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Typical server-based communications systems do not include end-to-end encryption. reference
References
^ Computer network definition, archived from the original on 2012-01-21, retrieved 2011-11-12
^ “История о том, как пионер кибернетики оказался не нужен СССР” [The story of how a cybernetics pioneer became unnecessary to the USSR]. ria.ru (in Russian). МИА «Россия сегодня». 2010-08-09. Retrieved 2015-03-04. Главным делом жизни Китова, увы, не доведенным до практического воплощения, можно считать разработку плана создания компьютерной сети (Единой государственной сети вычислительных центров – ЕГСВЦ) для управления народным хозяйством и одновременно для решения военных задач. Этот план Анатолий Иванович предложил сразу в высшую инстанцию, направив в январе 1959 года письмо генсеку КПСС Никите Хрущеву. Не получив ответа (хотя начинание на словах было поддержано в различных кругах), осенью того же года он заново направляет на самый верх письмо, приложив к нему 200-страничный детальный проект, получивший название ‘Красной книги’. [One can regard the magnum opus of Kitov’s career as his elaboration of the plan – unfortunately never brought into practical form – for the establishment of a computer network (the Unified State Network of Computer Centres – EGSVTs) for the control of the national economy and simultaneously for the resolution of military tasks. Anatolii Ivanovich presented this plan directly to the highest levels, sending a letter in January 1959 to the General Secretary of the Communist Party of the Soviet Union Nikita Khrushchev. Not receiving a reply (although supported in various circles), in the autumn of the same year he again sent a letter to the very top, appending a 200-page detailed project plan, called the ‘Red Book’]
^ Isaacson, Walter (2014). The Innovators: How a Group of Hackers, Geniuses, and Geeks Created the Digital Revolution. Simon and Schuster. pp. 237–246.
^ “Inductee Details – Paul Baran”. National Inventors Hall of Fame. Retrieved 6 September 2017.
^ “Inductee Details – Donald Watts Davies”. National Inventors Hall of Fame. Retrieved 6 September 2017.
^ Roberts, Larry; Marrill, Tom (October 1966). Toward a Cooperative Network of Time-Shared Computers. Fall AFIPS Conference.
^ Chris Sutton. “Internet Began 35 Years Ago at UCLA with First Message Ever Sent Between Two Computers”. UCLA. Archived from the original on March 8, 2008.
^ Gillies, James; Cailliau, Robert (2000). How the Web was Born: The Story of the World Wide Web. Oxford University Press. p. 25. ISBN 0192862073.
^ C. Hempstead; W. Worthington (2005). Encyclopedia of 20th-Century Technology. Routledge.
^ Bennett, Richard (September 2009). “Designed for Change: End-to-End Arguments, Internet Innovation, and the Net Neutrality Debate” (PDF). Information Technology and Innovation Foundation. p. 11. Retrieved 11 September 2017.
^ Ethernet: Distributed Packet Switching for Local Computer Networks Archived 2007-08-07 at the Wayback Machine., Robert M. Metcalfe and David R. Boggs, Communications of the ACM (pp 395–404, Vol. 19, No. 5), July 1976.
^ a b Spurgeon, Charles E. (2000). Ethernet The Definitive Guide. O’Reilly & Associates. ISBN 1-56592-660-9.
^ [1], The Disadvantages of Wired Technology, Laura Acevedo, Demand Media.
^ “Bergen Linux User Group’s CPIP Implementation”. Blug.linux.no. Retrieved 2014-03-01.
^ A. Hooke (September 2000), Interplanetary Internet (PDF), Third Annual International Symposium on Advanced Radio Technologies, archived from the original (PDF) on 2012-01-13, retrieved 2011-11-12
^ “Define switch”. WWW.Wikipedia.com. Retrieved April 8, 2008.
^ “What bridge devices and bridging do for computer networks”.
^ a b D. Andersen; H. Balakrishnan; M. Kaashoek; R. Morris (October 2001), Resilient Overlay Networks, Association for Computing Machinery, retrieved 2011-11-12
^ “End System Multicast”. project web site. Carnegie Mellon University. Archived from the original on February 21, 2005. Retrieved May 25, 2013.
^ For an interesting write-up of the technologies involved, including the deep stacking of communica
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Typical server-based communications systems do not include end-to-end encryption.
Typical server-based communications systems do not include end-to-end encryption. These systems can only guarantee protection of communications between clients and servers, not between the communicating parties themselves. Examples of non-E2EE systems are Google Talk, Yahoo Messenger, Facebook, and Dropbox. Some such systems, for example LavaBit and SecretInk, have even described themselves as offering “end-to-end” encryption when they do not. Some systems that normally offer end-to-end encryption have turned out to contain a back door that subverts negotiation of the encryption key between the communicating parties, for example Skype or Hushmail.

