A network protocol is an established set of rules that determine how data is transmitted between different devices in the same network. Essentially, it allows connected devices to communicate with each other, regardless of any differences in their internal processes, structure or design. Network protocols are the reason you can easily communicate with people all over the world, and thus play a critical role in modern digital communications.
Similar to the way that speaking the same language simplifies communication between two people, network protocols make it possible for devices to interact with each other because of predetermined rules built into devices’ software and hardware. Neither local area networks (LAN) nor wide area networks (WAN) could function the way they do today without the use of network protocols.
Network protocols take large-scale processes and break them down into small, specific tasks or functions. This occurs at every level of the network, and each function must cooperate at each level to complete the larger task at hand. The term protocol suite refers to a set of smaller network protocols working in conjunction with each other.
Network protocols are typically created according to industry standard by various networking or information technology organizations.
The following groups have defined and published different network protocols:
While network protocol models generally work in similar ways, each protocol is unique and operates in the specific way detailed by the organization that created it.
Who Uses Network Protocols?
Network protocols aren’t only relevant to certified network specialists or IT professionals. Billions of people use network protocols daily, whether they know it or not.
Every time you use the internet, you leverage network protocols. Though you may not know how network protocols work or how frequently you encounter them, they are necessary for using the internet or digital communications in any capacity.
List of Network Protocols
There are thousands of different network protocols, but they all perform one of three primary actions:
- Communication
- Network management
- Security
Each type is necessary to use network devices swiftly and safely, and they work together to facilitate that usage.
Communication
Communication protocols allow different network devices to communicate with each other. They are used in both analog and digital communications and can be used for important processes, ranging from transferring files between devices to accessing the internet.
Common types of communication protocols include the following:
- Automation: These protocols are used to automate different processes in both commercial and personal settings, such as in smart buildings, cloud technology or self-driving vehicles.
- Instant messaging: Instantaneous, text-based communications on smartphones and computers occur because of a number of different instant messaging network protocols.
- Routing: Routing protocols permit communication between routers and other network devices. There are also routing protocols specifically for ad hoc networks.
- Bluetooth: Ever-popular Bluetooth devices — including headsets, smartphones and computers — work due to a variety of different Bluetooth protocols.
- File transfer: If you have ever moved files from one device to another, either via a physical or digital medium, you’ve used file transfer protocols (FTP).
- Internet Protocol: Internet Protocol (IP) allows data to be sent between devices via the internet. The internet could not operate as it currently does without IP.
Network Management
Network management protocols define and describe the various procedures needed to effectively operate a computer network. These protocols affect various devices on a single network — including computers, routers and servers — to ensure each one, and the network as a whole, perform optimally.
The functions of network management protocols include the following:
- Connection: These protocols establish and maintain stable connections between different devices on the same network.
- Link aggregation: Link aggregation protocols allow you to combine multiple network connections into one link between two devices. This works to increase the strength of the connection and helps sustain the connection should one of the links fail.
- Troubleshooting: Troubleshooting protocols allow network administrators to identify errors affecting the network, evaluate the quality of the network connection, and determine how administrators can fix any issues.
Security
Security protocols, also called cryptographic protocols, work to ensure that the network and the data sent over it are protected from unauthorized users.
Common functions of security network protocols include the following:
- Encryption: Encryption protocols protect data and secure areas by requiring users to input a secret key or password in order to access that information.
- Entity Authentication: Entity authentication protocols create a system that requires different devices or users on a network to verify their identity before accessing secure areas.
- Transportation: Transportation security protocols protect data while it is transported from one network device to another.
Network Protocol Example
Whether you know it or not, you’ve absolutely encountered network protocols when using electronic devices – and some of them are readily identifiable.
Here are a few examples of the most commonly used network protocols:
- Hypertext Transfer Protocol (HTTP): This Internet Protocol defines how data is transmitted over the internet and determines how web servers and browsers should respond to commands. This protocol (or its secure counterpart, HTTPS) appears at the beginning of various URLs or web addresses online.
- Secure Socket Shell (SSH): This protocol provides secure access to a computer, even if it’s on an unsecured network. SSH is particularly useful for network administrators who need to manage different systems remotely.
