Computer Networking Presenntation

8/8/2019 Computer Networking Presenntation

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Computer networking

From Wikipedia, the free encyclopediaJump to: navigation , search This article is about computer networking, the discipline of engineering computer networks. For the article on computer networks, see Computer network ."Datacom" redirects here. For other uses, see Datacom (disambiguation) .

Network cards such as this one can transmit and receive data at high rates over various types of network cables. This card is a 'Combo' card which supportsthree cabling standards.

Computer networking or Data communications (Datacom ) is theengineering discipline concerned with the communication between computer systems or devices . A computer network is any set of computers or devicesconnected to each other with the ability to exchange data. [1] Computer networking is sometimes considered a sub-discipline of telecommunications ,computer science , information technology and/or computer engineering sinceit relies heavily upon the theoretical and practical application of thesescientific and engineering disciplines. The three types of networks are: theInternet , the intranet , and the extranet . Examples of different network methodsare:

y L ocal area network (L AN), which is usually a small network constrainedto a small geographic area. An example of a L AN would be a computer network within a building.

y M etropolitan area network (M AN), which is used for medium size area.examples for a city or a state.

y Wide area network (WAN) that is usually a larger network that covers alarge geographic area.

y Wireless L ANs and WANs (W L AN & WWAN) are the wireless

equivalent of the L AN and WAN.

All networks are interconnected to allow communication with a variety of different kinds of media, including twisted-pair copper wire cable, coaxialcable , optical fiber , power lines and various wireless technologies. [2] Thedevices can be separated by a few meters (e.g. via Bluetooth ) or nearlyunlimited distances (e.g. via the interconnections of the Internet[3] ).


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Networking, routers , routing protocols , and networking over the publicInternet have their specifications defined in documents called RFCs .[4]

Contents[hide ]

y 1 Views of networks y 2 History of computer networks y 3 Networking methods

y 3.1 L ocal area network ( L AN) y 3.2 Wide area network (WAN) y 3.3 Wireless networks (W L AN, WWAN)

y 4 Network topology y 5 See also y 6 References y 7 External links

Views of networks

U sers and network administrators typically have different views of their networks. U sers can share printers and some servers from a workgroup, whichusually means they are in the same geographic location and are on the sameL AN. A [community-of-interest network community of interest]has less of aconnection 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 alsocommunicate 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. L ogical networks, called, inthe 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 L ANcables in each building appear to be a common subnet, using virtual L AN(V L AN) technology.


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Both users and administrators will be aware, to varying extents, of the trustand scope characteristics of a network. Again using TCP/IP architecturalterminology, an intranet is a community of interest under privateadministration usually by an enterprise, and is only accessible by authorizedusers (e.g. employees). [5 ] Intranets do not have to be connected to theInternet, but generally have a limited connection. An extranet is an extensionof an intranet that allows secure communications to users outside of theintranet (e.g. business partners, customers). [5 ]

U nofficially, the Internet is the set of users, enterprises, and content providersthat are interconnected by Internet Service Providers (ISP). From anengineering viewpoint, the Internet is the set of subnets, and aggregates of subnets, which share the registered IP address space and exchangeinformation about the reachability of those IP addresses using the Border

Gateway Protocol . Typically, the human-readable names of servers aretranslated 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, thecommunications are apt to be secured by some form of communicationssecurity mechanism. Intranets and extranets can be securely superimposedonto the Internet, without any access by general Internet users, using secureVirtual Private Network (VPN) technology.When used for gaming one computer will need to be the server while theothers play through it

History of computer networks

Before the advent of computer networks that were based upon some type of telecommunications system, communication between calculation machinesand early computers was performed by human users by carrying instructions

between them. M any of the social behaviors seen in today's Internet were

demonstrably present in the nineteenth century and arguably in even earlier networks using visual signals.

In September 1940 George Stibitz used a teletype machine to sendinstructions for a problem set from his M odel at Dartmouth College in NewHampshire to his Complex Number Calculator in New York and receivedresults back by the same means. L inking output systems like teletypes to


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computers was an interest at the Advanced Research Projects Agency (ARPA)when, in 19 6 2, J.C.R. L icklider was hired and developed a working group hecalled the "Intergalactic Network" Bold text , a precursor to the ARPANet.

In 19 6 4, researchers at Dartmouth developed the Dartmouth Time SharingSystem for distributed users of large computer systems. The same year, atM IT, a research group supported by General Electric and Bell L abs used acomputer DEC's to route and manage telephone connections.

Throughout the 19 6 0s L eonard Kleinrock, Paul Baran and Donald Daviesindependently conceptualized and developed network systems which useddatagrams or packets that could be used in a network between computer systems.

