HUB, SWITCH, ROUTER, BRIDGE

Hub
Alat penghubung atar komputer, semua jenis komunikasi hanya dilewatkan oleh hub. hub digunakan untuk sebuah bentuk jaringan yang sederhana (misal hanya untuk menyambungkan beberapa komputer di satu group IP lokal)
ketika ada satu paket yang masuk ke satu port di hub, maka akan tersalin ke port lainnya di hub yg sama dan semua komputer yg tersambung di hub yang sama dapat membaca paket tersebut. Cara kerja Hub pada dasarnya adalah sebuah pemisah sinyal (signal splitter). Ia mengambil bit-bit yang datang dari satu port dan mengirimkan copynya ke tiap-tiap port yang lain. Setiap host yang tersambung ke hub akan melihat paket ini tapi hanya host yang ditujukan saja yang akan memprosesnya. Ini dapat menyebabkan masalah network traffic karena
paket yang ditujukan ke satu host sebenarnya dikirimkan ke semua host (meskipun ia hanya diproses oleh salah satu yang ditujukannya saja).
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Switch
Sebuah alat yang menyaring/filter dan melewatkan(mengijinkan lewat) paket yang ada di sebuah LAN. switcher bekerja pada layer data link (layer 2) dan terkadang di Network Layer (layer 3) berdasarkan referensi OSI Layer Model. Biasanya switch banyak digunakan untuk jaringan LAN token star.
Dan switch ini digunakan sebagai repeater/penguat. Berfungsi untuk menghubungkan kabel-kabel UTP ( Kategori 5/5e ) komputer yang satu dengan komputer yang lain. Dalam switch biasanya terdapat routing, routing sendiri berfungsi untuk batu loncat untuk melakukan koneksi dengan komputer lain dalam LAN.
Switch adalah hub pintar yang mempunyai kemampuan untuk menentukan tujuan MAC address dari packet. Daripada melewatkan packet ke semua port, switch meneruskannya ke port dimana ia dialamatkan. Jadi, switch
dapat secara drastis mengurangi traffic network. Switch memelihara daftar MAC address yang dihubungkan ke port-portnya yang ia gunakan untuk menentukan kemana harus mengirimkan paketnya. Karena ia beroperasi pada MAC address bukan pada IP address, switch secara umum lebih cepat daripada sebuah router.

Router
Alat yang bertugas untuk mengantarkan paket data dalam jaringan. router dapat digunakan jika tersambung paling tidak dengan dua jaringan yang berbeda sehingga pengaturan tersebut membutuhkan sebuah router.Router berada di sisi gateway sebuah tempat dimana dua jaringan LAN atau lebih untuk disambungkan. Router menggunakan HEADERS dan daftar tabel pengantar (Forwarding Table) untuk menentukan posisi yang terbaik untuk mengantarkan sebuah paket jaringan dan juga menggunakan protokol seperti ICMP,HTTP untuk berkomunikasi dengan LAN lainnya dengan konfigurasi terbaik untuk jalur antar dua host manapun.

Bridge

Sesuai dengan namanya, alat ini dipergunakan untuk menjembatani 2 jaringan. Tetapi berbeda dengan repeater yang hanya berfungsi sebagai jembatan fisik, bridge dapat berfungsi juga sebagai jembatan nalar (logical) seperti pembongkaran dan penyusunan paket, penyelematan, buffering dan lain-lain. Dengan demikian bridge dapat dipakai untuk menghubungkan 2 macam jaringan yang berbeda format paketnya ataupun yang berbeda kecepatan transmisinya. Misal dua kantor menggunakan dua jenis sistem jaringan yang berbeda, yang satu menggunakan sistem ethernet dan yang lainnya menggunakan sistem Arcnet, maka kedua sistem tersebut dapat digabung dengan menggunakan bridge.