The end-to-end encryption paradigm does not directly address risks at the communications endpoints themselves, such as the technical exploitation of clients, poor quality random number generators, or key escrow. E2EE also does not address traffic analysis, which relates to things such as the identities of the end points and the times and quantities of messages that are sent.

Views of networks Edit

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 via the transmission media. Logical networks, called, in the TCP/IP architecture, subnets, map onto one or more transmission 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 are 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).[41] 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).[41]

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. When money or sensitive information is exchanged, the communications are apt to be protected 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.

See also Edit

Comparison of network diagram software
Cyberspace
History of the Internet
Network simulation
Network planning and design
Network traffic control
Minimum-Pairs Protocol

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Main article: Computer security Network security Network security

Network Security

Main article: Computer security
Network security
Network security consists of provisions and policies adopted by the network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of the computer network and its network-accessible resources.[36] 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 is used on a variety of computer networks, both public and private, to secure daily transactions and communications among businesses, government agencies and individuals.

Network surveillance Edit
Network surveillance is the monitoring of data being transferred over computer networks such as the Internet. The monitoring is often done surreptitiously and may be done by or at the behest of governments, by corporations, criminal organizations, or individuals. It may or may not be legal and may or may not require authorization from a court or other independent agency.

Computer and network surveillance programs are widespread today, and almost all Internet traffic is or could potentially be monitored for clues to illegal activity.

Surveillance is very useful to governments and law enforcement to maintain social control, recognize and monitor threats, and prevent/investigate criminal activity. With the advent of programs such as the Total Information Awareness program, technologies such as high speed surveillance computers and biometrics software, and laws such as the Communications Assistance For Law Enforcement Act, governments now possess an unprecedented ability to monitor the activities of citizens.[37]

However, many civil rights and privacy groups—such as Reporters Without Borders, the Electronic Frontier Foundation, and the American Civil Liberties Union—have expressed concern that increasing surveillance of citizens may lead to a mass surveillance society, with limited political and personal freedoms. Fears such as this have led to numerous lawsuits such as Hepting v. AT&T.[37][38] The hacktivist group Anonymous has hacked into government websites in protest of what it considers “draconian surveillance”.[39][40]

End to end encryption Edit
End-to-end encryption (E2EE) is a digital communications paradigm of uninterrupted protection of data traveling between two communicating parties. It involves the originating party encrypting data so only the intended recipient can decrypt it, with no dependency on third parties. End-to-end encryption prevents intermediaries, such as Internet providers or application service providers, from discovering or tampering with communications. End-to-end encryption generally protects both confidentiality and integrity.

Examples of end-to-end encryption include HTTPS for web traffic, PGP for email, OTR for instant messaging, ZRTP for telephony, and TETRA for radio.

Typical server-based communications systems do not include end-to-end encryption. These systems can only guarantee protection of communications between clients and servers, not between the communicating parties themselves. Examples of non-E2EE systems are Google Talk, Yahoo Messenger, Facebook, and Dropbox. Some such systems, for example LavaBit and SecretInk, have even described themselves as offering “end-to-end” encryption when they do not. Some systems that normally offer end-to-end encryption have turned out to contain a back door that subverts negotiation of the encryption key between the communicating parties, for example Skype or Hushmail.

The end-to-end encryption paradigm does not directly address risks at the communications endpoints themselves, such as the technical exploitation of clients, poor quality random number generators, or key escrow. E2EE also does not address traffic analysis, which relates to things such as the identities of the end points and the times and quantiti

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Quality of service Depending on the installation requirements, network performance is usually measured

Network performance

Quality of service
Depending on the installation requirements, network performance is usually measured by the quality of service of a telecommunications product. The parameters that affect this typically can include throughput, jitter, bit error rate and latency.

