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Fundamentals of Computer Networks

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Fcn assignment

  1. 1. 1 CE51100-1 - Fundamentals of Computer Networks 2010 Introduction Network:Is a computer network, mostly get back or referred as a network, it contain a lot of computers, devices connect together through a channels that simplification the connection between the users, and allow to share data or information with users. Networks may be classified according to a wide variety of characteristics. 1.0-Type of Networks:-Local-area networks (LANs): The computers are geographically close together (that is, in the same building).A computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. A system of LANs connected in this way is called a wide-area network (WAN). Most LANs connect workstations and personal computers. Each node (individual computer) in a LAN has its own CPU with which it executes programs, but it also is able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as data. Users can also use the LAN to communicate with each other, by sending e-mail or engaging in chat sessions. Local-area networks (LANs) 1 CE51100-1 - Fundamentals of Computer Networks 2010
  2. 2. 2 CE51100-1 - Fundamentals of Computer Networks 2010 -Wide-area networks (WANs): The computers are farther apart and are connected by telephone lines or radio waves. A computer network that spans a relatively large geographical area. Typically, a WAN consists of two or more local-area networks (LANs). Computers connected to a wide-area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet. Wide-area networks (WANs) 2 CE51100-1 - Fundamentals of Computer Networks 2010
  3. 3. 3 CE51100-1 - Fundamentals of Computer Networks 2010 -Campus-area networks (CANs): The computers are within a limited geographic area, such as a campus or military base. Acronym for campus-area network. An interconnection of local-area networks within a limited geographical space, such as a school campus or a military base. Campusarea networks (CANs) 3 CE51100-1 - Fundamentals of Computer Networks 2010
  4. 4. 4 CE51100-1 - Fundamentals of Computer Networks 2010 -Metropolitan-area networks (MANs): A data network designed for a town or city. Short for Metropolitan Area Network, a data network designed for a town or city. In terms of geographic breadth, MANs are larger than local-area networks (LANs), but smaller than wide-area networks (WANs). MANs are usually characterized by very highspeed connections using fiber optical cable or other digital media. Metropolitanarea networks (MANs) 4 CE51100-1 - Fundamentals of Computer Networks 2010
  5. 5. 5 CE51100-1 - Fundamentals of Computer Networks 2010 -Home-area networks (HANs): A network contained within a user's home that connects a person's digital devices. Short for home area network. A HAN is a network contained within a user's home that connects a person's digital devices, from multiple computers and their peripheral devices to telephones, VCRs, televisions, video games, home security systems, "smart" appliances, fax machines and other digital devices that are wired into the network. Home-area networks (HANs) 5 CE51100-1 - Fundamentals of Computer Networks 2010
  6. 6. 6 CE51100-1 - Fundamentals of Computer Networks 2010 Requirements: 2.0-Technology Involved:-Definition and usage: The phrase technology derive from a Latina word is originally contain 2 words the first word is techno (that’s mean ART or ACCOPATION), second the LOGY (which mean STUDY or SCIENCE). Hence the expression of Technology mean’s or applies for Scientific and knowledge in every field. There are two reasons to follow scientific knowledge: for the sake of the knowledge itself and for the practical uses of that knowledge. Because this second aspect of science affects the lives of most people, it is more familiar than the first. Knowledge must be gained, however, before it can be applied, and often the most important technological advances arise from research pursued for its own sake. 6 CE51100-1 - Fundamentals of Computer Networks 2010
  7. 7. 7 CE51100-1 - Fundamentals of Computer Networks 2010 Traditionally, new technology has been concerned with the construction of machines, structures, and tools on a relatively large scale. The development of materials for building bridges or skyscrapers is an example of this, as is the development of the internalcombustion engine and the nuclear reactor. While such activities involve all the sciences, from chemistry to nuclear physics, the overriding goal has been the same: to improve the human condition by finding better ways to deal with the macroscopic world. Since World War II, the focus of technological activity has undergone a major change. While the old activities are still pursued, they have been largely superseded by applications of technology at the microscopic level. Instead of building large-scale structures and machines, modern-day technology tends to concentrate on finding improved ways to transfer information and to develop new materials by studying the way atom s come together. The silicon chip and microelectronics typify this new technological trend, as does the blossoming of genetic engineering. The trend can be expected to continue into the foreseeable future. 7 CE51100-1 - Fundamentals of Computer Networks 2010
