PRACTICAL - 1 AIM: - Familiarization with Computer Hardware CD ROM A CD-ROM drive uses an optically read plastic coated disk. The information is recorded on the surface of the disk in small holes aligned along a spiral from the center to edge. The drive directs a laser beam along the spiral to read the disk. When the laser hits the hole the laser is reflected in  the one way, when it hits the smooth surface it is reflected in another way. This makes it easy to code bits and therefore information. The rest is easy, mere mechanics. Short form is Compact Disk Read Only Memory. CD ROM drives are CD players inside of the computer that can range of speed from 1x and beyond and has the capability of playing audio CDs and also computer data CDs. Internal picture of a CD_ROM is shown below.CD-ROM, in computer science, acronym for compact disc read-only memory, a rigid plastic disk that stores a large amount of data through the use of laser optics technology. Because they store data optically, CD-ROMs have a much higher memory capacity than computer disks that store data magnetically. However, CD- ROM drives, the devices used to access information on CD-ROMs, can only read information from the disc, and not write to it. CD-ROMs and Audio CDs are almost exactly alike in structure and data format. The difference between the two lies in the device used to read the data—either a CD-ROM player or a compact disc (CD) player. CD-ROM players are used almost exclusively as computer components or peripherals. They may be either internal (indicating they fit into a computer‘s housing) or external (indicating they have their own housing and are connected to the computer via an external port). Both types of players spin the discs to access data as they read the data with a laser device. CD- ROM players only spin the disc to access a sector of data and copy it into main memory for use by the computer, while audio CDs spin throughout the time that the audio recording is read out, directly feeding the signal to an audio amplifier. The most important distinguishing feature among CD-ROM players is their speed, which indicates how fast they can read data from the disc. A single-speed CD-ROM player reads 150,000 bytes of data per second. Double-speed (2X), triple-speed (3X), quadruple-speed (4X), six-time speed (6X), and eight-times speed (8x) CD-ROM players are also widely available. Other important characteristics of CD-ROM players are seeking time and data transfer rate. The seek time (also called the access time) measures how long it takes for the laser to access a particular segment of data. A typical CD-ROM takes about a third of a second to access data, as compared to a typical hard drive, which takes about 10 milliseconds (thousandths of a second) to access data. The data transfer rate measures how quickly data is transferred from the disk media to the computer‘s main memory.  CD-ROM COMPACT DISK Storing Data on Compact Discs Data stored on a compact disc (CD) and on two variations of the CD, the compact disc- recordable (CD-R) and the compact disc-rewriteable (CD-RW), is read by bouncing a low-  powered laser off the disc and analyzing the reflection. The three formats differ, however, in the method employed to record data. On a CD, data is stored as a pattern of unreflective pits pressed into a layer of highly reflective aluminum (Al) at a factory. On a CD-R, a higher-powered laser burns areas of a transparent dye that lies over a reflective layer, turning specks of dye opaque and creating virtual pits that prevent the lower-powered read laser from being reflected. Once burned the dye cannot be made transparent again. A CD-RW has a layer of metal phase-change film that can switch between a highly reflective phase and a no reflective phase. When a higher-powered laser melts specks of the metal film, the specks cool quickly and become non-reflective, similar to the pits on a CD. However, the metal film can be made reflective again (erased) by heating it with a medium-powered laser that allows the film to cool slowly. Two layers of dielectric film sandwich the metal film and help The underside of the plastic CD-ROM disk is coated with a very thin layer of aluminum that reflects light. Data is written to the CD-ROM by burning microscopic pits into the reflective surface of the disk with a powerful laser. The data is in digital form, with pits representing a value of 1 and flat spots, called land, representing a value of 0. Once data is written to a CD- ROM, it cannot be erased or changed, and this is the reason it is termed read-only memory. Data is read from a CD-ROM with a low power laser contained in the drive that bounces light— usually infrared—off of the reflective surface of the disk and back to a photo detector. The pits in the reflective layer of the disk scatter light, while the land portions of the disk reflect the laser light efficiently to the photo detector. The photo detector then converts these light and dark spots to electrical impulses corresponding to 1s and 0s. Electronics and software interpret this data and accurately access the information contained on the CD-ROM. CD-ROMs can store large amounts of data and so are popular for storing databases and multimedia material. The most common format of CD-ROM holds approximately 630 megabytes (see Byte). By comparison, a regular floppy disk holds approximately 1.44 megabytes. The computer industry also manufactures blank, recordable compact discs, called CD-Rs (compact disc-recordable), that users can record data onto for one-time, permanent storage using  CD-R drives. Compact disc-rewriteable (CD-RWs) are similar to CD-Rs, but can be erased and rewritten multiple times. Another technology that allows the user to write to a compact disc is the magneto-optical (MO) disk, which combines magnetic and optical data storage. Users can record, erase, and save data to these disks any number of times using special MO drives. A CD is encoded with tiny pits that are arranged to represent the binary code of the recorded material. A laser beam is used to read the binary code off of the reflective surface of the disc. The light beam is either reflected back from the flat surface or dispersed when the beam strikes a pit. A sensor records whether the light is reflected or dispersed, and based on these changing values, the CD player reconstructs the original binary code of the recorded sound. The digital audio format of a CD allows for more than one hour of stereo music. The diameter of a disc is 12.07 cm (4.75 in). The data are recorded from the inside of the disc outwardly in a continuous spiral of tracks. CDs can also be used for digital storage of photographs, film and video footage, software, or any combination of these. Videodiscs, which are larger than CDs and hold much more information, are used for storage of film. Many feature-length movies are available in this format. Videodiscs are 30.48 cm (12.00 in) in diameter and can be recorded on both sides. Digital Video Discs (DVDs) are replacing videodiscs as a format for viewing movies and are also popular as a format for large multimedia programs for computers. DVDs are the same size as CDs but are more densely recorded, so more information can be fitted on a disc. A blank MD is recordable. It uses what is called magneto-optical technology to record and play music. Instead of pits and smooth surfaces, a blank MD uses tiny magnetic particles embedded within the shiny surface of the MD to store the digital code. To record digital data on an MD, a laser heats very small spots on the surface of the MD for a fraction of a second. An electromagnetic recording head applies a magnetic charge, aligning the particles in either a north or south direction, corresponding to the 0s and 1s of the digital data. On playback, a laser beam set at a lower temperature is aimed at the MD. The shiny surface of the MD reflects the laser light into a sensor. The differently aligned magnetic particles reflect the laser light in different  ways, and the sensor converts the changes into a digital code. A computer uses the digital code to reconstruct the sound that was originally recorded HARD DISK The inside of a computer hard disk drive consists of four main components. The round disk platter is usuall y made of aluminum, glass, o r ceramic and is coated with a magnetic media that contains all the data stored on the hard drive. The yellow arm like device that extends over the disk platter is known as the head arm and is the device that reads the information off of the disk platter. The head arm is attached to the head actuator, which controls the head arm. Not shown is the chassis which encases and holds all the hard disk drive components. Memory stored on external magnetic media includes magnetic tape, a hard disk, and a floppy disk. Magnetic tape is a form of external computer memory used  primaril y for backup storage. Like the surface on a magnetic disk, the surface of tape is coated with a material that can be magnetized. As the tape passes over an electromagnet, individual bits are magneticall y encoded. Computer systems using magnetic tape storage devices employ machinery similar to that used with analog tape: open -reel tapes, cassette tapes, and helical -scan tapes (similar to video tape). Another form of magnetic memory uses a spinning disk coated with magnetic material. As the disk spins, a sensitive electromagnetic sensor, called a read - write head, scans across the surface of the disk, reading and writing magnetic spots in concentric circles called tracks. Magnetic disks a re classified as either hard or floppy, depending on the flexibilit y of the material from which they are made. A floppy disk is made of flexible plastic with small pieces of a magnetic material imbedded in its surface. The read-write head touches the surfa ce of the disk as it scans the floppy. A hard disk is made of a rigid metal, with the read -write head flying just above its surface on a cushion of air to prevent wear. Disk Drive, in computer science, a device that reads or writes data, or both, on a disk medium. The disk medium may be either magnetic, as with floppy disks or hard disks; optical, as with CD -ROM (compact disc -read onl y memory) disks; or a combination of the two, as with magneto -optical disks. Nearl y all computers come equipped with drives f or these t ypes of disks, and the drives are usuall y inside the computer, but may also be connected as external, or peripheral, devices.  