community of interest has less of a connection of being in a local area, and should be thought of as a set of arbitrarily located users who share a set of servers, and possibly also communicate via peer-to-peer technologies.
Network administrators can see networks from both physical and logical perspectives. The physical perspective involves geographic locations, physical cabling, and the network elements (e.g., routers, bridges and application layer gateways) that interconnect the physical media. Logical networks, called, in the TCP/IP architecture, subnets, map onto one or more physical media. For example, a common practice in a campus of buildings is to make a set of LAN cables in each building appear to be a common subnet, using virtual LAN (VLAN) technology.
Both users and administrators will be aware, to varying extents, of the trust and scope characteristics of a network. Again using TCP/IP architectural terminology, an intranet is a community of interest under private administration usually by an enterprise, and is only accessible by authorized users (e.g. employees).[22] Intranets do not have to be connected to the Internet, but generally have a limited connection. An extranet is an extension of an intranet that allows secure communications to users outside of the intranet (e.g. business partners, customers).[22]
Unofficially, the Internet is the set of users, enterprises, and content providers that are interconnected by Internet Service Providers (ISP). From an engineering viewpoint, the Internet is the set of subnets, and aggregates of subnets, which share the registered IP address space and exchange information about the reachability of those IP addresses using the Border Gateway Protocol. Typically, the human-readable names of servers are translated to IP addresses, transparently to users, via the directory function of the Domain Name System (DNS).
Over the Internet, there can be business-to-business (B2B), business-to-consumer (B2C) and consumer-to-consumer (C2C) communications. Especially when money or sensitive information is exchanged, the communications are apt to be secured by some form of communications security mechanism. Intranets and extranets can be securely superimposed onto the Internet, without any access by general Internet users and administrators, using secure Virtual Private Network (VPN) technology.

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