  8. 8. 8 CE51100-1 - Fundamentals of Computer Networks 2010 The dividing line between what we include in the following list as technology and what we call science elsewhere in this volume is somewhat arbitrary. In general, what we have done is this: if a term is essential to understanding a particular branch of science, it appears in the list for that science. Thus, atom appears with the physical sciences, even though an understanding of atoms is clearly important to the new technology. If, however, the term involves something that is likely to affect an individual's life, even though it is not a central concept of a particular branch of science, it is listed under “Technology.” The words in the following section have been chosen because they are likely to appear without explanation in many publications, particularly in articles and books dealing with the impact and implications of technology. This section does not emphasize the social consequences of new technology, but concentrates instead on the basic knowledge needed to understand how technology works. 3.0-Methods of high Internet Connection:(Cable, DSL, Satellite & Wireless Internet connection) -Wireless: With recent advances in wireless Internet technology, high speed wireless connections are now readily available on laptops, cell phones, and other mobile computing devices. Some emerging forms of wireless technology, such as EV-DO and WiMax, are starting to turn wireless connectivity into the dominant form of broadband Internet access. Whether you need a wireless local area network for your home or small office, or wireless Internet access on your laptop while sitting in your favorite coffee shop, there are a growing number of wireless ISPs that can provide you with such service -- and at speeds comparable to residential DSL and Cable. -Wireless Is Becoming Incredibly Fast: One new wireless technology in development as of early 2009 is poised to increase the download speeds of wireless even further. WiMax promises to deliver maximum speeds 8 CE51100-1 - Fundamentals of Computer Networks 2010
  9. 9. 9 CE51100-1 - Fundamentals of Computer Networks 2010 of up to 7 Mbps -- to your laptop, your car, your cell phone, and your home. WiMax is only just now becoming available in some U.S. cities, but expect to see it in more locations by the end of the year and throughout 2010. This increase in speed means that you no longer have to limit your mobile computing activities to basic email and text messaging. When you use a high speed wireless Internet service provider, you can download streaming media and other large file formats just as easily as you could with the broadband Internet connection in your home or at the office. Nearly every laptop sold today already has a wireless adapter installed in it, plus there are many new handheld devices that are set up for remote Internet access. The number of hotspots that the major wireless ISPs have in operation is also constantly increasing. So, if you like or need to have access to the Internet while on the go, then slow download speeds and limited availability simply no longer serve as obstacles. -The First High Internet Connection (Cable): When you connect to the Internet, you might connect through a regular modem, through a local-area network connection in your office, through a cable modem or through a digital subscriber line (DSL) connection. DSL is a very high-speed connection that uses the same wires as a regular telephone line. 9 CE51100-1 - Fundamentals of Computer Networks 2010
  10. 10. 10 CE51100-1 - Fundamentals of Computer Networks 2010 Here are some advantages of DSL: * You can leave your Internet connection open and still use the phone line for voice calls. * The speed is much higher than a regular modem * DSL doesn't necessarily require new wiring; it can use the phone line you already have. * The company that offers DSL will usually provide the modem as part of the installation. But there are disadvantages: * A DSL connection works better when you are closer to the provider's central office. The farther away you get from the central office, the weaker the signal becomes. * The connection is faster for receiving data than it is for sending data over the Internet. * The service is not available everywhere. In this article, we explain how a DSL connection manages to squeeze more information through a standard phone line -- and lets you make regular telephone calls even when you're online. - DSL: Stands for "Digital Subscriber Line." It is medium for transferring data over regular phone lines and can be used to connect to the Internet. However, like a cable modem, a DSL circuit is much faster than a regular phone connection, even though the wires it uses are copper like a typical phone line. An asymmetric DSL (ADSL) connection allows download speeds of up to about 1.5 megabits (not megabytes) per second, and upload speeds of 128 kilobits per second. That is why it is called ADSL and not just DSL (because of the asymmetric speeds). There is 10 CE51100-1 - Fundamentals of Computer Networks 2010