L A N

Local Area Network (LAN) adalah sejumlah komputer yang saling dihubungkan bersama di dalam satu areal tertentu yang tidak begitu luas, seperti di dalam satu kantor atau gedung. Secara garis besar terdapat dua tipe jaringan atau LAN, yaitu jaringan Peer to Peer dan jaringan Client-Server. Pada jaringan peer to peer, setiap komputer yang terhubung ke jaringan dapat bertindak baik sebagai client maupun server. Sedangkan pada jaringan Client-Server, hanya satu komputer yang bertugas sebagai server dan komputer lain berperan sebagai client.

Komponen hardware dan software penyusun LAN

1. Komponen Fisik:

a. Host / Workstation

Bisa berupa Personal Compuetr (PC) atau Laptop.

b. Network Interface Card (NIC)

Ada beberapa tipe NIC, yaitu ISA dan PCI. Salah satu jenis NIC adalah Ethernet Card, yang merupakan card yang dipasang di komputer untuk dapat berkomunikasi dengan komputer lainnya melalui jaringan LAN. Setiap Ethernet Card memiliki MAC Address (Medium Access Control) yang bersifat unik, artinya tidak ada 2 Ethernet Card yang memiliki MAC Address yang sama.

c. Kabel

Kabel yang biasa dipakai adalah kabel UTP.

d. Topologi jaringan

Ada 3 topologi utama yang dikenal di jaringan komputer:

1) Topologi Star

Masing-masing workstation dihubungkan secara langsung ke server atau hub. Keunggulannya adalah dengan adanya kabel tersendiri untuk setiap workstation ke server, maka bandwidth atau lebar jalur komunikasi dalam kabel akan semakin lebar sehingga akan meningkatkan unjuk kerja jaringan secara keseluruhan. Dan juga bila terdapat gangguan di suatu jalur kabel maka gangguan hanya akan terjadi dalam komunikasi antara workstation yang bersangkutan dengan server, jaringan secara keseluruhan tidak mengalami gangguan. Kelemahannya adalah kebutuhan kabel yang lebih besar dibandingkan dengan topologi lainnya.

2) Topologi Bus

Menggunakan sebuah kabel tunggal atau kabel pusat di mana seluruh workstation dan server dihubungkan. Keunggulannya adalah mudah dalam pengembangannya tanpa mengganggu workstation lain. Sedangkan kelemahannya adalah bila terdapat gangguan di sepanjang kabel pusat maka keseluruhan jaringan akan mengalami gangguan.

3) Topologi Ring

Semua workstation dan server dihubungkan sehingga terbentuk suatu pola lingkaran atau cincin. Tiap workstation ataupun server akan menerima dan melewatkan informasi dari satu komputer ke komputer lain, bila alamatalamat yang dimaksud sesuai maka informasi diterima dan bila tidak informasi akan dilewatkan. Kelemahan dari topologi ini adalah setiap node dalam jaringan akan selalu ikut serta mengelola informasi yang dilewatkan dalam jaringan, sehingga bila terdapat gangguan di suatu node maka seluruh jaringan akan terganggu. Sedangkan keunggulannya adalah tidak terjadinya collision atau tabrakan pengiriman data seperti pada topologi Bus, karena hanya satu node dapat mengirimkan data pada suatu saat.

2. Komponen Software:

a. Sistem Operasi Network

Sistem operasi network dibedakan menjadi dua berdasarkan tipe jaringannya, yaitu sistem jaringan Client-Server dan sistem jaringan Peer to peer.

b. Network Adapter Driver (NAD)

Setiap network card akan memiliki driver atau program yang berfungsi untuk mengaktifkan dan mengkonfigurasi network adapter tersebut disesuaikan dengan lingkungan dimana network card tersebut dipasang agar dapat digunakan untuk melakukan komunikasi data.

c. Protokol Jaringan

TCP/IP (Transmission Control Protocol/Internet Protocol), dengan protocol ini akan memungkinkan perbedaan dari jenis komputer dan sistem operasi tidak menjadi masalah yang berarti dalam berkomunikasi antar komputer.