The main components of a disk drive are the motor, which rotates the disk; the read-write mechanism; and the logic board , which receives commands from the operating system to place or retrieve information on the disk. To read or write information to a disk, drives use various methods. Floppy and hard drives use a small magnetic head to magnetize portions of the disk surface , CD-ROM and WORM (Write-Once-Read-Many) drives use lasers to read information, and magneto-optical drives use a combination of magnetic and optical techniques to store and retrieve information. Floppy and hard disk drives store information on magnetic di sks. The disk itself is a thin, flexible piece of plastic with tiny magnetic particles imbedded in its surface. To write data to the disk, the read -write head creates a small magnetic field that aligns the magnetic poles of the particles on the surface of the disk directl y beneath the head. Particles aligned in one direction represent a 0 while particles aligned in the opposite direction represent a 1. To read data from a disk, the drive head scans the surface of the disk. The magnetic fields of the particles in the disk induce an alternating electric current in the read -write head, which is then translated into the series of 1s and 0s that the computer understands. THE PLATTERS The platters are actual disks inside the drive that store the magnetized data. Traditionall y platters are made up of alight aluminum alloy and coated with magneticall y material such as a ferrite compound that is applied in liquid form and spun evenl y across the platter or thin metal film plating that is applied to the platter through electroplating, the same way chrome is produced. Most drives have at least 2 platters and the larger the storage capacit y of the drive, the more platters there are.  THE SPINDLE MOTOR The platters in a drive are separated by disk spacers and are clamped to a rotating spindle that turns all the platters in unison. The spindle motor is build right into the spindle or mounted directly below it and spins the platters at a constant set range ranging from 3600 to 7200 RPM. The motor is attached to the feedback loop to ensure that it spins at precisel y the speed it is supposed to. THE READ/WRITE HEADS The read/write heads read and write data to the platters. There is t ypicall y one head per platter side, and each head is attached to a single actuator shaft so that all the head move in unison. When one head is over a track, all the other heads are at same location over their respective surfaces. Typically, onl y one of the heads is active at a time, i.e., reading or writing data. When not in use, the heads rest o n the stationary platters, but when in motion the spinning of the platters create air pressure that lifts the heads off the platters. The space between the platter and the head is so minute that even one dust particle or a fingerprint could disable the spi n. This necessitates that the hard drive assembl y be done in clean room. When the platters cease spinning the heads come to rest, or park, at a predetermined position on the heads, called the landing zone. THE HEAD ACTUATOR All the heads are attached to a single head actuator arm that moves the heads around the platters. Older hard drives used a stepper motor actuator, which moved the heads based on a motor reacting to stepper pulses. Each pulse moved the actuator over the platters in predefined steps. St epper motor actuators are not used in modern drives because they are prone to alignment problems and are  highl y sensitive to heat. Modern hard drives use a voice coil actuator, which controls the movement of a coil toward or away from a permanent magnet ba sed on the amount of current flowing through it. This guidance system is called a servo. The platters, spindle, spindle motor, head actuator and the read/write heads are all contained in a chamber called the head dish assembl y (HDA). Outside of the HAD is the logic board that controls the movements of data into and out of the drive. FLOPPY DISK Floppy Disk, in computer science, a round, flat piece of Mylar coated with ferric oxide, rust like substance containing tiny particles capable of holding a magnetic field, and encased in a protective plastic cover, the disk jacket. Data is stored on a floppy disk by the disk drive's read/write head, which alters the magnetic orientation of the particles. Orientation in one direction represents binary 1; orientation in the other, binary 0. Typicall y, a floppy disk is 5.25 inches in diameter, with a large hole in the center that fits around the spindle in the disk drive. Depending on its capacit y, such a disk can hold from a few hundred thousand to over one million bytes of data. A 3.5 -inch disk encased in rigid plastic is usually called a microfloppy disk but can also be called a floppy disk MOTHERBOARD  Motherboard, in computer science, the main circuit board in a computer. The most important computer chips and other electronic components that give function to a computer are located on the motherboard. The motherboard is a printed circuit board that connects the various elements on it through the use of traces, or electrical pathways. The motherboard contains the connectors for attaching additional boards. The motherboard contains the CPU, BIOS, memory mass storage interfaces, serial and parallel ports, expansion slots and all the controllers required to control standard peripheral devices, such as display screen, keyboard, mouse and disk drive. Collectivel y all these chips that reside on the motherboard are known as motherboard chipset. The motherboard is a central element of the personal computer, the main circuit board to which one connects memory, peripheral s and other devices, which extend the capabilities of the computer. The motherboard is indispensable to the computer and provides the main computing capabilit y. Personal computers normall y have one central processing unit (CPU), or microprocessor, which is located with other chips on the motherboard. The manufacturer and model of the CPU chip carried by the motherboard is a key  criterion for designating the speed and other capabilities of the computer. The CPU in many personal computers is not permanentl y a ttached to the motherboard, but is instead plugged into a socket so that it may be removed and upgraded. Motherboards also contain important computing components, such as the basic input/output system (BIOS), which contains the basic set of instructions required to control the computer when it is first turned on; different t ypes of memory chips such as random access memory (RAM) and cache memory; mouse, keyboard, and monitor control circuitry; and logic chips that control various parts of the computer‘s fun ction. Having as many of the key components of the computer as possible on the motherboard improves the speed and operation of the computer. Users may expand their computer‘s capabilit y by inserting an expansion board into special expansion slots on the mo therboard. Expansion slots are standard with nearl y all personal computers and offer faster speed, better graphics capabilities, communication capabilit y with other computers, and audio and video capabilities. Expansion slots come in either half or full size, and can transfer 8 or 16 bits (the smallest units of information that a computer can process) at a time, respectivel y. The pathways that carry data on the motherboard are called buses. The amount of data that can be transmitted at one time between a device, such as a printer or monitor, and the CPU affects the speed at which programs run. For this reason, buses are designed to carry as much data as possible. To work properl y, expansion boards must conform to bus standards such as integrated drive  electronics (IDE), Extended Industry Standard Architecture (EISA), or small computer system interface (SCS I). MOUSE A mouse is a pointing device that helps a user navigates through a graphical computer interface. Connected to the computer by a c able, it is generall y mapped so that an on -screen cursor may be controlled by moving the mouse across a flat surface. Two common types of mouse, the Microsoft mouse (bottom) and the Apple ADB (Apple Desktop Bus) mouse ( top) are shown here. Mouse (computer), a common pointing device, popularized by its inclusion as standard equipment with the Apple Macintosh. With the rise in popularit y of graphical user interfaces (Graphical User Interface) in MS -DOS; UNIX, and OS/2, use of mice is growing throughout the personal computer and workstation worlds. The basic features of a mouse are a casing with a flat bottom, designed to be gripped by one hand; one or more buttons on the top; a multidirectional detection device (usuall y a ball) on the bottom; and a cable con necting the mouse to the computer. See the illustration. By moving the mouse on a surface (such as a desk), the user t ypicall y controls an on -screen cursor. A mouse is a relative pointing device because there are no defined limits to the mouse's movement and because its placement on a surface does not map directl y to a  specific screen location. To select items or choose commands on the screen, the user presses one of the mouse's buttons, producing a ―mouse click. Bus Mouse, in computer science, a mouse that attaches to the computer's bus through a special card or port rather than through a serial port. Mechanical Mouse, in computer science, a t ype of mouse in which the motion of a ball on the bottom of the mouse is translated into directional signals. As the user moves the mouse, the ball t ypicall y spins a pair of wheels inside the mouse. These conductive wheels might, in turn, rotate additional wheels via axles or gears. At least one pair of wheels has conductive markings on their surface. Because the markings permit an electric current to flow, a set of conductive brushes that ride on the surface of the conductive wheels can detect the conductive markings. The electronics in the mouse translate these electrical -movement signals into mouse - movement informatio n that can be used by the computer. OPTICAL MOUSE Optical Mouse, in computer science, a type of mouse that uses a pair of light - emitting diodes (LEDs) and a special reflective grid pad to detect motion. The two lights are of different colors, and the sp ecial mouse pad has a grid of lines in the same colors, one color for vertical lines and another for horizontal lines. Light detectors paired with the LEDs sense when a colored light passes over a line of the same color, indicating the direction of the m ovement. See also Mechanical Mouse; Optomechanical Mouse; Pointing Device. OPTOMECHANICAL MOUSE As a mouse is moved, a ball in the mouse‘s interior is rolled. This motion turns two axles, corresponding to the two dimensions of movement. Each axle spins a slotted wheel. On one side of each wheel, a light -emitting diode (LED) sends a  path of light through the slots to a receiving phototransistor on the other side. The pattern of light to dark is then translated to an electrical