- Short Message Service (SMS): This communications protocol was created to send and receive text messages over cellular networks. SMS refers exclusively to text-based messages. Pictures, videos or other media require Multimedia Messaging Service (MMS), an extension of the SMS protocol.
Network protocols do not simply define how devices and processes work; they define how devices and processes work together. Without these predetermined conventions and rules, the internet would lack the necessary infrastructure it needs to be functional and useable. Network protocols are the foundation of modern communications, without which the digital world could not stand.
CompTIA Network+ covers computer networking topics including network protocols. Download the exam objectivesto see all the topics covered by this IT certification.
Read more about Computer Networks.
The Internet is the worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government networks, which together carry various information and services, such as electronic mail, online chat, file transfer, and the interlinked Web pages and other documents of the World Wide Web.
Terminology: Internet vs. Web
The Internet and the World Wide Web are not synonymous: the Internet is a collection of interconnected computer networks, linked by copper wires, fibre-optic cables, wireless connections, etc.; the Web is a collection of interconnected documents and other resources, linked by hyperlinks and URLs. The World Wide Web is accessible via the Internet, as are many other services including e-mail, file sharing, and others described below.
The best way to define and distinguish between these terms is to understand the Internet protocol suite. This collection of protocols is organized into layers such that each layer provides the foundation and the services required by the layer above. In this conception, the term Internet refers to computer networks that all communicate with IP (Internet protocol) and TCP (transfer control protocol). Once this networking structure is established, then other protocols can run “on top.” These other protocols are sometimes called services or applications. Hypertext transfer protocol, or HTTP, is an application layer protocol that links billions of files together into the World Wide Web.
Creation of the Internet
The Internet is the worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government networks, which together carry various information and services, such as electronic mail, online chat, file transfer, and the interlinked Web pages and other documents of the World Wide Web.
The USSR's launch of Sputnik spurred the United States to create the Advanced Research Projects Agency (ARPA, later known as the Defense Advanced Research Projects Agency, or DARPA) in February 1958 to regain a technological lead. ARPA created the Information Processing Technology Office (IPTO) to further the research of the Semi Automatic Ground Environment (SAGE) program, which had networked country-wide radar systems together for the first time. J. C. R. Licklider was selected to head the IPTO, and saw universal networking as a potential unifying human revolution.
In 1950, Licklider moved from the Psycho-Acoustic Laboratory at Harvard University to MIT where he served on a committee that established MIT Lincoln Laboratory. He worked on the SAGE project. In 1957 he became a Vice President at BBN, where he bought the first production PDP-1 computer and conducted the first public demonstration of time-sharing.
Licklider recruited Lawrence Roberts to head a project to implement a network, and Roberts based the technology on the work of Paul Baran who had written an exhaustive study for the U.S. Air Force that recommended packet switching (as opposed to Circuit switching) to make a network highly robust and survivable. After much work, the first node went live at UCLA on October 29, 1969 on what would be called the ARPANET, one of the "eve" networks of today's Internet. Following on from this, the British Post Office, Western Union International and Tymnet collaborated to create the first international packet switched network, referred to as the International Packet Switched Service (IPSS), in 1978. This network grew from Europe and the US to cover Canada, Hong Kong and Australia by 1981.
The first TCP/IP wide area network was operational by 1 January 1983, when the United States' National Science Foundation (NSF) constructed a university network backbone that would later become the NSFNet. (This date is held by some to be technically that of the birth of the Internet.) It was then followed by the opening of the network to commercial interests in 1985. Important, separate networks that offered gateways into, then later merged with, the NSFNet include Usenet, Bitnet and the various commercial and educational X.25 Compuserve and JANET. Telenet (later called Sprintnet), was a large privately-funded national computer network with free dialup access in cities throughout the U.S. that had been in operation since the 1970s. This network eventually merged with the others in the 1990s as the TCP/IP protocol became increasingly popular. The ability of TCP/IP to work over these pre-existing communication networks, especially the international X.25 IPSS network, allowed for a great ease of growth. Use of the term "Internet" to describe a single global TCP/IP network originated around this time.