  11. 11. 11 CE51100-1 - Fundamentals of Computer Networks 2010 also a "Symmetric Digital Subscriber Line" (SDSL) which is similar to ADSL, but allows data transfer speeds of 384 Kilobits per second in both directions. Theoretically, this type of connection allows download speeds of up to 9 megabits per second and upload speeds of up to 640 kilobits per second. The difficult part in establishing an DSL circuit is that it must be configured to connect two specific locations, unlike a regular phone line or cable modem. DSL is often seen as the new, better alternative to the older ISDN standard. -Type of DSL: ADSL: Stands for "Asymmetric Digital Subscriber Line." ADSL is a type of DSL, which is a method of transferring data over copper telephone lines. While symmetrical DSL (SDSL) uploads and downloads data at the same speed, ADSL has different maximum data transfer rates for uploading and downloading data. For example, an ADSL connection may allow download rates of 1.5Mbps, while upload speeds may only reach 256Kbps. Since most users download much more data than they upload, this difference usually does not make a noticeable impact on Internet access speeds. However, for Web servers or other computers that send a lot of data upstream, ADSL would be an inefficient choice. 11 CE51100-1 - Fundamentals of Computer Networks 2010
  12. 12. 12 CE51100-1 - Fundamentals of Computer Networks 2010 -How does satellite Internet operate? How do you access the Internet other than dial-up if you live too far from a phone company office for DSL and there is no cable TV on your street? Satellite Internet access may be worth considering. It's ideal for rural Internet users who want broadband access. Satellite Internet does not use telephone lines or cable systems, but instead uses a satellite dish for two-way (upload and download) data communications. Upload speed is about one-tenth of the 500 kbps download speed. Cable and DSL have higher download speeds, but satellite systems are about 10 times faster than a normal modem. 12 CE51100-1 - Fundamentals of Computer Networks 2010
  13. 13. 13 CE51100-1 - Fundamentals of Computer Networks 2010 4.0-The companies that afford internet connection:For the companies that offer to the customers the internet line, they are many but the best one which I feel good about it is (TM net) provide a various internet connection to the customers and depend of how fast did the customer want or need and the price that is reasonable to you. And you can register easy because you will found their clients in everywhere and kind with you, besides they will explain every single thing that you might use or been useful for you and ofcourse to make their business get done. And here is the whole various connection of the company that is called (Streamyx) Package Combo Price Standard Price Saving Features (RM) +Rental (RM) (RM) 384 Kbps 60 45 + 25 = 70 10 With Modem 512 Kbps 90 77 + 25 = 102 12 Unlimited Access Lifetime Warranty 1 Mbps 110 99 + 25 = 124 14 1 E-mail 2 Mbps 140 188 + 25 = 213 73 Dynamic IP 4 Mbps 160 268 + 25 = 293 133 www.tmbroadband.com 5.0-Importance of Wi-Fi technology:- 13 CE51100-1 - Fundamentals of Computer Networks 2010
  14. 14. 14 CE51100-1 - Fundamentals of Computer Networks • 2010 WIFI gives you an extremely large amount of freedom because you can basically use it from anywhere. From your couch to your local shopping mall, wireless reliability can always lend a helping hand. Also, WIFI is not restricted to certain groups. No matter who you are, you can use it. And, on top of its convenience, WIFI is fast, reliable, and easy to use. In the corporate enterprise, wireless LANs are usually implemented as the final link between the existing wired network and a group of client’s computers. This gives these users wireless access to the full resources and services of the corporate network across a building or campus setting. • Wireless Fidelity is important to the wireless LAN world, because it is securely tested to assure ability of equipment of the same frequency band and feature. • WIFI is the certification logo given by the WIFI Alliance for equipments that passes the tests for compatibility for IEEE 802.11 standards. The WIFI Alliance organization, is a nonprofit organization that promotes the acceptance of 802.11 wireless technology and they ensures all WIFI certified 802.11 based wireless networking equipments works with all other WIFI certified equipments of the same frequency. The WIFI Alliance works with technical-groups like the IEEE and other companies that are developing new wireless networking equipments. 6.0-How Technology can affect human and life social? -The bright side of Wi-Fi Technology: • Technology with its rapid growing speed is influencing old ways of doing daily affairs. We don't need any more to move around to handle different tasks and chores since all of them will be done in a matter of pushing a button located on a remote control. • Nobody can deny that technology has brought comfort to our lives, but almost all of us confess this fact that technology by itself has got a lot of deficits that in long term will cause a lot of side effects either physically or emotionally. This is a fact that through the multi-media and the wide spread range of webs ( Internet) the 14 CE51100-1 - Fundamentals of Computer Networks 2010