signal, which reports the mou se‘s position and speed and is reflected in the movement of the cursor on the computer‘s screen. Optomechanical Mouse, in computer science, a t ype of mouse in which motion is translated into directional signals through a combination of optical and mechanical means. The optical portion includes pairs of light -emitting diodes (LEDs) and matching sensors; the mechanical portion consists of rotating wheels with cutout slits. When the mouse is moved, the wheels turn and the light from the LEDs either passes through the slits and strikes a light sensor or is blocked by the solid portions of the wheels. These chan ges in light contact are detected by the pairs of sensors and interpreted as indications of movement. Because the sensors are slightl y out of phase with one another, the direction of  movement is determined by which sensor is the first to regain light conta ct. Because it uses optical equipment instead of mechanical parts, an optomechanical mouse eliminates the need for many of the wear -related repairs and maintenance necessary with purel y mechanical mice, but it does not require the special operating surface s associated with optic mice. Serial Mouse, in computer science, a mouse that attaches to the computer through a standard serial port of the type that can also be used for other purposes, such as attaching a modem. If a serial port is unavailable or anoth er serial port cannot be added to the system, however, a bus mouse, which uses its own computer card, might be used instead. TRACKBALL A trackball is basicall y an inverted mouse; the user rotates the ball itself while clicking nearby buttons. Trackball users argue the device is more efficient because it is stationary and saves arm movement; however, many mouse users are uncomfortable with the different style of input. Trackball, in computer science, a popular pointing device that can be roughl y described as a mouse on its back. A trackball consists of a ball resting on two rollers at right angles to each other, which translate the ball's motion into vertical and horizontal movement on the screen. A trackball also t ypicall y has one or more buttons to initiate other actions. The onl y functional difference between a mechanical  mouse and a trackball is in how the ba ll is moved: With a mouse, the ball is rolled by moving the entire unit over a desktop or other surface; with a trackball, the housing is stationary, and the ball is rolled with the hand. A trackball is useful for fine work because the user can exert finge rtip control; a mouse is better for bold moves, such as those used in navigating within a graphical user interface. Another major advantage of a trackball is that i t takes little desktop surface.  PRACTICAL – 2 AIM :- Introduction with network computing A computer network is an interconnection of a group of computers. Networks may be classified by what is called the network layer at which they operate according to basic reference models considered as standards in the industry such as the four-layer Internet Protocol Suite model. While the seven-layer Open Systems Interconnection (OSI) reference model is better known in academia, the majority of networks use the Internet Protocol Suite (IP) as their network model. By scale Computer networks may be classified according to the scale: Personal area network (PAN), Local Area Network (LAN), Campus Area Network (CAN), Metropolitan area network (MAN), or Wide area network (WAN). As Ethernet increasingly is the standard interface to networks, these distinctions are more important to the network administrator than the end user. Network administrators may have to tune the network, based on delay that derives from distance, to achieve the desired Quality of Service (QoS). The primary difference in the networks is the size. Controller Area Networks are a special niche, as in control of a vehicle's engine, a boat's electronics, or a set of factory robots. By connection method Computer networks may be classified according to the hardware technology that is used to connect the individual devices in the network such as Optical fiber, Ethernet, Wireless LAN, HomePNA, or Power line communication. Ethernets use physical wiring to connect devices. Often, they employ the use of hubs, switches, bridges, and routers. Wireless LAN technology is built to connect devices without wiring. These devices use a radio frequency to connect.  By functional relationship (Network Architectures) Computer networks may be classified according to the functional relationships which exist between the elements of the network, for example Active Networking, Client-server and Peer-to- peer (workgroup) architectures. By network topology Computer networks may be classified according to the network topology upon which the network is based, such as Bus network, Star network, Ring network, Mesh network, Star-bus network, Tree or Hierarchical topology network, etc. Network Topology signifies the way in which intelligent devices in the network see their logical relations to one another. The use of the term "logical" here is significant. That is, network topology is independent of the "physical" layout of the network. Even if networked computers are physically placed in a linear arrangement, if they are connected via a hub, the network has a Star topology, rather than a Bus Topology. In this regard the visual and operational characteristics of a network are distinct; the logical network topology is not necessarily the same as the physical layout. By protocol Computer networks may be classified according to the communications protocol that is being used on the network. See the articles on List of network protocol stacks and List of network protocols for more information. For a development of the foundations of protocol design see Srikant 2004  and Meyn 2007  Types of networks: Below is a list of the most common types of computer networks in order of scale. Personal Area Network (PAN) A personal area network (PAN) is a computer network used for communication among computer devices close to one person. Some examples of devices that may be used in a PAN are printers, fax machines, telephones, PDAs or scanners. The reach of a PAN is typically within about 20-30  feet (approximately 4-6 Meters). PANs can be used for communication among the individual devices (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink). Personal area networks may be wired with computer buses such as USB and FireWire. A wireless personal area network (WPAN) can also be made possible with network technologies such as IrDA and Bluetooth. Local Area Network (LAN) A network covering a small geographic area, like a home, office, or building. Current LANs are most likely to be based on Ethernet technology. For example, a library will have a wired or wireless LAN for users to interconnect local devices (e.g., printers and servers) connect to the internet. All of the PCs in the library are connected by category 5 (Cat5) cable, running the IEEE 802.3 protocol through a system of interconnection devices and eventually connect to the internet. The cables to the servers are on Cat 5e enhanced cable, which will support IEEE 802.3 at 1 Gbps. The staff computers (bright green) can get to the color printer, checkout records, and the academic network and the Internet. All user computers can get to the Internet and the card catalog. Each workgroup can get to its local printer. Note that the printers are not accessible from outside their workgroup. Typical library network, in a branching tree topology and controlled access to resources All interconnect devices must understand the network layer (layer 3), because they are handling multiple subnets (the different colors). Those inside the library, which have only 10/100 Mbps Ethernet connections to the user device and a Gigabit Ethernet connection to the central router, could be called "layer 3 switches" because they only have Ethernet interfaces and must understand IP. It would be more correct to call them access routers, where the router at the top is a distribution router that connects to the Internet and academic networks' customer access routers. Depending on the circumstance, the computers in the network might be connected using cables and hubs. Other networks might be connected strictly wirelessly. It depends on the number of  PCs that you are trying to connect, the physical layout of your workspace, and the various needs of network. Not shown in this diagram, for example, is a wireless workstation used when shelving books. The defining characteristics of LANs, in contrast to WANs (wide area networks), include their much higher data transfer rates, smaller geographic range, and lack of a need for leased telecommunication lines. Current Ethernet or other IEEE 802.3 LAN technologies operate at speeds up to 10 Gbit/s. This is the data transfer rate. IEEE has projects investigating the standardization of 100 Gbit/s, and possibly 40 Gbit/s. Inverse multiplexing is commonly used to build a faster aggregate from slower physical streams, such as bringing 4 Gbit/s aggregate stream into a computer or network element with four 1 Gbit/s interfaces. Campus Area Network (CAN) A network that connects two or more LANs but that is limited to a specific and contiguous geographical area such as a college campus, industrial complex, or a military base. A CAN, may be considered a type of MAN (metropolitan area network), but is generally limited to an area that is smaller than a typical MAN. This term is most often used to discuss the implementation of networks for a contiguous area. For Ethernet based networks in the past, when layer 2 switching (i.e., bridging (networking) was cheaper than routing, campuses were good candidates for layer 2 networks, until they grew to very large size. Today, a campus may use a mixture of routing and bridging. The network elements used, called "campus switches", tend to be optimized to have many Ethernet-family (i.e., IEEE 802.3) interfaces rather than an arbitrary mixture of Ethernet and WAN interfaces. Metropolitan Area Network (MAN) A Metropolitan Area Network is a network that connects two or more Local Area Networks or Campus Area Networks together but does not extend beyond the boundaries of the immediate town, city, or metropolitan area. Multiple routers, switches & hubs are connected to create a MAN. Wide Area Network (WAN)  A WAN is a data communications network that covers a relatively broad geographic area (i.e. one city to another and one country to another country) and that often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer. Global Area Network (GAN) Global area networks (GAN) specifications are in development by several groups, and there is no common definition. In