Device Penghubung dalam LAN

Merupakan perangkat-perangkat yang digunakan untuk menghubungkan antara network satu dengan network yang lain dalam jaringan. Perangkat-perangkat penghubung dalam LAN secara umum, yaitu:

1. Repeater

Menerima sinyal dari satu segmen kabel LAN dan memancarkannya kembali dengan kekuatan yang sama dengan sinyal asli pada segmen kabel LAN yang lain.

2. Bridge

Mirip Repeater namun lebih cerdas, karena bridge mempelajari setiap alamat Ethernet yang terhubung dengannya. Umumnya Bridge digunakan untuk menghubungkan antar jaringan yang berbeda secara topologi/fisik.

3. Router

Memiliki kemampuan untuk melewatkan paket IP dari satu jaringan ke jaringan lain yang mungkin memiliki banyak jalur diantara keduanya. Umumnya Router digunakan untuk menghubungkan antar jaringan yang berbeda secara logic

OPERA 10 NEW TURBO

Opera 10: New Browser with Turbo Speed Opera has released the latest version of the browser Opera 10. Opera version 10 is claimed by the official vendor with the Opera browser with turbo speed. Indeed many new features coupled with increased planted some previous features make the Opera 10 browser is suitable for known turbo-speed browser. Opera 10 is equipped with a Opera Turbo Compression that will speed up while browsing with Internet connection is weak. Feature of this turbo Opera browsers could make this a speed two times faster when used with speed internet browsing is very slow (100 kbps). Opera Turbo feature you can set to start automatically when your internet speed is weak or fallen dramatically, so your browsing speed can be automatically maintained. This opera turbo features was useful when used in Hotspot area was busy or when using the internet connection with a slow speed as I use today. In addition to accelerating the process of browsing, Opera Turbo feature will also save your internet quota for using data compression method. Opera Turbo feature is able to compress the size of web pages up to 80% smaller. This will save your internet costs, especially for internet users with a quota limit (volume based). Opera Turbo feature is compatible with the all the website pages. The activated Opera Turbo features will not change the look and layout design of the website, but will only accelerate loading only. Opera Turbo will make flash content such as videos on Youtube and so only load when you click. Also Opera Turbo will compress and reduce the image size so that the web page will be much faster as accessible and cost effective. However you will still be able to see the image with maximum quality if you want. Simply right click the image you want and choose "Reload Image in Full Quality" then you will see these images with maximum quality. Opera 10 was using Presto 2.2 engine which has a speed of up to 40% faster when used in intensive active pages like Gmail and facebook. Features that make Opera great not forget the design and appearance of this new browser. Opera 10 is designed with an elegant new look of upscale designer, John Hicks. All the above features is still a small part of the new features in Opera 10 browser. There are still many other features are available and ready to use. To explore all the new features the following functions of each of these features, I will discuss in the next tutorial, entitled Optimization and Navigating The Opera 10 feature browser, just wait ..! Download Opera 10 | License: Free | Size: 8.66 Mb