  15. 15. 15 CE51100-1 - Fundamentals of Computer Networks 2010 concept of time and distance have been vanished and people can keep in touch with each other by means of such facilities. The negative view is the fact that they keep in touch in a virtual world not natural. Via the webs and mail the emotional feelings and thoughts can’t be transferred. People can convey their attitudes and thoughts much more effectively when they are close to each other. -The bad side of Wi-Fi Technology: • One bad effect of technology on life is that with more technology placing barriers between people, face to face meetings happen less. • This small, simple change leads to a whole host of very serious problems with society in general. People are becoming more lazy; choosing to stay at home and play video games than go to a basketball game or get together with friends. • On top of that, the new barriers that are made because of technology gives those who are most effected by them a decaying sense of pride in their country. In fact, it is this lack of pride that has spurred many of the anti-American feelings that are felt and publicized by people of this very country. • Not all technology is bad or evil, but we do need to be careful that we don't become slaves (meaning obsessed with, not actual slaves) to our own creations. Newspapers and local agencies and music stores have been forced to shut down since items are available online. 6.0-Criteria Requirements of Wi-Fi Technology:-Scope: • The term Wi-Fi was used for 802.11b only in the beginning, But today applies to the 802.11 substandard. • Certifying and owning the Trademark: The Wi-Fi Alliance, http://www.wi-fi.org/ • Standard frequency gross data rate modulation 15 CE51100-1 - Fundamentals of Computer Networks 2010
  16. 16. 16 CE51100-1 - Fundamentals of Computer Networks • 802.11a 5._ GHz 54 Mbps OFDM • 802.11b • 2010 802.11g 2.4 GHz 54 Mbps OFDM, PBCC 2.4 GHz 11 Mbps DSSS -Criteria: • How to choose the right standard – what area a, b and g good for? • 802.11b oldest, robust, good for indoors and outdoors, cheapest • 802.11g same frequency as 802.11b, higher bandwidth, BUT, because of • ODFM, a lot less robust for outdoor long haul links! For this, it is not a good choice! • 802.11a because of higher frequency, it does not go through obstacles as well. But, it makes for excellent high bandwidth long haul links, When LOS is given. • Indoors, it suffers from LOS problems. -How to choose standards and products: • As always: your requirements – what do you want to do? • Budget & availability • Especially for wireless gear: consider price development! • Don’t buy for 500 today, what next year might cost 100. • Legal considerations: • What is legally & practically :) possible where you are? • Where applicable: support/drivers for your Operating system? • Environmental specs: temperature! Humidity! • Power consumption -Types of Wi-Fi hardware: • Access Point (Includes Access Points, Residential Gateways, DSL & Cable Products) 16 CE51100-1 - Fundamentals of Computer Networks 2010
  17. 17. 17 CE51100-1 - Fundamentals of Computer Networks • 2010 Cellular Convergence (Products that enable both Wi-Fi and cellular communications) • Compact Flash • Embedded Client (Includes Notebooks, etc.) • Ethernet Client Device (Includes Wireless-to-Ethernet Station Adapters & Converters) • External Card (Includes PC Cards, PCMCIA Cards, Card Bus & SD Cards) • Internal Card (Includes Mini PCI Cards & PCI Cards) • PDAs • USB Client Device (Includes Dongles & Adapters) • Wireless Printers and Print Servers This was the list of types as used by the expert However, the line between types of hardware is not a strict one. Especially when you build and modify yourself, it makes sense to think of it as radio + chipset + surrounding hardware + software + all the externals (antennas, power supply ...) Types of usage change over time and may be hard to classify, e.g. point to point links, bridges, repeaters, mesh nodes (where the line between client and AP/server disappears). 17 CE51100-1 - Fundamentals of Computer Networks 2010
  18. 18. 18 CE51100-1 - Fundamentals of Computer Networks Anatomy of an AP/router WAN or Internet port Power supply Antenna Connection 2010 LAN ports Reset button Pigtail Chipset Broadcom Radio card 18 CE51100-1 - Fundamentals of ComputerUnused connectors Networks (Sometimes) 2010
  19. 19. 19 CE51100-1 - Fundamentals of Computer Networks 2010 -Features: output and sensitivity: • Examples for output power and receive sensitivity info Receive Sensitivity 1. -94dBm at 1 Mbps; 2. -88dBm at 2 Mbps; 3. -87 dBm at 5.5 Mbps; 4. -84dBm at 11 Mbps 5. Output Power (at the N connector) 6. +17.5dBm (max) to 7. +11.5dBm (min) 19 CE51100-1 - Fundamentals of Computer Networks 2010