general, however, a GAN is a model for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is "handing off" the user communications from one local coverage area to the next. In IEEE Project 802, this involves a succession of terrestrial  Wireless local area networks (WLAN) . INMARSAT has defined a satellite-based Broadband Global Area Network (BGAN). IEEE mobility efforts focus on the data link layer and make assumptions about the media. Mobile IP is a network layer technique, developed by the IETF, which is independent of the media type and can run over different media while still keeping the connection. Internetwork Two or more networks or network segments connected using devices that operate at layer 3 (the 'network' layer) of the OSI Basic Reference Model, such as a router. Any interconnection among or between public, private, commercial, industrial, or governmental networks may also be defined as an internetwork. In modern practice, the interconnected networks use the Internet Protocol. There are at least three variants of internetwork, depending on who administers and who participates in them: Intranet Extranet "The" Internet  Intranets and extranets may or may not have connections to the Internet. If connected to the Internet, the intranet or extranet is normally protected from being accessed from the Internet without proper authorization. The Internet itself is not considered to be a part of the intranet or extranet, although the Internet may serve as a portal for access to portions of an extranet. Intranet An intranet is a set of interconnected networks, using the Internet Protocol and uses IP-based tools such as web browsers, that is under the control of a single administrative entity. That administrative entity closes the intranet to the rest of the world, and allows only specific users. Most commonly, an intranet is the internal network of a company or other enterprise. Extranet An extranet is a network or internetwork that is limited in scope to a single organization or entity but which also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities (e.g. a company's customers may be given access to some part of its intranet creating in this way an extranet, while at the same time the customers may not be considered 'trusted' from a security standpoint). Technically, an extranet may also be categorized as a CAN, MAN, WAN, or other type of network, although, by definition, an extranet cannot consist of a single LAN; it must have at least one connection with an external network. Internet A specific internetwork , consisting of a worldwide interconnection of governmental, academic, public, and private networks based upon the Advanced Research Projects Agency Network (ARPANET) developed by ARPA of the U.S. Department of Defense – also home to the World Wide Web (WWW) and referred to as the 'Internet' with a capital 'I' to distinguish it from other generic internetworks. Participants in the Internet, or their service providers, use IP Addresses obtained from address registries that control assignments. Service providers and large enterprises also exchange  information on the reachability of their address ranges through the BGP Border Gateway Protocol.  PRACTICAL – 3 AIM: - Introduction to client-server, peer to peer, direct cable connection networks. CLENT-SERVER Client-server is a computing architecture which separates a client from a server, and is almost always implemented over a computer network. Each client or server connected to a network can also be referred to as a node. The most basic type of client-server architecture employs only two types of nodes: clients and servers. This type of architecture is sometimes referred to as two-tier. It allows devices to share files and resources. Each instance of the client software can send data requests to one or more connected servers. In turn, the servers can accept these requests, process them, and return the requested information to the client. Although this concept can be applied for a variety of reasons to many different kinds of applications, the architecture remains fundamentally the same. The interaction between client and server is often described using sequence diagrams. Sequence diagrams are standardized in the Unified Modeling Language. Characteristics of a client Request sender is known as client Initiates requests Waits for and receives replies. Usually connects to a small number of servers at one time Typically interacts directly with end-users using a graphical user interface Characteristics of a server Receiver of request which is sent by client is known as server Passive (slave) Waits for requests from clients Upon receipt of requests, processes them and then serves replies  Usually accepts connections from a large number of clients Typically does not interact directly with end-users Multi-tiered architecture Some designs are more sophisticated and consist of three different kinds of nodes: clients, application servers which process data for the clients, and database servers which store data for the application servers. This configuration is called a three-tier architecture, and is the most commonly used type of client-server architecture. Designs that contain more than two tiers are referred to as multi-tiered or n-tiered. The advantages of n-tiered architectures is that they are far more scalable, since they balance and distribute the processing load among multiple, often redundant, specialized server nodes. This in turn improves overall system performance and reliability, since more of the processing load can be accommodated simultaneously. The disadvantages of n-tiered architectures include: 1. More load on the network itself, due to a greater amount of network traffic. 2. More difficult to program and test than in two-tier architectures because more devices have to communicate in order to complete a client's request. Advantages In most cases, a client-server architecture enables the roles and responsibilities of a computing system to be distributed among several independent computers that are known to each other only through a network. This creates an additional advantage to this architecture: greater ease of maintenance. For example, it is possible to replace, repair, upgrade, or even relocate a server while its clients remain both unaware and unaffected by that change. This independence from change is also referred to as encapsulation. All the data is stored on the servers, which generally have far greater security controls than most clients. Servers can better control access and resources, to guarantee that only those clients with the appropriate permissions may access and change data.  Since data storage is centralized, updates to those data are far easier to administer than would be possible under a P2P paradigm. Under a P2P architecture, data updates may need to be distributed and applied to each "peer" in the network, which is both time- consuming and error-prone, as there can be thousands or even millions of peers. Many mature client-server technologies are already available which were designed to ensure security, 'friendliness' of the user interface, and ease of use. It functions with multiple different clients of different capabilities. Disadvantages Traffic congestion on the network has been an issue since the inception of the client- server paradigm. As the number of simultaneous client requests to a given server increases, the server can become severely overloaded. Contrast that to a P2P network, where its bandwidth actually increases as more nodes are added, since the P2P network's overall bandwidth can be roughly computed as the sum of the bandwidths of every node in that network. The client-server paradigm lacks the robustness of a good P2P network. Under client- server, should a critical server fail, clients‘ requests cannot be fulfilled. In P2P networks, resources are usually distributed among many nodes. Even if one or more nodes depart and abandon a downloading file, for example, the remaining nodes should still have the data needed to complete the download. Examples Imagine you are visiting an e-commerce web site. In this case, your computer and web browser would be considered the client, while the computers, databases, and applications that make up the online store would be considered the server. When your web browser requests specific information from the online store, the server finds all of the data in the database needed to satisfy the browser's request, assembles that data into a web page, and transmits that page back to your web browser for you to view.  Specific types of clients include web browsers, email clients, and online chat clients. Specific types of servers include web servers, ftp servers, application servers, database servers, mail servers, file servers, print servers, and terminal servers. Most web services are also types of servers. PEER TO PEER A peer-to-peer (or "P2P", or, rarely, "PtP") computer network uses diverse connectivity between participants in a network and the cumulative bandwidth of network participants rather than conventional centralized resources where a relatively low number of servers provide the core value to a service or application. Peer-to-peer networks are typically used for connecting nodes via largely ad hoc connections. Such networks are useful for many purposes. Sharing content files (see file sharing) containing audio, video, data or anything in digital format is very common, and realtime data, such as telephony traffic, is also passed using P2P technology. A pure peer-to-peer network does not have the notion of clients or servers, but only equal peer nodes that simultaneously function as both "clients" and "servers" to the other nodes on the network. This model of network arrangement differs from the client-server model where communication is usually to and from a central server. A typical example for a non peer-to-peer file transfer is an FTP server where the client and server programs are quite distinct, and the clients initiate the download/uploads and the servers react to and satisfy these requests. The earliest peer-to-peer network in widespread use was the Usenet news server system, in which peers communicated with one another to propagate Usenet news articles over the entire Usenet network. Particularly in the earlier days of Usenet, UUCP was used to extend even beyond the Internet. However, the news server system also acted in a client-server form when individual users accessed a local news server to read and post articles. The same consideration applies to SMTP email in the sense that the core email relaying network of Mail transfer agents is a peer-to-peer network while the periphery of Mail user agents and their direct connections is client server. Some networks and channels