Cold War Between Developer of The Best Internet Browser Anyone would want to surf with a fast and convenient. To be able to enjoy it, there are several factors that should we have. In addition to a good internet connection, it is necessary also the right browser. For that browsers that have a high speed have always been developed by various vendors. End year 2009 is a month of heavy competition for some browser developers. They in turn took the latest version of the browser of their seed, plant a variety of new features and extra capacity. For example, the issue Mozilla Firefox 3.5 is equipped with a patch for improved stability and security, which released the Google 3 Google Chrome with Javascript fast rendering technology and new Omnibox it, Microsoft is out of Internet Explorer 8 with a high level of security, Opera is also not to be outdone the browser Opera 10 is equipped with a Turbo Speed. Even one of Microsoft's rivals, Apple also has a flagship browser for Windows that Safari 4 is called - described as the fastest browser today. War of technology, design and features continue to be developed by the browser developers to increase excellence and patching the browser weaknesses, as if not to be outdone by its competitor's browser developers work. But this competition is always a bit much to our benefit as a user. With the existing technology of war and growing, so we are always treated with high-tech browser that almost everything that we can enjoy for free. When developers fight and fight for dominance of technology in the online world, we can take advantage and choose which browser best with our needs. I personally use the Google browser Chrome as my current favorite. But some new features of Opera 10, especially data compression feature that can reach 80% had made me want to move. Each browser has its own advantages and disadvantages. the next opportunity, I will discuss the advantages and disadvantages of the browser - the browser is in more detail. I will compare the frontal each technology and the features carried by each - their existing browser. Browser war was about to begin.

Dementia Diseases and Solutions Problem turns on a person's life so much stress that damage the health of their memory. No wonder many people today talk about a disease that most dreaded memories of dementia. Indicators of clinical syndrome characterized by a variety of disorders of cognitive functions but without disturbance of consciousness followed. You know that it is the cognitive process of thinking how a person's ability, is closely related to the performance of the human brain. Try to imagine what if cognitive/ability of the brain to think you offended? To overcome these problems the main thing is understanding dementia. That's the first thing most important. Actually, not only economic problems, debt, or burden of life but also environmental factors that can affect the psyche of behavior change is more irritable and brutal or worse someone could be mad because the disease is dementia. I mean the environment is a workplace that is too heavy, less rest, more energy for thinking and physical activity but not comparable to the input of nutrients enough food for your brain and body. I'll try to explain important matters and the handling of issues regarding dementia recommended. What is the main cause of dementia diseases? Causes of dementia are the most common head injury, alcohol-related dimentia and associated with movement disorders, for example Hutington disease and Parkinson's disease. For that you can see in detail about this issue on the official site www.dementiaguide.com dementia symptoms are: Memory disorders such as forgetting a phone number, conversation, and the events that day. Disruption orientation example: a person with dementia may forget how to back to his room after going to the bathroom. Language disorders such as difficulty to name things, talk is not clear and rather round and round. Changes in behavior, it is dangerous to others because patients with dementia were also seen less memperhatkan effects of their behavior toward others. They generally become paranoid and hostile to family members or caregivers. Belonging to severe personality changes and easily visible anger. Psychosis is associated with imagination, a hallucination and the tendency of physical aggression. How? Apparently this disease is very dangerous dementia. dementia treatment you need to do from now on as well. Now progress is very good medicine, medical diagnosis from the medical and psychiatric experts can be done quickly through the psychic and psychological approaches. Official website of dementia is one solution you can begin to do and is recommended especially to protect and heal the people you love.

BROWSER

Mozilla Released Patch to Fix 10 bugs Mozilla Firefox 3.5 Yesterday Mozilla has released updates and patches for Firefox version 3.5 is known to have 10 weaknesses. 10 bugs consists of problems in the rendering code javascript, some problems in the browser applications, and the emergence of security holes that could be in exploitation by hackers. 7 out of 10 Firefox bugs found in version 3.5 by the mozilla developer team is the engine of a browser crash when doing trace javascript. This is possible because the memory is corrupt. Developer mozilla recommend that users disable or enable javascript non if they do not or have not updated the patch or the latest version of mozilla. 3 other bugs found in Firefox version 3.5 is in the function's RSS firefox, Mozilla XML - based language, XUL (XML User Interface Language) which is used to create web applications can operating offline, and there are security gaps in the URL-spoofing. Reportedly doing mozilla firefox development for version 3.6. Development is done specifically so that firefox can detect some of the outdated plugins automatically, such as Apple Quick Time, Adobe Flash, Shockwave and Reader, Microsoft Silverlight and also Sun Java. Reportedly the latest version of Firefox will be completed and released around November of this year. But for those of you Mozilla Firefox 3.5 users who have not updated, please update your firefox to the latest and safest version of the current which has been equipped with the latest patch, which is mozilla firefox 3.5.3. Click here to download and update Mozilla Firefox version 3.5.3