  20. 20. 20 CE51100-1 - Fundamentals of Computer Networks 2010 -Some Products: The following examples of wireless hardware focus mostly on infrastructure related hardware, i.e. access points, gateways, bridges, point-to-point links rather than pure client cards. These examples are of course just a personal pick -based on an overview of many international projects. Alvarion/ Breezecom There are many many more vendors – to name a few we have omitted here: Cisco, 3COM, Gemtek, Tranzeo, Intel, Alvarion/Breezecom Pricing info in this presentation is meant as a very rough first orientation – prices change fast and are extremely dependent on quantity.Local availability, pricing and skills easily can be the most important buying points.(Antennas are subject of a separate presentation later in this course, and not being covered here). 20 CE51100-1 - Fundamentals of Computer Networks 2010
  21. 21. 21 CE51100-1 - Fundamentals of Computer Networks 2010 -Some Products: PC client cards: Many vendors. Older cards for 802.11b, g/b – newer cards are typically a/b/g and based on Atheros chipset.Sometimes with antenna connectors. Radio quality (output, sensitivity) varies a lot! Vendors worth looking at: Avaya (ex Orinoco) (old b cards!) Senao (200 mW cards, ext. ant.) Linksys,D-Link Home user equipment that can do many things more, as proven in many projects around the world. Hard to beat in price /performance. Some of their gear runs on GPLed Linux firmware, e.g. the Linksys WRT54G (b+g standards), for which a growing number of Firmware hacks exist, including mesh implementations. Comparable vendors in the low price range: e.g. D-Link, Net gear. Good entry points for WRT54G info: 21 CE51100-1 - Fundamentals of Computer Networks 2010
  22. 22. 22 CE51100-1 - Fundamentals of Computer Networks 2010 http://www.talug.org/events/20050115/Wireless_Linux/WRT54G_firmware.html http://www.seattlewireless.net/index.cgi/LinksysWrt54g -Some Products: Mikrotik: From Latvia, this company makes 2.4/5 Ghz routers, boards and WISP oriented software. Very interesting multi-radio (a/b/g) configurations. 1600 rm (check list!) for single AP, 3200 rm for a link Www http://www.mikrotik.com 22 CE51100-1 - Fundamentals of Computer Networks 2010
  23. 23. 23 CE51100-1 - Fundamentals of Computer Networks 2010 -Some Products: Smart bridges: Very good series of point to (multi)point links (airhaul), APs (airpoint), clients. Good global distribution, track record of rural deployments, incl. Mt. Everest.Rated 40 ... +65 Celsius! AP from 650 rm, Links from 1300 rm Www http://www.smartbridges.com -Some Products: Motorola Canopy: 23 CE51100-1 - Fundamentals of Computer Networks 2010
  24. 24. 24 CE51100-1 - Fundamentals of Computer Networks 2010 Products in (900 MHz), 2.4 GHz and 5 GHz bands. Focus on WISP, carriers, enterprise. Point to point and multipoint links. Proprietary (non-802.11) modulation very robust. 1300 to 1600 rm per end),( 500 rm for reflector) -Some Products: 4G Access cube: The 4G access cube is a little 2-4 radios Linux mesh box. * Dimensions: small (7x5x7cm) cube * Waterproof outdoor casing * No moving parts * Low power consumption (ca. 4W) * Power over Ethernet (802.3af standard) * Up to 4 WLAN (802.11a/b/g) interfaces * 400MHz MIPS processor AMD Au1500 aka Alchemy * 32MB flash * 64MB RAM * USB host, USB device 870 rm (2 radios) 24 CE51100-1 - Fundamentals of Computer Networks 2010
  25. 25. 25 CE51100-1 - Fundamentals of Computer Networks 2010 Www http://meshcube.org http://4g-systems.biz -WI-Fi Software: -WI-Fi Software Tools for Multiple Platforms Aircrack-ng is a WEP and WPA-PSK key cracking program for use on 802.11 networks. The primary purpose for the program is to recover a lost or unknown key once enough data is captured. Aircrack-ng has the following advantages over the original Aircrack release: • Updated and better documentation • Updated drivers, including new drivers not originally supported in Aircrack • New and faster WEP attack algorithm PTW • Supports Unix, Windows, and Zaurus • Includes fragmentation in attacks • Better cracking performance • Dictionary support for WEP attacks • Use multiple cards to capture simultaneously • New tools including airtun-ng, packetforge-ng (improved arpforge), wesside-ng (still under development), and airserv-ng(still under development) • Code optimizations and bug fixes -Wi-Fi Software Tools for Windows: 25 CE51100-1 - Fundamentals of Computer Networks 2010