such as Napster, OpenNAP and IRC server channels use a client- server structure for some tasks (e.g. searching) and a peer-to-peer structure for others. Networks  such as Gnutella or Freenet use a peer-to-peer structure for all purposes, and are sometimes referred to as true peer-to-peer networks, although Gnutella is greatly facilitated by directory servers that inform peers of the network addresses of other peers. Peer-to-peer architecture embodies one of the key technical concepts of the Internet, described in the first Internet Request for Comments, RFC 1, "Host Software" dated 7 April 1969. More recently, the concept has achieved recognition in the general public in the context of the absence of central indexing servers in architectures used for exchanging multimedia files. The concept of peer to peer is increasingly evolving to an expanded usage as the relational dynamic active in distributed networks, i.e. not just computer to computer, but human to human. Yochai Benkler has coined the term "commons-based peer production" to denote collaborative projects such as free software. Associated with peer production are the concept of peer governance (referring to the manner in which peer production projects are managed) and peer property (referring to the new type of licenses which recognize individual authorship but not exclusive property rights, such as the GNU General Public License and the Creative Commons licenses). Classifications of peer-to-peer networks Peer-to-peer networks can be classified by what they can be used for: file sharing telephony media streaming (radio, video) discussion forums Other classification of peer-to-peer networks is according to their degree of centralization. In 'pure' peer-to-peer networks: Peers act as equals, merging the roles of clients and server There is no central server managing the network There is no central router  Some examples of pure peer-to-peer application layer networks designed for file sharing are Gnutella and Freenet. There also exist countless hybrid peer-to-peer systems: Has a central server that keeps information on peers and responds to requests for that information. Peers are responsible for hosting available resources (as the central server does not have them), for letting the central server know what resources they want to share, and for making its shareable resources available to peers that request it. Route terminals are used addresses, which are referenced by a set of indices to obtain an absolute address. e.g. Centralized P2P network such as Napster Decentralized P2P network such as KaZaA Structured P2P network such as CAN Unstructured P2P network such as Gnutella Hybrid P2P network (Centralized and Decentralized) such as JXTA, GreenTea and Shwup Advantages of peer-to-peer networks An important goal in peer-to-peer networks is that all clients provide resources, including bandwidth, storage space, and computing power. Thus, as nodes arrive and demand on the system increases, the total capacity of the system also increases. This is not true of a client-server architecture with a fixed set of servers, in which adding more clients could mean slower data transfer for all users. The distributed nature of peer-to-peer networks also increases robustness in case of failures by replicating data over multiple peers, and -- in pure P2P systems -- by enabling peers to find the data without relying on a centralized index server. In the latter case, there is no single point of failure in the system.  When the term peer-to-peer was used to describe the Napster network, it implied that the peer protocol was important, but, in reality, the great achievement of Napster was the empowerment of the peers (i.e., the fringes of the network) in association with a central index, which made it fast and efficient to locate available content. The peer protocol was just a common way to achieve this. While the original Napster network was a P2P network, the newest version of Napster has no connection to P2P networking at all. The modern day version of Napster is a subscription based service which allows you to download music files legally. Unstructured and structured P2P networks The P2P overlay network consists of all the participating peers as network nodes. There are links between any two nodes that know each other: i.e. if a participating peer knows the location of another peer in the P2P network, then there is a directed edge from the former node to the latter in the overlay network. Based on how the nodes in the overlay network are linked to each other, we can classify the P2P networks as unstructured or structured. An unstructured P2P network is formed when the overlay links are established arbitrarily. Such networks can be easily constructed as a new peer that wants to join the network can copy existing links of another node and then form its own links over time. In an unstructured P2P network, if a peer wants to find a desired piece of data in the network, the query has to be flooded through the network to find as many peers as possible that share the data. The main disadvantage with such networks is that the queries may not always be resolved. Popular content is likely to be available at several peers and any peer searching for it is likely to find the same thing, but if a peer is looking for rare data shared by only a few other peers, then it is highly unlikely that search will be successful. Since there is no correlation between a peer and the content managed by it, there is no guarantee that flooding will find a peer that has the desired data. Flooding also causes a high amount of signalling traffic in the network and hence such networks typically have very poor search efficiency. Most of the popular P2P networks such as Gnutella and FastTrack are unstructured. Structured P2P network employ a globally consistent protocol to ensure that any node can efficiently route a search to some peer that has the desired file, even if the file is extremely rare. Such a guarantee necessitates a more structured pattern of overlay links. By far the most common type of structured P2P network is the distributed hash table (DHT), in which a variant of consistent hashing is used to assign ownership of each file to a particular peer, in a way analogous to a traditional hash table's assignment of each key to a particular array slot. Some well known DHTs are Chord, Pastry, Tapestry, CAN, and Tulip. Not a DHT-approach but a structured P2P network is HyperCuP. Comparison to Peer-to-Peer Architecture  Another type of network architecture is known as peer-to-peer, because each node or instance of the program can simultaneously act as both a client and a server, and because each has equivalent responsibilities and status. Peer-to-peer architectures are often abbreviated using the acronym P2P. Both client-server and P2P architectures are in wide usage today. Direct cable connection Direct Cable Connection (DCC), is a feature of Microsoft Windows that allows a computer to transfer and share files (or connected printers) with another computer, via a connection using either the serial port, parallel port or the infrared port of each computer. It is well-suited for computers that do not have an ethernet adapter installed, although DCC in Windows XP can be configured to use one (with a proper crossover cable if no network hub is used) if available. DCC with Serial Port If using the serial ports of the computer, a null modem cable (or a null modem adapter connected to a standard serial cable) must be used to connect each of the two computers to communicate properly. DCC with Parallel Port If the parallel ports are used, Windows supports standard or basic 4-bit cable (commonly known as LapLink cable), Enhanced Capabilities Port (ECP) cable, or Universal Cable Module (UCM) cable (which was known as DirectParallel cable by Parallel Technologies). DCC with IR Infrared communication ports, like the ones found on laptop computers (such as IrDA), can also be used. DCC with USB Connecting any two computers using USB requires a special proprietary bridge cable solution; the usual USB-to-USB cable does not work as USB does not support such type of  communication and attempting to do so may even damage the connecting computers as it can short the two computers' power supplies together, possibly destroying one or both machines or causing a fire hazard. Therefore, Direct Cable Connection over USB is not possible; a USB link cable must be used, as seen in the Microsoft knowledge base article 814982 shows. Windows Vista drops support for the Direct cable connection feature as ethernet, Wi-Fi and Bluetooth have become ubiquitous on current generation computers. To transfer files and settings, Windows Vista includes Windows Easy Transfer, which uses a proprietary USB-to- USB bridge cable made by Belkin.  PRACTICAL – 4 AIM: - Study of LAN components and it’s various topologies Basic LAN components There are essentially five basic components of a LAN Network Devices such as Workstations, Printers, File Servers which are normally accessed by all other computers Network Communication Devices i.e. devices such as hubs, routers, switches etc., used for network operations Network Interface Cards (NICs) for each network device required to access the network . Cable as a physical transmission medium. Network Operating System - software applications required to control the use of the network LAN standards.  All networks are made up of basic hardware building blocks to interconnect network nodes, such as Network Interface Cards (NICs), Bridges, Hubs, Switches, and Routers. In addition, some method of connecting these building blocks is required, usually in the form of galvanic cable (most commonly Category 5 cable). Less common are microwave links (as in IEEE 802.11) or optical cable ("optical fiber"). Network Interface Cards A network card, network adapter or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network. It provides physical access to a networking medium and often provides a low-level addressing system through the use of MAC addresses. It allows users to connect to each other either by using cables or wirelessly. Repeaters A repeater is an electronic device that receives a signal and retransmits it at a higher level or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances without degradation. Because repeaters work with the actual physical signal, and do not attempt to interpret the data being transmitted, they operate on the Physical layer, the first layer of the OSI model. Hubs A hub contains multiple ports. When a packet arrives at one port, it is copied to all the ports of the hub. When the packets are copied, the destination address in the frame does not change to a broadcast address. It does this in a rudimentary way, it simply copies the data to all of the Nodes connected to the hub.  