The network gained a public face in the 1990s. On August 6th, 1991 CERN, which straddles the border between France and Switzerland publicized the new World Wide Web project, two years after Tim Berners-Lee had begun creating HTML, HTTP and the first few Web pages at CERN.
An early popular Web browser was ViolaWWW based upon HyperCard. It was eventually replaced in popularity by the Mosaic Web Browser. In 1993 the National Centre for Supercomputing Applications at the University of Illinois at Urbana-Champaign released version 1.0 of Mosaic and by late 1994 there was growing public interest in the previously academic/technical Internet. By 1996 the word "Internet" was coming into common daily usage, frequently misused to refer to the World Wide Web.
Meanwhile, over the course of the decade, the Internet successfully accommodated the majority of previously existing public computer networks (although some networks such as FidoNet have remained separate). This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary open nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network.
Today's Internet
Aside from the complex physical connections that make up its infrastructure, the Internet is facilitated by bi- or multi-lateral commercial contracts (e.g., peering agreements), and by technical specifications or protocols that describe how to exchange data over the network. Indeed, the Internet is essentially defined by its interconnections and routing policies.
As of September 18, 2006, 1.09 billion people use the Internet according to Internet World Stats.
Internet protocols
In this context, there are three layers of protocols:
- At the lowest level is IP (Internet Protocol), which defines the datagrams or packets that carry blocks of data from one node to another. The vast majority of today's Internet uses version four of the IP protocol (i.e. IPv4), and although IPv6 is standardised, it exists only as "islands" of connectivity, and there are many ISPs who don't have any IPv6 connectivity at all.
- Next come TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) - the protocols by which one host sends data to another. The former makes a virtual 'connection', which gives some level of guarantee of reliability. The latter is a best-effort, connectionless transport, in which data packets that are lost in transit will not be re-sent.
- On top comes the application protocol. This defines the specific messages and data formats sent and understood by the applications running at each end of the communication.
Internet structure
There have been many analyses of the Internet and its structure. For example, it has been determined that the Internet IP routing structure and hypertext links of the World Wide Web are examples of scale-free networks.
Similar to the way the commercial Internet providers connect via Internet exchange points, research networks tend to interconnect into large subnetworks such as:
- GEANT
- GLORIAD
- Internet2
- JANET (the UK's Joint Academic Network aka UKERNA)
These in turn are built around relatively smaller networks. See also the list of academic computer network organizations
In network schematic diagrams, the Internet is often represented by a cloud symbol, into and out of which network communications can pass.
ICANN
The Internet Corporation for Assigned Names and Numbers (ICANN) is the authority that coordinates the assignment of unique identifiers on the Internet, including domain names, Internet protocol addresses, and protocol port and parameter numbers. A globally unified namespace (i.e., a system of names in which there is one and only one holder of each name) is essential for the Internet to function. ICANN is headquartered in Marina del Rey, California, but is overseen by an international board of directors drawn from across the Internet technical, business, academic, and non-commercial communities. The US government continues to have the primary role in approving changes to the root zone file that lies at the heart of the domain name system. Because the Internet is a distributed network comprising many voluntarily interconnected networks, the Internet, as such, has no governing body. ICANN's role in coordinating the assignment of unique identifiers distinguishes it as perhaps the only central coordinating body on the global Internet, but the scope of its authority extends only to the Internet's systems of domain names, Internet protocol addresses, and protocol port and parameter numbers.
On Nov. 16, 2005, the World Summit on the Information Society, held in Tunis, established the Internet Governance Forum (IGF) to discuss Internet-related issues.
Language
The most prevalent language for communication on the Internet is English. This may be a result of the Internet's origins, as well as English's role as the lingua franca. It may also be related to the poor capability of early computers to handle characters other than those in the basic Latin alphabet.
After English (30% of Web visitors) the most-requested languages on the World Wide Web are Chinese 14%, Japanese 8%, Spanish 8%, German 6%, and French 4% (from Internet World Stats, updated June 30, 2006).
By continent, 37% of the world's Internet users are based in Asia, 28% in Europe, and 22% in North America ( updated June 30, 2006).
The Internet's technologies have developed enough in recent years that good facilities are available for development and communication in most widely used languages. However, some glitches such as mojibake (incorrect display of foreign language characters, also known as krakozyabry) still remain.