  26. 26. 26 CE51100-1 - Fundamentals of Computer Networks 2010 KNSGEM II KNSGEM II is a program that takes the survey logs produced by NetStumbler, Kismet, or WiFiHopper and compiles the data with data Google earth to provide colorized 3D coverage maps. Nets tumbler Nets tumbler is a Wi-Fi tool for Windows that allows you to detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g. It has many uses: • Verify that your network is set up the way you intended. • Find locations with poor coverage in your WLAN. • Detect other networks that may be causing interference on your network. • Detect unauthorized "rogue" access points in your workplace. • Help aim directional antennas for long-haul WLAN links. • Use it recreationally for War Driving. Omni Peek Omni peek is the next generation version of commercial wireless analysis software from wild packets which combines the legacy applications AiroPeek and Ether Peek. Features of Omni Peek include the ability to: • Analyze any network interface, including 10Gigabit, Gigabit, and WAN adapters • Analyze media and data traffic simultaneously • View results in normal document formats such as PDF, HTML or just through email or IM clients 26 CE51100-1 - Fundamentals of Computer Networks 2010
  27. 27. 27 CE51100-1 - Fundamentals of Computer Networks • 2010 View high level details of traffic in a dashboard, or drill down into the individual packet payloads • View local, remote, or previously stored captures, including view multiple active captures at once. • View capture details by conversation pairs to quickly identify useful or problematic events • Change capture filters at will without restarting the capture sequence Stumbverter StumbVerter is a standalone application which allows you to import Network Stumbler's summary files into Microsoft's MapPoint 2004 maps. The logged WAPs will be shown with small icons, their color and shape relating to WEP mode and signal strength. As the AP icons are created as MapPoint pushpins, the balloons contain other information, such as MAC address, signal strength, mode, etc. This balloon can also be used to write down useful information about the AP. Lucent/Orinoco Registry Encryption/Decryption Lucent Orinoco Client Manager stores WEP keys in the Windows registry under a certain encryption/obfuscation. This Wi-Fi tool can be used to encrypt WEP keys into a registry value or to decrypt registry values into WEP keys. Wi-Fi Hopper Wi-Fi Hopper is a windows network discovery and connection client. Wi-Fi Hopper can assist auditors with Site Surveys, Connection parameter testing, and Network Discovery. Filters allow you to easily limit the details displayed, as well as what kinds and configurations of equipment will be tested. 27 CE51100-1 - Fundamentals of Computer Networks 2010
  28. 28. 28 CE51100-1 - Fundamentals of Computer Networks 2010 APTools APTools is a utility that queries ARP Tables and Content-Addressable Memory (CAM) for MAC Address ranges associated with 802.11b Access Points. It will also utilize Cisco Discovery Protocol (CDP) if available. If an Access Point that is web managed is identified, the security configuration of the Access Point is audited via HTML parsing. -Windows tools useful when associated with Wi-Fi tools: MacIdChanger MacIdChanger allows you to easily and temporarily change the MAC Address of your windows network adapter without much fuss. This is generally used to conceal the unique mac id that is on every network adapter. This software only operates on Windows XP/2003. Technetium MAC Address Changer Free, and very verbose and functional tool to change your network adapters MAC Address. The tool works regardless of which network adapter or driver is installed in your system. Supported platforms are Windows NT, Windows 2000, Windows XP and Windows Vista. -Wi-Fi Implementation Cost: Citywide blanket coverage of wireless Internet access sounds great, but companies aren't going to go around setting up Wi-Fi base stations out of sheer kindness. Who's going to pay for Wi-Fi? It depends how it will be used. There are two ways Wi-Fi can be implemented -- as a zone for wireless connections that single users go to when they want to connect to the Internet on a laptop (the non-line-of-sight "super Wi-Fi" implementation), or as a line-of- 28 CE51100-1 - Fundamentals of Computer Networks 2010
  29. 29. 29 CE51100-1 - Fundamentals of Computer Networks 2010 sight hub used to connect hundreds of customers to a steady, always-on, high-speed wireless Internet connection. Under the "super Wi-Fi" plan, cities might pay to have WiMAX base stations set up in key areas for business and commerce and then allow people to use them for free. They already do this with Wi-Fi, but instead of putting in a bunch of Wi-Fi hot spots that cover a few hundred square yards, a city could pay for one WiMAX base station and cover an entire financial district. This could provide a strong draw when city leaders try to attract businesses to their area. Some companies might set up WiMAX transmitters and then make people pay for access. Again, this is similar to strategies used for WiFi, but a much wider area would be covered. Instead of hopping from one hot spot to another, WiMAX-enabled users could have Internet access anywhere within 30 miles of the WiMAX base station. These companies might offer unlimited access for a monthly fee or a "pay as you go" plan that charges on a per-minute or per-hour basis. The high-speed wireless hub plan has the potential to be far more revolutionary. If you have high-speed Internet access now, it probably works something like this: The cable (or phone) company has a line that runs into your home. That line goes to a cable modem, and another line runs from the modem to your computer. If you have a home network, first it goes to a router and then on to the other computers on the network. You pay the cable company a monthly fee, which reflects in part the expense of running cable lines to every single home in the neighborhood. 29 CE51100-1 - Fundamentals of Computer Networks 2010