1965 Thomas M errill and L awrence G. Roberts created the first wide areanetwork (WAN).

Networking methods

One way to categorize computer networks is by their geographic scope,although many real-world networks interconnect L ocal Area Networks (L AN)via Wide Area Networks (WAN) and wireless wide area networks (WWAN).These three (broad) types are:

Local area network (LA N)

A local area network is a network that spans a relatively small space and provides services to a small number of people.A peer-to-peer or client-server method of networking may be used. A peer-to-

peer network is where each client shares their resources with other workstations in the network. Examples of peer-to-peer networks are: Smalloffice networks where resource use is minimal and a home network. A client-

server network is where every client is connected to the server and each other.Client-server networks use servers in different capacities.

These can be classified into two types:

1. Single-service servers


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2. Print servers

The server performs one task such as file server, while other servers can notonly perform in the capacity of file servers and print servers, but also canconduct calculations and use them to provide information to clients(Web/Intranet Server). Computers may be connected in many different ways,including Ethernet cables, Wireless networks, or other types of wires such as

power lines or phone lines.

The ITU -T G.hn standard is an example of a technology that provides high-speed (up to 1 Gbit/s) local area networking over existing home wiring ( power lines , phone lines and coaxial cables ).

W ide area network ( W AN)

A wide area network is a network where a wide variety of resources aredeployed across a large domestic area or internationally. An example of this isa multinational business that uses a WAN to interconnect their offices indifferent countries. The largest and best example of a WAN is the Internet ,which is a network composed of many smaller networks. The Internet isconsidered the largest network in the world. [6 ]. The PSTN (Public SwitchedTelephone Network) also is an extremely large network that is converging touse Internet technologies, although not necessarily through the public Internet.A Wide Area Network involves communication through the use of a wide

range of different technologies. These technologies include Point-to-Point WANs such as Point-to-Point Protocol (PPP) and High- L evel Data L ink Control ( HD L C), Frame Relay , AT M (Asynchronous Transfer M ode) andSonet (Synchronous Optical Network). The difference between the WANtechnologies is based on the switching capabilities they perform and the speedat which sending and receiving bits of information (data) occur.


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W ireless networks ( W LA N, WW AN)

A wireless network is basically the same as a L AN or a WAN but there are nowires between hosts and servers. The data is transferred over sets of radiotransceivers. These types of networks are beneficial when it is too costly or inconvenient to run the necessary cables. For more information, see WirelessL AN and Wireless wide area network . The media access protocols for L ANscome from the IEEE .The most common IEEE 802.11 W L ANs cover, depending on antennas,ranges from hundreds of meters to a few kilometers. For larger areas, either communications satellites of various types, cellular radio, or wireless localloop ( IEEE 802.1 6 ) all have advantages and disadvantages. Depending on thetype of mobility needed, the relevant standards may come from the IETF or the ITU .

Network topology

The network topology defines the way in which computers, printers, and other devices are connected, physically and logically. A network topology describesthe layout of the wire and devices as well as the paths used by datatransmissions.

Network topology has two types:

y Physicaly L ogical

Commonly used topologies include:y Busy Star y Tree (hierarchical)y L inear


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y Ringy M esh

y partially connectedy fully connected (sometimes known as fully redundant )

The network topologies mentioned above are only a general representation of the kinds of topologies used in computer network and are considered basictopologies

See also

Book:Computer Networking

Books are collections of articles that can bedownloaded or ordered in print.

y Data transmission y Digital communications y Communication network y Network architecture y Data interventions


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R eferences

1. ^ http://www.atis.org/tg2k/_computer_network.html Computer network definition

2. ^ http://www.bellevuelinux.org/network.html Computer networks defined. 3. ^ Interplanetary Internet , 2000 Third Annual International Symposium on

Advanced Radio Technologies, A. Hooke,September 2000 4. ^ The Internet Standards Process -- Revision 3 , RFC 202 6 , rushawn o wright ,

October 199 6 . 5. ^ a b RFC 2 5 47 6. ^

http://www.pcmag.com/encyclopedia_term/0,2 5 42,t=internet&j= 5 4184,00.asp "internet" defined

y Andrew S. Tanenbaum , Computer Networks (ISBN 0-13-34994 5 -6 ). y Important publications in computer networks y Vinton G. Cerf "Software: Global Infrastructure for the 21st Century" y M eyers, M ike, "M ike M eyers' Certifcation Passport: Network+" ISBN

007 225 348 7 " y Odom, Wendall , "CCNA Certification Guide" y Network Communication Architecture and Protocols: OSI Network

Architecture 7 L ayers M odel.

Documents

Computer Networking Presenntation