Internet and the workplace
The Internet is allowing greater flexibility in working hours and location, especially with the spread of unmetered high-speed connections and Web applications.
Common uses of the Internet
The World Wide Web
Through keyword-driven Internet research using search engines, like Google, millions worldwide have easy, instant access to a vast and diverse amount of online information. Compared to encyclopedias and traditional libraries, the World Wide Web has enabled a sudden and extreme decentralization of information and data.
Many individuals and some companies and groups have adopted the use of "Web logs" or blogs, which are largely used as easily-updatable online diaries. Some commercial organizations encourage staff to fill them with advice on their areas of specialization in the hope that visitors will be impressed by the expert knowledge and free information, and be attracted to the corporation as a result. One example of this practice is Microsoft, whose product developers publish their personal blogs in order to pique the public's interest in their work.
For more information on the distinction between the World Wide Web and the Internet itself — as in everyday use the two are sometimes confused — see Dark internet where this is discussed in more detail.
Remote access
The Internet allows computer users to connect to other computers and information stores easily, wherever they may be across the world. They may do this with or without the use of security, authentication and encryption technologies, depending on the requirements.
This is encouraging new ways of working from home, collaboration and information sharing in many industries. An accountant sitting at home can audit the books of a company based in another country, on a server situated in a third country that is remotely maintained by IT specialists in a fourth. These accounts could have been created by home-working book-keepers, in other remote locations, based on information e-mailed to them from offices all over the world. Some of these things were possible before the widespread use of the Internet, but the cost of private, leased lines would have made many of them infeasible in practice.
An office worker away from his desk, perhaps the other side of the world on a business trip or a holiday, can open a remote desktop session into his normal office PC using a secure Virtual Private Network (VPN) connection via the Internet. This gives him complete access to all his normal files and data, including e-mail and other applications, while he is away.
This concept is also referred to by some network security people as the Virtual Private Nightmare, because it extends the secure perimeter of a corporate network into its employees' homes; this has been the source of some notable security breaches, but also provides security for the workers.
Collaboration
The low-cost and nearly instantaneous sharing of ideas, knowledge, and skills has made collaborative work dramatically easier. Not only can a group cheaply communicate and test, but the wide reach of the Internet allows such groups to easily form in the first place, even among niche interests. An example of this is the Free/Libre/Open-Source Software (FLOSS) movement in software development, such as Linux, Mozilla, and OpenOffice.org. Cooperation has been greatly eased in other fields, as well.
Internet 'chat', whether in the form of IRC 'chat rooms' or channels, or via instant messaging systems allow colleages to stay in touch in a very convenient way when working at their computers during the day. Messages can be send and viewed even more quickly and conveniently than via e-mail. Extension to these systems may allow files to be exchanged, 'whiteboard' drawings to be shared as well as voice and video contact between team members.
Version control systems allow collaborating teams to work on shared sets of documents without either accidentally overwriting each other's work or having members wait until they get 'sent' documents to be able to add their thoughts and changes.
File sharing
A computer file can be e-mailed to customers, colleagues and friends as an attachment. It can be uploaded to a Web site or FTP server for easy download by others. It can be put into a "shared location" or onto a file server for instant use by colleagues. The load of bulk downloads to many users can be eased by the use of " mirror" servers or peer-to-peer networks. In any of these cases, access to the file may be controlled by user authentication; the transit of the file over the Internet may be obscured by encryption and money may change hands before or after access to the file is given. The price can be paid by the remote charging of funds from, for example a credit card whose details are also passed - hopefully fully encrypted - across the Internet. The origin and authenticity of the file received may be checked by digital signatures or by MD5 or other message digests.
These simple features of the Internet, over a world-wide basis, are changing the basis for the production, sale, and distribution of anything that can be reduced to a computer file for transmission. This includes all manner of office documents, publications, software products, music, photography, video, animations, graphics and the other arts. This in turn is causing seismic shifts in each of the existing industry associations, such as the RIAA and MPAA in the United States, that previously controlled the production and distribution of these products in that country.