  30. 30. 30 CE51100-1 - Fundamentals of Computer Networks 2010 The other good thing for people wanting to set up a Wi-Fi network is that the prices of Wi-Fi access points and radios are falling sharply. The cost of a Wi-Fi radio chip which was around 50 rm in 2002 will drop to under 7 rm in 2006.Similarly the cost of Wi-Fi. Access points which were around 3200 rm in 2002 are under 320 rm now and are expected to fall further. Also the Wi-fi card that was around 2200 rm in 2000 is almost under 160 rm now and is approaching to be provided as a standard feature in most of the new PC's being manufactured today. Because of these low price to set up a Wi-Fi network and without any licence fees to be paid millions of wi-Fi networks have been set up as they also provide better speeds as compared to the traditional broadband and cellular networks. The default installed cost per unit for a single access point is 3200 rm. The overall cost estimate (default, suggested values) for a wireless network with 13 access points is 251,520 rm, providing support for 250 employees. This cost includes 32,000 rm for the design (site survey), 800 rm for each of the 13 Ethernet drops, and 800 rm for each of the 13 power supplies (including Power-over-Ethernet). -Special considerations of Wi-Fi implementation:-Safety: Wireless networks use radio waves to transmit information between wired router stations and the wireless adapter cards in laptop computers. The radio waves emitted by Wi-Fi networks are typically at frequencies of 2.4 Gigahertz (GHz) or 5.8 GHz - well within that portion of the electromagnetic spectrum defined to be radiofrequency radiation. This radiation is much lower in energy than ionizing radiation (e.g. the type of radiation emitted by x-ray machines), and the biological effects associated with exposure are much different. The long-recognized and well understood adverse biological effect resulting from exposure to high levels of RF exposure is tissue and cell heating. More recently concerns have been raised about whether there may be effects, including carcinogenicity, at RF levels below those levels that produce detectably harmful heating. Many studies have 30 CE51100-1 - Fundamentals of Computer Networks 2010
  31. 31. 31 CE51100-1 - Fundamentals of Computer Networks 2010 been conducted to determine whether there is a causal relationship between low-level radiofrequency exposure and harmful effects such as cancer and adverse pregnancy outcomes. -security: Nowadays Wi-Fi is becoming more and more popular used by the people in varied places, home, office, malls, new buildings, and even in parks. So as we need to create a Wi-Fi network we have to ensure that our security point isn’t accessible to anyone can get our network easily or hack through the network because it can be dangerous on our precious files and information that we keep it in our personal computers. Almost all routers and access points have an administrator password that's needed to log into the device and modify any configuration settings. Most devices use a weak default password like "password" or the manufacturer's name, and some don't have a default password at all. As soon as you set up a new WLAN router or access point, your first step should be to change the default password to something else. You may not use this password very often, so be sure to write it down in a safe place so you can refer to it if needed. Without it, the only way to access the router or access point may be to reset it to factory default settings which will wipe away any configuration changes you've made. Reduce your WLAN transmitter power: You won't find this feature on all wireless routers and access points, but some allow you lower the power of your WLAN transmitter and thus reduce the range of the signal. Although it's usually impossible to fine-tune a signal so precisely that it won't leak outside your home or business, with some trial-and-error you can often limit how far outside your premises the signal reaches, minimizing the opportunity for outsiders to access your WLAN. -Rules and Regulation: 31 CE51100-1 - Fundamentals of Computer Networks 2010