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.[32] Other types of performance measures can include the level of noise and echo.
ATM: In an Asynchronous Transfer Mode (ATM) network, performance can be measured by line rate, quality of service (QoS), data throughput, connect time, stability, technology, modulation technique and modem enhancements.[33]
There are many 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. For example, state transition diagrams are often used to model queuing performance in a circuit-switched network. The network planner uses these diagrams to analyze how the network performs in each state, ensuring that the network is optimally designed.[34]

Network congestion Edit
Network congestion occurs when a link or node is carrying so much data that its quality of service deteriorates. Typical effects include queueing delay, packet loss or the blocking of new connections. A consequence of these latter two is that incremental increases in offered load lead either only to small increase in network throughput, or to an actual reduction in network throughput.

Network protocols that use aggressive retransmissions to compensate for packet loss tend to keep systems in a state of network congestion—even after the initial load is reduced to a level that would not normally induce network congestion. Thus, networks using these protocols can exhibit two stable states under the same level of load. The stable state with low throughput is known as congestive collapse.

Modern networks use congestion control, congestion avoidance and traffic control techniques to try to avoid congestion collapse. These include: exponential backoff in protocols such as 802.11’s CSMA/CA and the original Ethernet, window reduction in TCP, and fair queueing in devices such as routers. Another method to avoid the negative effects of network congestion is implementing priority schemes, so that some packets are transmitted with higher priority than others. Priority schemes do not solve network congestion by themselves, but they help to alleviate the effects of congestion for some services. An example of this is 802.1p. A third method to avoid network congestion is the explicit allocation of network resources to specific flows. One example of this is the use of Contention-Free Transmission Opportunities (CFTXOPs) in the ITU-T G.hn standard, which provides high-speed (up to 1 Gbit/s) Local area networking over existing home wires (power lines, phone lines and coaxial cables).

For the Internet RFC 2914 addresses the subject of congestion control in detail.

Network resilience Edit
Network resilience is “the ability to provide and maintain an acceptable level of service in the face of faults and challenges to normal operation.”[35]

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Routing calculates good paths through a network for information to take.

Routing

Routing calculates good paths through a network for information to take. For example, from node 1 to node 6 the best routes are likely to be 1-8-7-6 or 1-8-10-6, as this has the thickest routes.
Routing is the process of selecting network paths to carry network traffic. Routing is performed for many kinds of networks, including circuit switching networks and packet switched networks.

In packet switched networks, routing directs packet forwarding (the transit of logically addressed network packets from their source toward their ultimate destination) through intermediate nodes. Intermediate nodes are typically network hardware devices such as routers, bridges, gateways, firewalls, or switches. General-purpose computers can also forward packets and perform routing, though they are not specialized hardware and may suffer from limited performance. The routing process usually directs forwarding on the basis of routing tables, which maintain a record of the routes to various network destinations. Thus, constructing routing tables, which are held in the router’s memory, is very important for efficient routing.

There are usually multiple routes that can be taken, and to choose between them, different elements can be considered to decide which routes get installed into the routing table, such as (sorted by priority):

Prefix-Length: where longer subnet masks are preferred (independent if it is within a routing protocol or over different routing protocol)
Metric: where a lower metric/cost is preferred (only valid within one and the same routing protocol)
Administrative distance: where a lower distance is preferred (only valid between different routing protocols)
Most routing algorithms use only one network path at a time. Multipath routing techniques enable the use of multiple alternative paths.

Routing, in a more narrow sense of the term, is often contrasted with bridging in its assumption that network addresses are structured and that similar addresses imply proximity within the network. Structured addresses allow a single routing table entry to represent the route to a group of devices. In large networks, structured addressing (routing, in the narrow sense) outperforms unstructured addressing (bridging). Routing has become the dominant form of addressing on the Internet. Bridging is still widely used within localized environments.

Network service Edit

Network services are applications hosted by servers on a computer network, to provide some functionality for members or users of the network, or to help the network itself to operate.

The World Wide Web, E-mail,[29] printing and network file sharing are examples of well-known network services. Network services such as DNS (Domain Name System) give names for IP and MAC addresses (people remember names like “nm.lan” better than numbers like “210.121.67.18”),[30] and DHCP to ensure that the equipment on the network has a valid IP address.[31]

Services are usually based on a service protocol that defines the format and sequencing of messages between clients and servers of that network service.

