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NETWORK TOPOLOGY

Network Topology is, things that explains the geometric relationship between the basic elements of the network compiler, namely nodes, links, and the station. Network topology can be divided into five main categories as below.

1. Topology stars

Star topology is a form of network topologies in the form of convergence of the central node to each node or user. Star network topology including network topology with medium cost.Advantages
    * Damage to a single channel will only affect the channel network and the station adrift.
    * Security level is high.
    * Resistant to a busy network traffic.
    * Additions and reductions station can be done easily.Disadvantages
    * If the node was malfunctioning, then the entire network to a halt.Handling
    * The need for a backup center node set.

    * Ring network
    * Topology bus
    * Mesh topology
    * Topology treeEach type of topology on top of each has advantages and disadvantages. The selection of network topology based on network scale, cost, purpose, and users.

2. Topology is ring-shaped network topology circuit, each point is connected to two other points, such that forming a circular path to form a ring. In a ring topology, data communication can be disrupted if a single point of disturbance. FDDI networks anticipate this weakness by sending data in clockwise and counterclockwise with clockwise direction simultaneously.

3. On a bus topology network two unjung must end with a terminator. Barrel connector can be used to expand them. Network consists of only one cable channel using BNC cables. Who wants to connect to a computer network can be linked himself with mentap Ethernet over cable.
Linear Bus: This layout includes the general layout. One main cable connecting each node, the computers that access a single channel with the tip of the tip. Each node is connected to two other nodes, except the engine at one end of the cable, each node is only connected to one another. This topology is often found on client / server, where one of the machines on the network functioned as a File Server, which means that the machine is devoted only to the distribution of data and are not usually used for processing information.
Bus network installation is very simple, cheap and consist of a maximum of 5-7 computers. The difficulty often faced is the possibility of data collisions because the mechanism is relatively simple network and if one node is broken it will disrupt the entire network performance and traffic.
* Excellence is developing a network bus topology or adding new workstations can be done easily without disrupting the other workstations.* The weakness of this topology is that if there is interference along the cable, the center of the whole network will be disrupted.
Linear bus topology is a topology widely used in the mushrooming use of Coaxial cable. By using the T-Connector (with a 50ohm terminator on the end of the network), then the computer or other network device can easily be connected to one another. The main difficulty of using coaxial cables is difficult to measure whether the coaxial cable that is used completely matched or not. Because if not truly be measured properly will damage the NIC (network interface card) which is used and the network performance becomes constrained, not reaching maximum capacity. This topology is also frequently used in fiber-optic network with a base (which later merged with a star topology to connect with a client or a node.)

4. Network Topology Tree (Tree) network topologies are also known as multilevel network topology. This topology is usually used for interconnection between different central denganhirarki. To the lower hierarchy is described in the locations of low and increasingly higher up the hierarchy have. This type of network topology suitable for computer network systems.In tree networks, there are several levels of nodes (node). Central or higher level node, another node can set a lower level. Data sent to the central node first. For example to move from a computer with a node-3 node kekomputer-7 as well as in the figure, the data must pass through node-3, 5 and node-6 before ending at the node-7. Keungguluan network tree model like this is, can the formation of a group that is required at all times. For example, companies can form a group consisting of terminal accounts, as well as on other groups formed to terminal sales. The weakness is, if the node is higher then does not work, then the other group who are below it eventually also became ineffective. How the tree network is relatively slow.

5. Mesh topology is a form of relationship between devices whereby each device is connected directly to other devices on the network. Consequently, in a mesh topology each device can communicate directly with the target device (dedicated links).
Thus the maximum number of connections between devices on the network can be calculated bertopologi this mesh is n (n-1) / 2. Moreover, because every device can connect to other devices on the network, each device must have as many as n-1 Port Input / Output (I / O ports).Based on the above understanding, would be an example that if as many as 5 (five) computers will be connected in a mesh topology so that all connections between computers to function optimally, the necessary connection cables as much as five (5-1) / 2 = 10 cable connection, and each each computer must have a port I / O ports as much as 5-1 = 4 (see picture)

With this form of such relationship, mesh topology has several advantages, namely:
    * Relationship dedicated links guarantees direct data delivered to the destination computer without having to go through another computer so it can more quickly because one link is used exclusively for communicating with the destination computer only (not used beramai-ramai/sharing).
    * Having a robust nature, namely the event of disruption to computer connection A with computer B because of damage to the cable connections (links) between A and B, then the disturbance will not affect computer A connection with other computers.
    * Privacy and security in mesh topology is more reliable, because the communication that occurs between the two computers will not be accessible by other computers.
    * Facilitate the process of problem identification in the event of damage to connections between computers.
Nevertheless, the mesh topology is not without its shortcomings. Some deficiencies can be recorded as follows:
    * Requires a lot of cable and port I / O. more and more computers in a mesh topology is needed more and more cable links and I / O ports (see the formula computation needs of cable and port).
    * It also indicates that once the topology of this type * Because every computer must be connected directly with other computers then the installation and configuration becomes more difficult.
    * Number of cable used also suggests the need to allow space in the room where the computers are located.Based on the advantages and disadvantages, mesh topology is usually implemented on the main computers where each computer is the main form separate networks with different topologies (hybrid network).