VoIP
VoIP stands for Voice over IP, where IP refers to the Internet Protocol that underlies all Internet communication. This phenomenon began as an optional two-way voice extension to some of the Instant Messaging systems that took off around the year 2000. In recent years many VoIP systems have become as easy to use and as convenient as a normal telephone. The benefit is that, as the Internet carries the actual voice traffic, VoIP can be free or cost much less than a normal telephone call, especially over long distances and especially for those with always-on ADSL or DSL Internet connections.
Thus VoIP is maturing into a viable alternative to traditional telephones. Interoperability between different providers has improved and the ability to call or receive a call from a traditional telephone is available. Simple inexpensive VoIP modems are now available that eliminate the need for a PC.
Voice quality can still vary from call to call but is often equal to and can even exceed that of traditional calls.
Remaining problems for VoIP include emergency telephone number dialing and reliability. Currently a few VoIP providers provide some 911 dialing but it is not universally available. Traditional phones are line powered and operate during a power failure, VoIP does not do so without a backup power source for the electronics.
Most VoIP providers offer unlimited national calling but the direction in VoIP is clearly toward global coverage with unlimited minutes for a low monthly fee.
VoIP has also become increasingly popular within the gaming world, as a form of communication between players. Popular gaming VoIP clients include Ventrilo and Teamspeak, and there are others available also.
Censorship
Some governments, such as those of Iran and the People's Republic of China restrict what people in their countries can access on the Internet, especially political and religious content. This is accomplished through software that filters domains and content so that they may not be easily accessed or obtained without elaborate circumvention.
Many countries have enacted laws making the possession or distribution of certain material, such as child pornography, illegal, but do not use filtering software.
There are many free and commercially available software programs with which a user can choose to block offensive Web sites on individual computers or networks, such as to limit a child's access to pornography or violence. See Content-control software.
Internet access
Common methods of home access include dial-up, landline broadband (over coaxial cable, fibre optic or copper wires), Wi-Fi, satellite and cell phones.
Public places to use the Internet include libraries and Internet cafes, where computers with Internet connections are available. There are also Internet access points in many public places such as airport halls and coffee shops, in some cases just for brief use while standing. Various terms are used, such as "public Internet kiosk", "public access terminal", and "Web payphone". Many hotels now also have public terminals, though these are usually fee based.
Wi-Fi provides wireless access to computer networks, and therefore can do so to the Internet itself. Hotspots providing such access include Wi-Fi-cafes, where a would-be user needs to bring their own wireless-enabled devices such as a laptop or PDA. These services may be free to all, free to customers only, or fee-based. A hotspot need not be limited to a confined location. The whole campus or park, or even the entire city can be enabled. Grassroots efforts have led to wireless community networks. Commercial WiFi services covering large city areas are in place in London, Vienna, San Francisco, Philadelphia, Chicago, Pittsburgh and other cities, including Toronto by the end of 2006. The Internet can then be accessed from such places as a park bench.
Apart from Wi-Fi, there have been experiments with proprietary mobile wireless networks like Ricochet, various high-speed data services over cellular phone networks, and fixed wireless services.
High-end mobile phones such as smartphones generally come with Internet access through the phone network. Web browsers such as Opera are available on these advanced handsets, which can also run a wide variety of other Internet software. More mobile phones have Internet access than PCs, though this is not as widely used. An internet access provider and protocol matrix differentiates the methods used to get online.
Leisure
The Internet has been a major source of leisure since before the World Wide Web, with entertaining social experiments such as MUDs and MOOs being conducted on university servers, and humor-related Usenet groups receiving much of the main traffic. Today, many Internet forums have sections devoted to games and funny videos; short cartoons in the form of Flash movies are also popular. Over 6 million people use blogs or message boards as a means of communication and for the sharing of ideas.
The pornography and gambling industries have both taken full advantage of the World Wide Web, and often provide a significant source of advertising revenue for other Web sites. Although many governments have attempted to put restrictions on both industries' use of the Internet, this has generally failed to stop their widespread popularity. A song in the Broadway musical show Avenue Q is titled " The Internet is for Porn" and refers to the popularity of this aspect of the internet.