Bridges A network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges do not promiscuously copy traffic to all ports, as hubs do. but learns which MAC addresses are reachable through specific ports. Once the bridge associates a port and an address,  it will send traffic for that address only to that port. Bridges do send broadcasts to all ports except the one on which the broadcast was received. Bridges learn the association of ports and addresses by examining the source address of frames that it sees on various ports. Once a frame arrives through a port, its source address is stored and the bridge assumes that MAC address is associated with that port. The first time that a previously unknown destination address is seen, the bridge will forward the frame to all ports other than the one on which the frame arrived. Bridges come in three basic types: 1. Local bridges: Directly connect local area networks (LANs) 2. Remote bridges: Can be used to create a wide area network (WAN) link between LANs. Remote bridges, where the connecting link is slower than the end networks, largely have been replaced by routers. 3. Wireless bridges: Can be used to join LANs or connect remote stations to LANs. Switches Switches are a marketing term that encompasses routers and bridges, as well as devices that may distribute traffic on load or by application content (e.g., a Web URL identifier). Switches may operate at one or more OSI layers, including physical, data link, network, or transport (i.e., end- to-end). A device that operates simultaneously at more than one of these layers is called a multilayer switch. Overemphasizing the ill-defined term "switch" often leads to confusion when first trying to understand networking. Many experienced network designers and operators recommend starting with the logic of devices dealing with only one protocol level, not all of which are covered by OSI. Multilayer device selection is an advanced topic that may lead to selecting particular implementations, but multilayer switching is simply not a real-world design concept. Routers Routers are the networking device that forward data packets along networks by using headers and forwarding tables to determine the best path to forward the packets. Routers work at the  network layer of the TCP/IP model or layer 3 of the OSI model. Routers also provide interconnectivity between like and unlike media (RFC 1812) This is accomplished by examining the Header of a data packet, and making a decision on the next hop to which it should be sent (RFC 1812) They use preconfigured static routes, status of their hardware interfaces, and routing protocols to select the best route between any two subnets. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP's network. Some DSL and cable modems, for home use, have been integrated with routers to allow multiple home computers to access the Internet. What is a Topology? The physical topology of a network refers to the configuration of cables, computers, and other peripherals. Physical topology should not be confused with logical topology which is the method used to pass information between workstations. Main Types of Physical Topologies Linear Bus A linear bus topology consists of a main run of cable with a terminator at each end (See fig. 1). All nodes (file server, workstations, and peripherals) are connected to the linear cable. Ethernet and LocalTalk networks use a linear bus topology. Fig. 1. Linear Bus topology Advantages of a Linear Bus Topology Easy to connect a computer or peripheral to a linear bus. Requires less cable length than a star topology.  Disadvantages of a Linear Bus Topology Entire network shuts down if there is a break in the main cable. Terminators are required at both ends of the backbone cable. Difficult to identify the problem if the entire network shuts down. Not meant to be used as a stand-alone solution in a large building. Star A star topology is designed with each node (file server, workstations, and peripherals) connected directly to a central network hub or concentrator .Data on a star network passes through the hub or concentrator before continuing to its destination. The hub or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow. This configuration is common with twisted pair cable; however, it can also be used with coaxial cable or fiber optic cable. Fig. 2. Star topology Advantages of a Star Topology Easy to install and wire. No disruptions to the network then connecting or removing devices. Easy to detect faults and to remove parts. Disadvantages of a Star Topology  Requires more cable length than a linear topology. If the hub or concentrator fails, nodes attached are disabled. More expensive than linear bus topologies because of the cost of the concentrators. The protocols used with star configurations are usually Ethernet or LocalTalk. Token Ring uses a similar topology, called the star-wired ring. Star-Wired Ring A star-wired ring topology may appear (externally) to be the same as a star topology. Internally, the MAU (multistation access unit) of a star-wired ring contains wiring that allows information to pass from one device to another in a circle or ring (See fig. 3). The Token Ring protocol uses a star-wired ring topology. Tree A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable (See fig. 4). Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs. Fig. 4. Tree topology Advantages of a Tree Topology  Point-to-point wiring for individual segments. Supported by several hardware and software venders. Disadvantages of a Tree Topology Overall length of each segment is limited by the type of cabling used. If the backbone line breaks, the entire segment goes down. More difficult to configure and wire than other topologies. 5-4-3 Rule A consideration in setting up a tree topology using Ethernet protocol is the 5-4-3 rule. One aspect of the Ethernet protocol requires that a signal sent out on the network cable reach every part of the network within a specified length of time. Each concentrator or repeater that a signal goes through adds a small amount of time. This leads to the rule that between any two nodes on the network there can only be a maximum of 5 segments, connected through 4 repeaters/concentrators. In addition, only 3 of the segments may be populated (trunk) segments if they are made of coaxial cable. A populated segment is one which has one or more nodes attached to it . In Figure 4, the 5-4-3 rule is adhered to. The furthest two nodes on the network have 4 segments and 3 repeaters/concentrators between them. Considerations When Choosing a Topology: Money. A linear bus network may be the least expensive way to install a network; you do not have to purchase concentrators. Length of cable needed. The linear bus network uses shorter lengths of cable. Future growth. With a star topology, expanding a network is easily done by adding another concentrator. Cable type. The most common cable in schools is unshielded twisted pair, which is most often used with star topologies.  Summary Chart: Physical Common Common Topology Cable Protocol Twisted Pair Ethernet Linear Bus Coaxial LocalTalk Fiber Twisted Pair Ethernet Star Fiber LocalTalk Star-Wired Twisted Pair Token Ring Ring Twisted Pair Tree Coaxial Ethernet Fiber  Practical – 5 Install and configure a network interface card in a workstation Safety Precautions: 1. To prevent static electricity from damaging vital components of your computer, remember to always attach an anti-static strip bracelet from your wrist to your computer case. 2. Computer cases were not meant to be opened by the everyday user and thus are not made with the safety of the user in mind. Be careful for sharp edges in the casing that can cut your fingers and/or hands. 3. Never remove a component or open a computer case while the power is on and the power cable attached. Always remove all connecting cables before opening your case. Opening the Case: 1. Shut off the system if it is on. 2. Remove all cables connecting to the computer. 3. Locate the screws holding the case cover in place on the frame. 4. Remove the screws attaching the cover to the frame. 5. Many new systems have tight cases and/or special cases. Removing the casing might require some prying. Use a flat-head screwdriver to push the case open against the front panel. Seek assistance if you cannot open the case alone. If the case seems really peculiar. Check your computer's user manual first to see if they instruct you on how to open your computer. Locating the Expansion Slots: 1. Place the open computer frame on its side with the motherboard facing up. This means you can see the motherboard from a bird's eye view. The motherboard is the biggest board you can see within the frame. It usually covers an entire side and has other smaller boards sticking up from it. 2. Looking at the motherboard, try to locate the expansion slots. Expansion slots are either long  black strips or short white strips that look like Lego blocks standing up. ISA slots are black. PCI slots are white. Open slots are those that do not have other boards inserted in them. Installing Your New Card: 1. Determine which interface (ISA or PCI) your card uses. ISA is long and the gold contacts are large. PCI is much shorter and smaller. 2. Next, check to see if the expansion slot opening next to the slot is covered. If it is, remove the cover by unscrewing it from the frame or popping it out. (IMPORTANT: Keep the screw and the slot cover.) If you have a new case that has slot covers built in you will have to remove them manually with a screwdriver. Please refer to your user manual for details. 3. When the slot cover has been removed, insert your card into the expansion slot on the motherboard. Press firmly so the entire part of the card that has the gold contacts goes completely into the expansion slot on the motherboard and will go no further. Do not use any tools to try to hammer the card in if it does not fit. 4. Make sure the side of the card resembling the expansion slot cover you just removed is covering most of the open slot. 5. Screw the card into place with the screw you removed from the expansion slot cover or a new screw. Replacing the Case: 1. After confirming the proper placement of the card, make sure you did not leave any tools or screws within the computer. Replace the case and screw it back in place. 2. Reconnect all the cables to their proper places. Booting Up: 1. Turn on the power. 