THE INTERNET

What's the INTERNET anyway?? do u know?

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. It is a network of networks that consists of millions of private, public, academic, business, and government networks of local to global scope that are linked by a broad array of electronic and optical networking technologies. The Internet carries a vast array of information resources and services, most notably the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support electronic mail.

Most traditional communications media, such as telephone and television services, are reshaped or redefined using the technologies of the Internet, giving rise to services such as Voice over Internet Protocol (VoIP) and IPTV. Newspaper publishing has been reshaped into Web sites, blogging, and web feeds. The Internet has enabled or accelerated the creation of new forms of human interactions through instant messaging, Internet forums, and social networking sites.
The origins of the Internet reach back to research in the 1960s, both commissioned by the United States government to develop projects of its military agencies to build robust, fault-tolerant, and distributed computer networks as well as private research. This research and a period of civilian funding of a new U.S. backbone by the National Science Foundation, as well as private funding for commercial backbones spawned worldwide participation in the development of new networking technologies and led to the merger of many networks. The commercialization of an international network in the mid 1990s, and resulted in the following popularization of countless applications in virtually every aspect of modern human life. As of 2009, an estimated quarter of Earth's population uses the services of the Internet.
The Internet has no centralized governance in either technological implementation or policies for access and usage; each constituent network sets its own standards. Only the overreaching definitions of the two principal name spaces in the Internet, the Internet Protocol address space and the Domain Name System, are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers (ICANN). The technical underpinning and standardization of the core protocols (IPv4 and IPv6) is an activity of the Internet Engineering Task Force (IETF), a non-profit organization of loosely affiliated international participants that anyone may associate with by contributing technical expertise.

HISTORY
The Internet is a computer network established by the Department of Defense United States in 1969, through a project called ARPANET ARPA (Advanced Research Project Agency Network), where they demonstrated how the computer hardware and software-based UNIX, we can do within a short distance communication infinity through the phone line. ARPANET project designing the network, reliability, how much information can be transferred, and finally all the standards that they determine to be the forerunner to the development of a new protocol that is now known as TCP / IP (Transmission Control Protocol / Internet Protocol). The initial purpose of the project was for military purposes. At that time the United States Department of Defense (U.S. Department of Defense) create a system of computer networks that are spread by linking computers in areas vital to overcome the problem if there is a nuclear attack and to avoid any centralized information, which in the event of war can easily be destroyed.
At first ARPANET just simply connect the four sites are the Stanford Research Institute, University of California, Santa Barbara, University of Utah, where they form an integrated network in 1969, and in general the ARPANET was introduced in October 1972. Not long after the project is growing rapidly in all regions, and all universities in the country wants to join, thus making it difficult to set the ARPANET.
Therefore Manjadi ARPANET was split in two, namely "MILNET" for military purposes and the "ARPANET" new smaller for non-military purposes such as, universities. Combined both networks came to be known by the name of DARPA Internet, which then reduces to the Internet.

• Information

Many people use the terms Internet and World Wide Web, or just the Web, interchangeably, but the two terms are not synonymous. The World Wide Web is a global set of documents, images and other resources, logically interrelated by hyperlinks and referenced with Uniform Resource Identifiers (URIs). URIs allow providers to symbolically identify services and clients to locate and address web servers, file servers, and other databases that store documents and provide resources and access them using the Hypertext Transfer Protocol (HTTP), the primary carrier protocol of the Web. HTTP is only one of the hundreds of communication protocols used on the Internet. Web services may also use HTTP to allow software systems to communicate in order to share and exchange business logic and data.
World Wide Web browser software, such as Microsoft's Internet Explorer, Mozilla Firefox, Opera, Apple's Safari, and Google Chrome, let users navigate from one web page to another via hyperlinks embedded in the documents. These documents may also contain any combination of computer data, including graphics, sounds, text, video, multimedia and interactive content including games, office applications and scientific demonstrations. Through keyword-driven Internet research using search engines like Yahoo! and Google, users worldwide have easy, instant access to a vast and diverse amount of online information. Compared to printed encyclopedias and traditional libraries, the World Wide Web has enabled the decentralization of information.
The Web has also enabled individuals and organizations to publish ideas and information to a potentially large audience online at greatly reduced expense and time delay. Publishing a web page, a blog, or building a website involves little initial cost and many cost-free services are available. Publishing and maintaining large, professional web sites with attractive, diverse and up-to-date information is still a difficult and expensive proposition, however. Many individuals and some companies and groups use web logs or blogs, which are largely used as easily updatable online diaries. Some commercial organizations encourage staff to communicate advice in 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. Collections of personal web pages published by large service providers remain popular, and have become increasingly sophisticated. Whereas operations such as Angelfire and GeoCities have existed since the early days of the Web, newer offerings from, for example, Facebook and MySpace currently have large followings. These operations often brand themselves as social network services rather than simply as web page hosts.
Advertising on popular web pages can be lucrative, and e-commerce or the sale of products and services directly via the Web continues to grow. In the early days, web pages were usually created as sets of complete and isolated HTML text files stored on a web server. More recently, websites are more often created using content management or wiki software with, initially, very little content. Contributors to these systems, who may be paid staff, members of a club or other organization or members of the public, fill underlying databases with content using editing pages designed for that purpose, while casual visitors view and read this content in its final HTML form. There may or may not be editorial, approval and security systems built into the process of taking newly entered content and making it available to the target visitors.