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Networks are typically managed by the organizations that own them.

Networks are typically managed by the organizations that own them. Private enterprise networks may use a combination of intranets and extranets. They may also provide network access to the Internet, which has no single owner and permits virtually unlimited global connectivity.

Intranet Edit
An intranet is a set of networks that are under the control of a single administrative entity. The intranet uses the IP protocol and IP-based tools such as web browsers and file transfer applications. The administrative entity limits use of the intranet to its authorized users. Most commonly, an intranet is the internal LAN of an organization. A large intranet typically has at least one web server to provide users with organizational information. An intranet is also anything behind the router on a local area network.

Extranet Edit
An extranet is a network that is also under the administrative control of a single organization, but supports a limited connection to a specific external network. For example, an organization may provide access to some aspects of its intranet to share data with its business partners or customers. These other entities are not necessarily trusted from a security standpoint. Network connection to an extranet is often, but not always, implemented via WAN technology.

Internetwork Edit
An internetwork is the connection of multiple computer networks via a common routing technology using routers.

Internet Edit

Partial map of the Internet based on the January 15, 2005 data found on opte.org. Each line is drawn between two nodes, representing two IP addresses. The length of the lines are indicative of the delay between those two nodes. This graph represents less than 30% of the Class C networks reachable.
The Internet is the largest example of an internetwork. It 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.

Darknet Edit
A darknet is an overlay network, typically running on the internet, that is only accessible through specialized software. A darknet is an anonymizing network where connections are made only between trusted peers — sometimes called “friends” (F2F)[27] — using non-standard protocols and ports.

Darknets are distinct from other distributed peer-to-peer networks as sharing is anonymous (that is, IP addresses are not publicly shared), and therefore users can communicate with little fear of governmental or corporate interference.[28]

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If Pride is an abomination to God and God rejects Proud people, how do I Detect Pride in my life and acts?*

*If Pride is an abomination to God and God rejects Proud people, how do I Detect Pride in my life and acts?*

1. If you don’t tremble at God’s word, you’re *Proud.*

2. When you seek vain glory, you’re *Proud.*

3. If you have any sense of self worth (you think you are better than someone else), you’re *Proud.*

4. If you normally look down on others, you’re *Proud.*

5. if you have any act of showmanship or always flaunting ur Wealth, ur Body with indecent clothes, you’re *Proud.*

6. If you don’t respect others (old or young), you’re *Proud.*

7. If you have any trace of selfishness, you’re *Proud*

8. If you get offended over little matters or minor issues, you’re *Proud.*

9. If you hate Corrections you’re *Proud.*

10. If you find it Difficult to Apologise, you’re *Proud.*

11. If you find it Difficult to Appreciate others, you’re *Proud.*

12. If you Hate Instructions, you’re *Proud.*

13. if you’re not always at ease to Accommodate others, you’re *Proud.*

14. If you get Irritated at others unnecessarily, you’re *Proud.*

15. If you lack the five magic words *(Please, Pardon me, I’m sorry, Thank you and Excuse me)*, you’re *Proud.*

16. If you always exaggerate, you’re *Proud.*

17. If you find it difficult to relate with people of lower class, you’re *Proud.*

18. If you find it difficult to adapt to certain conditions/situations, you’re *Proud.*

19. If you always want your Will, Decision, Reasoning and Desire to Supersede others, you’re *Proud.*

20. If you get offended when your Counsel is not taken, you are *Proud.*

21. If you get angry when you are not consulted or your Suggestion/Decision is Not Endorsed, you are *Proud.*

22. If you are not happy when others especially your juniors are Promoted or you don’t give Honour to whom Honour is due, you’re *Proud.*

23. If you are wise in your own eyes, you’re *Proud.*

24. If you don’t take wise and positive counsel/advice, you’re *Proud.*

25. If you lack the fear of God, you’re *Proud.*

26. If you don’t have Plan/Hope of making Heaven, you’re *Proud.*

27. If you lack the zeal to maintain Peace, you’re *Proud.*

28. If you always want people to Acknowledge your Presence and your Achievements in Public Places, you’re *Proud.*

29. If you treat the Poor with Disdain, you’re *Proud.*

30. If you Read this Piece and you Fail to *Humble yourself, Reflect on your Life Style or you Do not See this Piece as a Transparent Truth/Mirror, you’re **PROUD***

*May God Almighty Give us the Grace, to be Humble and to Treat People especially the Less Privileged RIGHT*

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SONET/SDH Synchronous optical networking computer institute
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.