2. Refer to your user's manual to install the proper drivers from the disk(s) that came with the card. 3. Refer to the section setting up and configuring your computer for ResNet for the settings you will need to access ResNet  Configuring your Network Interface Card: Network TCP/IP Configuration for Windows 95-98 Double click the My Computer icon on your desktop. Locate and double click on the Control Panel icon. Next double click the Network icon to open the Network Control Panel. Confirm Installation of your Ethernet Adapter Card: The Local Area Connection window will list the Network Adapters, Network Protocols, and Network Clients that you have installed on your system. The specific configuration will likely vary from the illustration below. If TCP/IP is already installed, it will appear in the list of installed protocols. Click once on the listed item Internet Protocol (TCP/IP) - this will select this item. Now click the Properties button. Verify both the Obtain an IP address automatically and the Obtain DNS server address automatically radio buttons are selected. Click on the Advanced button. In the Advanced TCP/IP Settings window, click on the DNS tab. Uncheck the box Register this connection's addresses in DNS toward the bottom of the screen. Click OK to close the Advanced TCP/IP Settings window. Click OK to close the Internet Protocol (TCP/IP) Properties window. Continue by clicking the OK button to close the Local Area Connection Properties window. Close the Network and Dial-up Connections window. Once you installed a new network card, windows will detect t he card, it will first display a message like:  ―PCI Ethernet card detected‖ and then it depends, whether your version of windows knows already the t ype of network card: Windows identified the network card and has a driver for i t in its own library: It will start installing immediatel y the driver and other network components Windows could not identify the network card and does not have a driver for it: You are prompted to provide the floppy disk/ CD provided by the manufacturer of the network card. Open the propert y option in ‗My computer‘. Select the tab ‖Hardware‖, then click in the section ―Device manager‖ on the button ―Device manager‖: look at  ―Network Adapters‖, click on the ―+‖ to display all installed adapters: now you are ready to continue to configure your network.  Practical – 6 AIM: - To Study different types of Cables used in networks What is Network Cabling? Cable is the medium through which information usually moves from one network device to another. There are several types of cable which are commonly used with LANs. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Understanding the characteristics of different types of cable and how they relate to other aspects of a network is necessary for the development of a successful network. Unshielded Twisted Pair (UTP) Cable Twisted pair cabling comes in two varieties: shielded and unshielded. Unshielded twisted pair (UTP) is the most popular and is generally the best option for school networks (See fig. 1). Fig.1. Unshielded twisted pair The quality of UTP may vary from telephone-grade wire to extremely high-speed cable. The cable has four pairs of wires inside the jacket. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices. The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot. The EIA/TIA (Electronic Industry Association/Telecommunication Industry Association) has established standards of UTP and rated five categories of wire.  Categories of Unshielded Twisted Pair Type Use Category 1 Voice Only (Telephone Wire) Category 2 Data to 4 Mbps (LocalTalk) Category 3 Data to 10 Mbps (Ethernet) Category 4 Data to 20 Mbps (16 Mbps Token Ring) Category 5 Data to 100 Mbps (Fast Ethernet) Buy the best cable you can afford; most schools purchase Category 3 or Category 5. If you are designing a 10 Mbps Ethernet network and are considering the cost savings of buying Category 3 wire instead of Category 5, remember that the Category 5 cable will provide more "room to grow" as transmission technologies increase. Both Category 3 and Category 5 UTP have a maximum segment length of 100 meters. In Florida, Category 5 cable is required for retrofit grants. 10BaseT refers to the specifications for unshielded twisted pair cable (Category 3, 4, or 5) carrying Ethernet signals. Category 6 is relatively new and is used for gigabit connections. Unshielded Twisted Pair Connector The standard connector for unshielded twisted pair cabling is an RJ-45 connector. This is a plastic connector that looks like a large telephone-style connector (See fig. 2). A slot allows the RJ-45 to be inserted only one way. RJ stands for Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. This standard designates which wire goes with each pin inside the connector.  Fig. 2. RJ-45 connector Shielded Twisted Pair (STP) Cable A disadvantage of UTP is that it may be susceptible to radio and electrical frequency interference. Shielded twisted pair (STP) is suitable for environments with electrical interference; however, the extra shielding can make the cables quite bulky. Shielded twisted pair is often used on networks using Token Ring topology. Coaxial Cable Coaxial cabling has a single copper conductor at its center. A plastic layer provides insulation between the center conductor and a braided metal shield (See fig. 3). The metal shield helps to block any outside interference from fluorescent lights, motors, and other computers. Fig. 3. Coaxial cable Although coaxial cabling is difficult to install, it is highly resistant to signal interference. In addition, it can support greater cable lengths between network devices than twisted pair cable. The two types of coaxial cabling are thick coaxial and thin coaxial. Thin coaxial cable is also referred to as thinnet. 10Base2 refers to the specifications for thin coaxial cable carrying Ethernet signals. The 2 refers to the approximate maximum segment length being 200 meters. In actual fact the maximum segment length is 185 meters. Thin coaxial cable is popular in school networks, especially linear bus networks.  Thick coaxial cable is also referred to as thicknet. 10Base5 refers to the specifications for thick coaxial cable carrying Ethernet signals. The 5 refers to the maximum segment length being 500 meters. Thick coaxial cable has an extra protective plastic cover that helps keep moisture away from the center conductor. Coaxial Cable Connectors The most common type of connector used with coaxial cables is the Bayone- Neill-Concelman (BNC) connector (See fig. 4). Different types of adapters are available for BNC connectors, including a T-connector, barrel connector, and terminator. Connectors on the cable are the weakest points in any network. To help avoid problems with your network, always use the BNC connectors that crimp, rather than screw, onto the cable. Fig. 4. BNC connector Ethernet Cable Summary Specification Cable Type Maximum length 10BaseT Unshielded Twisted Pair 100 meters 10Base2 Thin Coaxial 185 meters 10Base5 Thick Coaxial 500 meters 10BaseF Fiber Optic 2000 meters 100BaseT Unshielded Twisted Pair 100 meters  100BaseTX Unshielded Twisted Pair 220 meters   PRACTICAL - 7 AIM: - Configure an IP address on a workstation. How to assign/change the IP address that is assigned to a network adapter 1. Log on to the computer by using the Administrator account. 2. Click Start, click Settings, and then click Control Panel. 3. In Control Panel, double-click Network and Dial-up Connections. The Network and Dial-up Connections dialog box opens. 4. Right-click the local area connection that you want, and then click Properties. The Local Area Network Connection Properties dialog box opens. 5. In the Components checked are used by this connection box, click Internet Protocol (TCP/IP), and then click Properties. The Internet Protocol (TCP/IP) Properties dialog box appears. 6. Continue with the steps in one of the following two sections. 7. In the IP address box, type the IP address that you want to be assigned to this network adapter. This IP address must be a unique address in the range of addresses that are available for your network. Contact the network administrator to obtain a list of valid IP addresses for your network. 8. In the Subnet mask box, type the subnet mask for your network 9. In the Default gateway box, type the IP address of the computer or device on your network that connects your network to another network, or to the Internet. 10. In the Preferred DNS server box, type the IP address of the computer that resolves host names to IP addresses. 11. Click OK. In the Local Area Connection Properties dialog box, click OK. 12. Close the Network and Dial-up Connections window  PRACTICAL - 8 AIM: - Identify the IP address of a workstation and the class of the address. An IP address (Internet Protocol address) is a unique number that devices use in order to identify and communicate with each other on a computer network utilizing the Internet Protocol standard (IP). Any participating network device — including routers, computers, time-servers, printers, Internet fax machines, and some telephones — must have its own unique address. An IP address can also be thought of as the equivalent of a street address or a phone number (compare: VoIP) for a computer or other network device on the internet. Just as each street address and phone number uniquely identifies a building or telephone, an IP address can uniquely identify a specific computer or other network device on a network. An IP address can appear to be shared by multiple client devices either because they are part of a shared hosting web server environment or because a proxy server (e.g. an ISP or anonymizer service) acts as an intermediary agent on behalf of its customers, in which case the real originating IP addresses might be hidden from the server receiving a request. The analogy to telephone systems would be the use of predial numbers (proxy) and extensions (shared). IP addresses are managed by the Internet Assigned Numbers Authority. IANA generally assigns super-blocks to Regional Internet Registries, who in turn allocate smaller blocks to Internet Service Providers and enterprises. Dynamic and static IP addresses IP addresses may either be assigned permanently (for example, to a server which is always found at the same address) or temporarily from a pool of available addresses. Dynamic IP addresses are issued to identify non-permanent devices such as personal computers or clients. Internet Service Providers (ISPs) use dynamic allocation to assign addresses from a small pool to a larger number of customers. This is used for dial-up access, WiFi and other  temporary connections, allowing a portable computer user to automatically connect to a variety of services without needing to know the addressing details of each network. Users with a dynamic IP may have trouble running their own email server. In recent years services such as mail-abuse.org have collected lists of these address ranges and can be used as a block list. The most common protocol used to dynamically assign addresses is Dynamic Host Configuration Protocol (DHCP). DHCP includes a lease time which determines how long the requester can use an address before requesting its renewal, allowing addresses to be reclaimed if the requester goes offline. The DHCP server listens for requests and then assigns an address. System administrators may set the DHCP server so that it assigns addresses at random, or based on a predetermined policy. Once a machine receives its new IP address, it may tell that address to a Dynamic DNS server. Static IP addresses are used to identify semi-permanent devices with constant IP addresses. Servers typically use static IP addresses. The static address can be configured directly on the device or as part of a central DHCP configuration which associates the device's MAC address with a static address. An IP (Internet Protocol) address is a unique identifier for a node or host connection on an IP network. An IP address is a 32 bit binary number usually represented as 4 decimal values, each representing 8 bits, in the range 0 to 255 (known as octets) separated by decimal points. This is known as "dotted decimal" notation. Example: 126.96.36.199 Every IP address consists of two parts, one identifying the network and one identifying the node. The Class of the address and the subnet mask determine which part belongs to the network address and which part belongs to the node address.  