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  Communication

E-mail is an important communications service available on the Internet. The concept of sending electronic text messages between parties in a way analogous to mailing letters or memos predates the creation of the Internet. Today it can be important to distinguish between internet and internal e-mail systems. Internet e-mail may travel and be stored unencrypted on many other networks and machines out of both the sender's and the recipient's control. During this time it is quite possible for the content to be read and even tampered with by third parties, if anyone considers it important enough. Purely internal or intranet mail systems, where the information never leaves the corporate or organization's network, are much more secure, although in any organization there will be IT and other personnel whose job may involve monitoring, and occasionally accessing, the e-mail of other employees not addressed to them. Pictures, documents and other files can be sent as e-mail attachments. E-mails can be cc-ed to multiple e-mail addresses.
Internet telephony is another common communications service made possible by the creation of the Internet. VoIP stands for Voice-over-Internet Protocol, referring to the protocol that underlies all Internet communication. The idea began in the early 1990s with walkie-talkie-like voice applications for personal computers. 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 voice traffic, VoIP can be free or cost much less than a traditional telephone call, especially over long distances and especially for those with always-on Internet connections such as cable or ADSL. VoIP is maturing into a competitive alternative to traditional telephone service. Interoperability between different providers has improved and the ability to call or receive a call from a traditional telephone is available. Simple, inexpensive VoIP network adapters are available that eliminate the need for a personal computer.
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 dialling and reliability. Currently, a few VoIP providers provide an emergency service, 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 phone equipment and the Internet access devices. VoIP has also become increasingly popular for gaming applications, as a form of communication between players. Popular VoIP clients for gaming include Ventrilo and Teamspeak. Wii, PlayStation 3, and Xbox 360 also offer VoIP chat features.

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  Data transfer

File sharing is an example of transferring large amounts of data across the Internet. A computer file can be e-mailed to customers, colleagues and friends as an attachment. It can be uploaded to a website 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 for access to the file. The price can be paid by the remote charging of funds from, for example, a credit card whose details are also passed—usually 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 worldwide basis, are changing the production, sale, and distribution of anything that can be reduced to a computer file for transmission. This includes all manner of print publications, software products, news, music, film, video, photography, graphics and the other arts. This in turn has caused seismic shifts in each of the existing industries that previously controlled the production and distribution of these products.
Streaming media refers to the act that many existing radio and television broadcasters promote Internet "feeds" of their live audio and video streams (for example, the BBC). They may also allow time-shift viewing or listening such as Preview, Classic Clips and Listen Again features. These providers have been joined by a range of pure Internet "broadcasters" who never had on-air licenses. This means that an Internet-connected device, such as a computer or something more specific, can be used to access on-line media in much the same way as was previously possible only with a television or radio receiver. The range of available types of content is much wider, from specialized technical webcasts to on-demand popular multimedia services. Podcasting is a variation on this theme, where—usually audio—material is downloaded and played back on a computer or shifted to a portable media player to be listened to on the move. These techniques using simple equipment allow anybody, with little censorship or licensing control, to broadcast audio-visual material worldwide.
Webcams can be seen as an even lower-budget extension of this phenomenon. While some webcams can give full-frame-rate video, the picture is usually either small or updates slowly. Internet users can watch animals around an African waterhole, ships in the Panama Canal, traffic at a local roundabout or monitor their own premises, live and in real time. Video chat rooms and video conferencing are also popular with many uses being found for personal webcams, with and without two-way sound. YouTube was founded on 15 February 2005 and is now the leading website for free streaming video with a vast number of users. It uses a flash-based web player to stream and show video files. Registered users may upload an unlimited amount of video and build their own personal profile. YouTube claims that its users watch hundreds of millions, and upload hundreds of thousands of videos daily.