Google Develops New Product : Fast Flip Internet giant Google is developing a new product called FAST FLIP. Fast Flip was developed by Google to facilitate and accelerate the search for articles and news online on the web. Fast Flip in online yesterday by google labs site where Fast Flip is still in prototype form and will be developed further by google. Flip Fast Online yesterday it was probably an online experiment by google. Please click to see the prototype Fast Fold. (Fast Flip can go online and disappear at any time because there is still a prototype experiment google). Fast Flip allows users to see thumbnails news sites so you can find the latest news direct these sites as thumbnails without having to open it fully. This is of course easier for you to explore the news because you don't need to open a web page that doesn't match your search. Google Fast Flip is claimed will be able to increase interest visitors to read a site and will be able to increase earnings from these sites. Fast Flip shows news sites are like a magazine, which when you select one of the news sites, it will be displayed in the form of images such as magazine pages. Fast Flip currently still under development and further research. Fast Flip will also adopt the technology for the iPhone touch screen so that later you can see news from online sites like reading a magazine, whether it's from your PC or from your iPhone. Sometime Google Fast Flip will be officially released. Google party still developing ideas and concepts of this Fast Flip. Besides a new breakthrough, Fast Flip is also made by google to create a publisher can earn more revenue from articles or news they publish.

Google Chrome 3 Released Today has released Google Chrome 3. Google Chrome 3 is the latest version of google chrome with a fixed forward speed of page loading high. Even google chrome 3 is claimed by google javascript capable rendered by an increase up to 25% from the previous version. Various improvements and repairs have been made by Google to further refine and improve the performance of these browsers. Repairs carried out on some features, such as increased tabs, video and audio. New features have also been invested in the latest version of Google Chrome, such as customizable tab which allows you to set the thumbnail of your favorite pages.Google also uses Omnibox, the web search bar and address bar and via the icon that will facilitate you in browsing the internet. Google chrome also has support HTML5 video tag that will make video look more smooth and reduce the use of plugins. Display Google Chrome 3 Indeed this week was a busy week for Google, which Google released the latest version of the Google Chrome 3 browser, conducting new product development for Google Fast Flip, and various research and other new development. Applause for Google. Download Google Chrome 3 | License: Free

Safari 4: Browser quickly with 3D look Who is not familiar with Apple, a Mac OS developer company which is a heavy competition from Microsoft. As one of the Internet giant, Apple is also not to be outdone by other developers who are vying issued high-tech browser. Apple also released its flagship browser is Safari. Safari 4 is the output of Apple's latest browser now available also in versions of Windows. Like Chrome 3 and Opera 10, Safari 4 is also focused its technology on the speed of loading a web page. But there is one advantage that is not owned by another competitor, namely 3 dimensional view. Safari 4 give the appearance of 3 dimension in a variety of features such as on Top Site, History and bookmarks. At the Top Site, you can see the thumbnail websites you visit frequently. Website in Top Site you can also set it manually. In the bookmarks and history, you can see thumbnails of each web site in your bookmarks and view your site ever visited. 3D display for this history and bookmarks, including new and has never been done by other browsers. 3D Display for Safari Tops Site 4 3D Display to Bookmark and History With the appearance of 3 dimension so elegant, do not forget the safari 4 initial orientation to the browser to load web pages faster. Safari 4 competing with Opera and Google Chrome in the speed issue, but had no competition in the display problems. For features and optimization tips Safari 4 in greater detail and depth, I'll post the next tutorial. Download Browser Safari 4 | License: Free

PICASA

Picasa 3.5: New Version Photo Editing Software from Google

Google has updated picassa be Picasa 3.5. Picasa is a free software google outputs that allow you to edit and organize your images or photographs, as well as to synchronize and share your images and photographs are on Picassa Web Albums, photo sharing site owned by Google.