Address Classes There are 5 different address classes. You can determine which class any IP address is in by examining the first 4 bits of the IP address. Class A addresses begin with 0xxx, or 1 to 126 decimal. Class B addresses begin with 10xx, or 128 to 191 decimal. Class C addresses begin with 110x, or 192 to 223 decimal. Class D addresses begin with 1110, or 224 to 239 decimal. Class E addresses begin with 1111, or 240 to 254 decimal. Addresses beginning with 01111111, or 127 decimal, are reserved for loopback and for internal testing on a local machine. [You can test this: you should always be able to ping 127.0.0.1, which points to yourself] Class D addresses are reserved for multicasting. Class E addresses are reserved for future use. They should not be used for host addresses. Now we can see how the Class determines, by default, which part of the IP address belongs to the network (N) and which part belongs to the node (n). Class A -- NNNNNNNN.nnnnnnnn.nnnnnnnn.nnnnnnnn Class B -- NNNNNNNN.NNNNNNNN.nnnnnnnn.nnnnnnnn Class C -- NNNNNNNN.NNNNNNNN.NNNNNNNN.nnnnnnnn In the example, 188.8.131.52 is a Class B address so by default the Network part of the address (also known as the Network Address) is defined by the first two octets (140.179.x.x) and the node part is defined by the last 2 octets (x.x.220.200). In order to specify the network address for a given IP address, the node section is set to all "0"s. In our example, 184.108.40.206 specifies the network address for 220.127.116.11. When the node section is set to all "1"s, it specifies a broadcast that is sent to all hosts on the network. 18.104.22.168 specifies the example broadcast address. Note that this is true regardless of the length of the node section.  PRACTICAL – 9 To make two kinds of cables used for connecting two or more computers The two most common unshielded twisted-pair (UTP) network standards are the10 Mhz 10BASE-T Ethernet and the 100Mhz 100BASE-TX Fast Ethernet. The 100BASE-TX standard is quickly becoming the predominant LAN standard. If you are starting from scratch, to build a small home or office network, this is clearly the standard you should choose. This article will show you how to make cables which will work with both standards. A LAN can be as simple as two computers, each having a network interface card (NIC) or network adapter and running network software, connected together with a crossover cable. The next step up would be a network consisting of three or more computers and a hub. Each of the computers is plugged into the hub with a straight-thru cable (the crossover function is performed by the hub). Let's start with simple pin-out diagrams of the two types of UTP Ethernet cables and watch how committees can make a can of worms out of them. Here are the diagrams:  Note that the TX (transmitter) pins are connected to corresponding RX (receiver) pins, plus to plus and minus to minus. And that you must use a crossover cable to connect units with identical interfaces. If you use a straight-through cable, one of the two units must, in effect, perform the cross-over function. Two wire color-code standards apply: EIA/TIA 568A and EIA/TIA 568B. The codes are commonly depicted with RJ-45 jacks as follows (the view is from the front of the jacks): If we apply the 568A color code and show all eight wires, our pin-out looks like this:  Note that pins 4, 5, 7, and 8 and the blue and brown pairs are not used in either standard. Quite contrary to what you may read elsewhere, these pins and wires are not used or required to implement 100BASE-TX duplexing--they are just plain wasted. However, the actual cables are not physically that simple. In the diagrams, the orange pair of wires are not adjacent. The blue pair is upside-down. The right ends match RJ-45 jacks and the left ends do not. If, for example, we invert the left side of the 568A "straight"-thru cable to match a 568A jack--put one 180° twist in the entire cable from end-to-end--and twist together and rearrange the appropriate pairs, we get the following can-of-worms: This further emphasizes, I hope, the importance of the word "twist" in making network cables which will work. You cannot use an flat-untwisted telephone cable for a network cable. Furthermore, you must use a pair of twisted wires to connect a set of transmitter pins to their corresponding receiver pins. You cannot use a wire from one pair and another wire from a different pair. Keeping the above principles in mind, we can simplify the diagram for a 568A straight-thru cable by untwisting the wires, except the 180° twist in the entire cable, and bending the ends upward. Likewise, if we exchange the green and orange pairs in the 568A diagram we will get a simplified diagram for a 568B straight-thru cable. If we cross the green and orange pairs in the 568A diagram we will arrive at a simplified diagram for a crossover cable. All three are shown below.    PRACTICAL - 10 AIM: - Sharing of resources with two connected nodes 1. Mapping a network drive Moving files between computers on a floppy disk (the so-called "sneakernet") is a thing of the past. If you have more than one computer in your home, you can share files across your home network. Shared folders from other computers appear in Windows Explorer just as if they were on the computer you're using. Sharing files is a two-step process: 1. Share a folder on the computer that stores your files. 2. Create a connection to the shared folder on the computer that you want to use to open the files. You can connect to the shared folder in two ways: (a) You can directly open the shared folder. This is the quickest way to get to your shared files. or (b) You can map a drive letter to the shared folder. This way makes it easier to open the folder in the future. The steps for both of these ways to connect to a shared folder on another computer on your home network are described below. Open a shared folder 1. On your desktop, double-click My Network Places. Note: If My Network Places is not on your desktop, click Start, and then click My Network Places on the Start menu.  2.In My Network Places, double-click the folder you want to open. You'll see your files in the folder.  Map a drive to a shared folder Click Start, and then click My Documents. Click the Tools menu, and then click Map Network Drive.  In the Map Network Drive dialog box, click Browse.  In the Browse For Folder dialog box, click the folder you want to connect to, and then click OK. In the Map Network Drive dialog box, make a note of the drive letter shown, and then click Finish.  If prompted, type your user name and password, and then click OK.  PRACTICAL - 11 Use of net stat and its switches netstat (=network statistics) is a command-line tool that displays a list of the active network connections the computer currently has, both incoming and outgoing. It is available on Unix, Unix-like, and Windows NT-based operating systems. On the Windows platform, netstat information can be retrieved by calling the GetTcpTable and GetUdpTable functions in the IP Helper API, or IPHLPAPI.DLL. Information returned includes local and remote IP addresses, local and remote ports, and (for GetTcpTable) TCP status codes. In addition to the command-line netstat.exe tool that ships with Windows, there are GUI-based netstat programs available Syntax netstat [-a] [-e] [-n] [-o] [-p Protocol] [-r] [-s] [Interval]  Windows: netstat /? Parameters -a : Displays all active TCP connections and the TCP and UDP ports on which the computer is listening. -b : Displays the binary (executable) program's name involved in creating each connection or listening port. -e : Displays extended statistics, such as the number of bytes and packets sent and received. This parameter can be combined with -s. -n : Displays active TCP connections, however, addresses and port numbers are expressed numerically and no attempt is made to determine names. -o : Displays active TCP connections and includes the process ID (PID) for each connection. You can find the application based on the PID on the Processes tab in Windows Task Manager. This parameter can be combined with -a, -n, and -p. This parameter is available on Microsoft Windows XP, 2003 Server (not Microsoft Windows 2000)). -p Protocol : Shows connections for the protocol specified by Protocol. In this case, the Protocol can be tcp, udp, tcpv6, or udpv6. If this parameter is used with -s to display statistics by protocol, Protocol can be tcp, udp, icmp, ip, tcpv6, udpv6, icmpv6, or ipv6. -r : Displays the contents of the [[IP routing table]]. This is equivalent to the route print command. -s : Displays statistics by protocol. By default, statistics are shown for the TCP, UDP, ICMP, and IP protocols. If the IPv6 protocol for Windows XP is installed, statistics are shown for the TCP over IPv6, UDP over IPv6, ICMPv6, and IPv6 protocols. The -p parameter can be used to specify a set of protocols. -v : When used in conjunction with -b it will display the sequence of components involved in creating the connection or listening port for all executables. Interval : Redisplays the selected information every Interval seconds. Press CTRL+C to stop the redisplay. If this parameter is omitted, netstat prints the selected information only once. /? : Displays help at the command prompt.