Asynchronous Transfer Mode Edit
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.[20]

Cellular standards Edit
There are a number of different digital cellular standards, including: Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), cdmaOne, CDMA2000, Evolution-Data Optimized (EV-DO), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Digital Enhanced Cordless Telecommunications (DECT), Digital AMPS (IS-136/TDMA), and Integrated Digital Enhanced Network (iDEN).

A network can be characterized by its physical capacity or its organizational purpose. Use of the network, including user authorization and access rights, differ accordingly.

Nanoscale network
A nanoscale communication network has key components implemented at the nanoscale including message carriers and leverages physical principles that differ from macroscale communication mechanisms. Nanoscale communication extends communication to very small sensors and actuators such as those found in biological systems and also tends to operate in environments that would be too harsh for classical communication.[22]

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.[23] A wired PAN is usually constructed with USB and FireWire connections while technologies such as Bluetooth and infrared communication typically form a wireless PAN.

Local area network
A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as a home, school, office building, or closely positioned group of buildings. Each computer or device on the network is a node. Wired LANs are most likely based on Ethernet technology. Newer standards such as ITU-T G.hn also provide a way to create a wired LAN using existing wiring, such as coaxial cables, telephone lines, and power lines.[24]

The defining characteristics of a LAN, in contrast to a wide area network (WAN), include higher data transfer rates, limited geographic range, and lack of reliance on leased lines to provide connectivity. Current Ethernet or other IEEE 802.3 LAN technologies operate at data transfer rates up to 100 Gbit/s, standardized by IEEE in 2010.[25] Currently, 400 Gbit/s Ethernet is being developed.

A LAN can be connected to a WAN using a router.

Home area network
A home area network (HAN) is a residential LAN 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.

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A communication protocol is a set of rules for exchanging

A communication protocol is a set of rules for exchanging information over a network. In a protocol stack (also see the OSI model), each protocol leverages the services of the protocol layer below it, until the lowest layer controls the hardware which sends information across the media. The use of protocol layering is today ubiquitous across the field of computer networking. An important example of a protocol stack is HTTP (the World Wide Web protocol) running over TCP over IP (the Internet protocols) over IEEE 802.11 (the Wi-Fi protocol). 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 characteristics. They may be connection-oriented or connectionless, they may use circuit mode or packet switching, and they may use hierarchical addressing or flat addressing.

There are many communication protocols, a few of which are described below.

IEEE 802 Edit
IEEE 802 is a family of IEEE standards dealing with local area networks and metropolitan area networks. The complete IEEE 802 protocol suite provides a diverse set of networking capabilities. The protocols have a flat addressing scheme. They operate mostly at levels 1 and 2 of the OSI model.

For example, 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”.

Ethernet Edit
Ethernet, sometimes simply called LAN, is a family of protocols used in wired LANs, described by a set of standards together called IEEE 802.3 published by the Institute of Electrical and Electronics Engineers.

Wireless LAN Edit
Wireless LAN, also widely known as WLAN or WiFi, is probably the most well-known member of the IEEE 802 protocol family for home users today. It is standardized by IEEE 802.11 and shares many properties with wired Ethernet.

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

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computer network, or data network, is a digital telecommunications network

Overlay network Edit

A sample overlay network
An overlay network is a virtual computer network that is built on top of another network. Nodes in the overlay network are connected by virtual or logical links. Each link 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. For example, many peer-to-peer networks are overlay networks. They are organized as nodes of a virtual system of links that run on top of the Internet.[18]

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.

The most striking example of an overlay network is the Internet itself. The Internet itself was initially built as an overlay on the telephone network.[18] Even today, each Internet node can communicate with virtually any other through an underlying mesh of sub-networks of wildly different topologies and technologies. Address resolution and routing are the means that allow mapping of a fully connected IP overlay network to its underlying network.

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 network 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 that a message traverses before it reaches 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,[19] resilient routing and quality of service studies, among others.

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