One main area of leisure on the Internet is multiplayer gaming. This form of leisure creates communities, bringing people of all ages and origins to enjoy the fast-paced world of multiplayer games. These range from MMORPG to first-person shooters, from role-playing games to online gambling. This has revolutionized the way many people interact and spend their free time on the Internet.
While online gaming has been around since the 1970s, modern modes of online gaming began with services such as GameSpy and MPlayer, which players of games would typically subscribe to. Non-subscribers were limited to certain types of gameplay or certain games.
Many use the Internet to access and download music, movies and other works for their enjoyment and relaxation. As discussed above, there are paid and unpaid sources for all of these, using centralised servers and distributed peer-to-peer technologies. Discretion is needed as some of these sources take more care over the original artists' rights and over copyright laws than others.
Many use the World Wide Web to access news, weather and sports reports, to plan and book holidays and to find out more about their random ideas and casual interests.
People use chat, messaging and email to make and stay in touch with friends worldwide, sometimes in the same way as some previously had pen pals. Social networking Web sites like Friends Reunited and many others like them also put and keep people in contact for their enjoyment.
Cyberslacking has become a serious drain on corporate resources; the average UK employee spends 57 minutes a day surfing the Web at work, according to a study by Peninsula Business Services .
Complex architecture
Many computer scientists see the Internet as a "prime example of a large-scale, highly engineered, yet highly complex system". The Internet is extremely heterogeneous. (For instance, data transfer rates and physical characteristics of connections vary widely.) The Internet exhibits "emergent phenomena" that depend on its large-scale organization. For example, data transfer rates exhibit temporal self-similarity.
Marketing
The Internet has also become a large market for companies; some of the biggest companies today have grown by taking advantage of the efficient nature of low-cost advertising and commerce through the Internet; also known as e-commerce. It is the fastest way to spread information to a vast amount of people simultaneously. The Internet has also subsequently revolutionized shopping—for example; a person can order a CD online and receive it in the mail within a couple of days, or download it directly in some cases. The Internet has also greatly facilitated personalized marketing which allows a company to market a product to a specific person or a specific group of people more so than any other advertising medium.
Examples of personalized marketing include online communities such as Myspace, Friendster, and others which thousands of Internet users join to advertise themselves and make friends online. Many of these users are young teens and adolescents ranging from 13 to 25 years old. In turn, when they advertise themselves they advertise interests and hobbies, which online marketing companies can use as information as to what those users will purchase online, and advertise their own companies' products to those users.
A very ineffective way of advertising on the internet is through spamming an email with advertisements. This is ineffective because, now, most email providers offer protection against email spam. Most spam messages are sent automatically to everybody in the email database of the company/person that is spamming. This way of advertising is almost like using adware.
Adware is another ineffective way of advertising because most people simply close a popup window when it shows up, not bothering to read it.
The name Internet
Internet is traditionally written with a capital first letter, as it is a proper noun. The Internet Society, the Internet Engineering Task Force, the Internet Corporation for Assigned Names and Numbers, the World Wide Web Consortium, and several other Internet-related organizations use this convention in their publications.
Many newspapers, newswires, periodicals, and technical journals capitalize the term. Examples include the New York Times, the Associated Press, Time, The Times of India, Hindustan Times, and Communications of the ACM.
Others assert that the first letter should be written in lower case (internet). A significant number of publications use this form, including The Economist, the Canadian Broadcasting Corporation, the Financial Times, The Guardian, The Times, and The Sydney Morning Herald. As of 2005, many publications using internet appear to be located outside of North America—although one U.S. news source, Wired News, has adopted the lower case spelling.
Historically, Internet and internet have had different meanings, with internet being a contraction of internetwork or internetworking and Internet referring to the worldwide network. Under this distinction, the Internet is a particular internet, but the reverse does not apply. The distinction was evident in many RFCs, books, and articles from the 1980s and early 1990s (some of which, such as RFC 1918, refer to "internets" in the plural), but has recently fallen into disuse.
Significant Internet events
Malfunctions and attacks
- SQL Slammer worm — January 24, 2003
- 2002 DNS Backbone DDoS — October 22, 2002
- UUNet/Worldcom backbone difficulties — October 3, 2002
- Predicted Y2K Bug - January 1, 2000
- Morris worm — November 2, 1988