  32. 32. 32 CE51100-1 - Fundamentals of Computer Networks 2010 The Ministry of Communications, Department of Telecommunications (DoT) Malaysia has introduced significant new compliance requirements for all ISPs providing Wi-Fi services. The regulation goes beyond just public hotspots to include residential and business Wi-Fi applications, extending requirements of centralized management, authentication and provisioning by the ISP even for all customers who may have installed Wi-Fi access points within their premises. SP must ensure that all Wi-Fi access points be encrypted & secured. The list of locations includes: • • • • Public hotspots including airports, transportation hubs, schools Hotels, restaurants, guest houses, malls & similar locations Business and offices who use leased lines and install their own Wi-Fi Access Points (APs) also need to be secured Residential & Retail customers who install Wi-Fi Access Points also need to be secured or risk suspension of their Internet access • Service providers must offer central authentication and tracking system to secure all Wi-Fi end points ensuring each subscriber’s access sessions are authorized and tracked. o Records of subscriber records need to be kept for minimum 1 year. o Records must also include user metrics for full audit trace • Identity verification of each subscriber is mandatory and must be accomplished in the following ways: o Photo identity based verification using well established address proof documents such as PAN, Passport, Driver License; o Personal Identification needs to be copied and retained for 1 year; o SMS based authentication of each session/subscriber thereby establishing a direct co-relation between a pre-verified mobile phone and a subscriber. Avoiding Internet DoT License Suspension requires ISPs to: • • • Ensure only secure and authorized subscribers are allowed network access at all wireless end points; Accurately ascertain network access and retain records of subscriber activity including IP address & location where / when an authorized user accessed a specified Internet resource; ISPs must, upon lawful request, enable interception and tracking capabilities for agencies to track unlawful activity. -Advantages and Disadvantages of Wi-Fi Technology:- 32 CE51100-1 - Fundamentals of Computer Networks 2010
  33. 33. 33 CE51100-1 - Fundamentals of Computer Networks 2010 -Advantages / strengths for implementing Wi-Fi technology: • • • • • • Wi-Fi uses unlicensed radio spectrum and does not require regulatory approval for individual deplorers. It allows local area networks (LANs) to be setup with cabling. The can reduce associated costs of network connection and expansions. Places where cables cannot be run, such as outdoor areas and historical buildings can use wireless LANs. Wi-Fi products are extensively available in the market. There are different brands of access points and user's network interfaces are able to inter-operate at a very basic service level. Prices are considerably lower as competition amongst vendors' increases. Wi-Fi networks can support roaming. This allows mobile users with laptop computer to be able to move from one access point to another. Numerous access points and network interfaces support various degrees of encryption to protect traffic from interception. -Disadvantages / strengths for implementing Wi-Fi technology: Due the fact that Wi-Fi is still relatively new, there are considerably more disadvantages to users. Let's have a look at them: • • • • • 33 The use of Wi-Fi band that is 2.4 GHz does not require a license in most countries provided that is stays below limit of 100mW and one accepts interference from other sources; including interference which causes the users devices to no longer function. The spectrum assignments and operational limitations are not consistent worldwide. Power consumption is fairly high compared to some other standards, making the battery life and heat a concern to some users. Wi-Fi uses the unlicensed 2.4GHz spectrum, which often crowded with other devices such as Bluetooth, microwave ovens, cordless phones, or video sender devices, and among many others. This may cause degradation in performance. Wi-Fi networks have limited range. A typical Wi-Fi home router might have a range of 45m (150ft) indoors and 90m (300ft) outdoors. Ranges may also vary as CE51100-1 - Fundamentals of Computer Networks 2010
  34. 34. 34 CE51100-1 - Fundamentals of Computer Networks • • • • • 34 2010 Wi-Fi is no exception to the physics of radio wave propagation with frequency band. The most common wireless encryption standard, wired equivalent privacy or WEP has been shown to be breakable even when it has been correctly configured. Access points could be used to steal personal and confidential information transmitted from Wi-Fi consumers. Intervention of a closed or encrypted access point with other open access points on the same or a nearby channel can prevent access to the open access points by others in the area. It poses a high problem in high-density areas such as large apartment blocks where many residents are operating Wi-Fi access points. Inter-operability issues between brands or deviations can cause limited connection or lower output speeds. Free access points can be used by the malicious to anonymous to initiate an attack that would be extremely difficult to track beyond the owner of the access point. CE51100-1 - Fundamentals of Computer Networks 2010
  35. 35. 35 CE51100-1 - Fundamentals of Computer Networks 35 CE51100-1 - Fundamentals of Computer Networks 2010 2010