Picasa 3.5 now has added features with name tags on the latest technology available in Picassa Web Albums is Power Name Tags. With name tags this feature, then you can organize your images and photos on any tag you want.

Picasa 3.5 also has a Geotag feature where you can give geotagged using Google Maps with ease. Process import photos from digital camera and upload it to Picassa Web Albums also become faster and requires only one step.

With this newest version of Picasa, you can:

1. Organize and edit pictures on your hard drive easily. You can also import images from your digital camera quickly.
2. You can share your images with the upload in Picasa Web Albums by selecting the file and click Upload.
3. Provide name tags on your images by using Picasa 3.5 or directly through Picasa Web Albums.

Alloy between Picasa 3.5 and Picassa Web Albums will give you the facility setting, image organization, editing, and share photos easily and of course .. Free!!

Download Google Picasa 3.5 | License: Free | Size: 9.2 Mb | Operating System: Windows XP/VISTA/7

History of Google: From Garage to a Worldwide

Posted: 03 Oct 2009 05:08 AM PDT

Today who does not know Google? Internet giant this one gradually grown in popularity in the world of the Internet and the more distant left competitors. With approximately 20,000 full time workers now, Google is always out of innovation and new products are becoming more and more difficult unrivaled by its competitors.

Currently Google is the big companies in America with revenues of approximately $21 billion in the year 2008 and is targeted to reach $40 billion in the year 2009. Earnings of 99.9% was obtained from the advertising spread in almost all aspects of the virtual world. Google's initial mission is to "bring together all the information from all over the world and make it accessible and useful" this is now indeed become a "star" in the world of the Internet.

Google (Larry Page and Sergey Brin) in Garage 1998

All of Google hardware from its Stanford days (1998) where it was initially called backrub. Google now operates over 250,000 Linux servers of its own design.

Google Beta in the year 1998

But who would have thought the internet giant and the star came from the garage of a friend's two boys and began in January 1996. At that time a study conducted by Larry Page and worked with Sergey Brin when they were both PhD students at Stanford University, California. They concluded that the search engine that analyzed the relationships between websites produce better grades than the search engines with the existing methods at that time.

Finally they both make a search engine with the name "BackRub" because it has a system to check backlinks to estimate whether a site is important. At that moment a small op named Rankdex also doing the same investigation.

Based on the logic that the page with many links pointing to that page is a page that's important and relevant, then Larry Page and Sergey Brin do testing and make their thesis research to their search engines. Finally, they made search engine used by Stanford University in google.stanford.edu. And the domain google.com was registered on 15 September 1997 and became company Google Inc.

On September 4, 1998, Google is at that time was still based at the garage owned by a friend of Larry Page and Sergey Brin already reached investment to $1.1 million, including $100,000 from Andy Bechtolsheim, one of the inventors of Sun Microsystems. Google's new office move in March 1999 to Palo Alto. Since then Google continues to grow and continue to get lots of visits to search for enginenya simple design and good search results.

First Google owned servers

In 2000 Google began to open kahirnya advertising channels based on keywords, which is Google Adwords. On 4 September 2001 Google has also patented a system of ranking search results that is currently popular is called PageRank. Google's continued success skyrocketed with the growing number of innovations and services that benefit Internet users. It could make a lot of other Internet giants like Yahoo, Microsoft and even became worried. Even until now even Google will continue to innovate with the launch of new products such as the Google Flip, and is always updating and developing products such as the length of Picasa and Google Chrome. Even Google is also diligently perfecting and completing various product features such as Google Translate widget can now be installed on all site pages.

Google's own name is actually the alias of the word Googol, which means 10 rank 100, which means the numbers 1 and followed by one hundred zeros that are meant to show that on Google there are lots of information that almost "innumerable".