ITT Course – Unit I - Chapter 3

100 Hrs. Information Technology Training © IT Directorate, ICAI

Chapter-3 : Mobile Hardware and Networking Concepts

Learning Objective• Computer Hardware Setup • Networking of Computers• Mobile Hardware Devices• Use of mobile phones• Use of applets • Wireless Networks - Basic concepts.

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Introduction• Computers, Mobiles and Networking have been technology buzzwords

since the last 25 years. Computers and Mobiles have consistently reduced in size and increased in power. Interconnectivity is now instantaneous.

• Computers are now an integral part of business and home environments. Knowledge about their setup and configuration is essential for optimal usage. Mobile Phones are no less than computers with respect to features and information processing capabilities. The impact of Computers and Mobiles is augmented manifold when they are networked i.e. interconnected to each other. This networking or connectivity is achieved through a number of channels: Wired and Wireless networks, GSM and emerging technologies like NFC.

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Types of Computer


Desktop computers are designed for use at a desk or table. They are typically larger and more powerful than other types of personal computers. Desktop computers are made up of separate components. The main component, called the system unit, is usually a rectangular case that sits on or underneath a desk. Other components, such as the monitor, mouse, and keyboard, connect to the system unit.

Desktop Computers


Laptop computers are lightweight mobile PCs with a thin screen. They are often called notebook computers because of their small size. Laptops can operate on batteries, so you can take them anywhere. Unlike desktops, laptops combine the CPU, screen, and keyboard in a single case. The screen folds down onto the keyboard when not in use.

Laptop Computers


Handheld computers, also called personal digital assistants (PDAs), are battery-powered computers small enough to carry almost anywhere. Although not as powerful as desktops or laptops, handhelds are useful for scheduling appointments, storing addresses and phone numbers, and playing games. Some have more advanced capabilities, such as making telephone calls or accessing the Internet. Instead of keyboards, handhelds have touch screens that you use with your finger or a stylus (a pen-shaped pointing tool).

Handheld Computers


Tablet PCs are mobile PCs that combine features of laptops and handhelds. Like laptops, they're powerful and have a built-in screen. Like handhelds, they allow you to write notes or draw pictures on the screen, usually with a tablet pen instead of a stylus. They can also convert your handwriting into typed text. Some Tablet PCs are “convertibles” with a screen that swivels and unfolds to reveal a keyboard underneath.

Tablet PCs


Parts of Computers

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System Unit

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The system unit is the core of a computer system. Usually it's a rectangular box placed on or underneath your desk. Inside this box are many electronic components that process information. The most important of these components is the central processing unit (CPU), or microprocessor, which acts as the "brain" of your computer. Another component is random access memory (RAM), which temporarily stores information that the CPU uses while the computer is on. The information stored in RAM is erased when the computer is turned off. Almost every other part of your computer connects to the system unit using cables. The cables plug into specific ports (openings), typically on the back of the system unit. Hardware that is not part of the system unit is sometimes called a peripheral device or device.


Storage &Hard disk drive

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Storage:Your computer has one or more disk drives—devices that store information on a metal or plastic disk. The disk preserves the information even when your computer is turned off. Storage is also called secondary memory.

Hard disk drive:Your computer's hard disk drive stores information on a hard disk, a rigid platter or stack of platters with a magnetic surface. Because hard disks can hold massive amounts of information, they usually serve as your computer's primary means of storage, holding almost all of your programs and files. The hard disk drive is normally located inside the system unit.


CD and DVD drives

Nearly all computers today come equipped with a CD or DVD drive, usually located on the front of the system unit. CD drives use lasers to read (retrieve) data from a CD, and many CD drives can also write (record) data onto CDs. If you have a recordable disk drive, you can store copies of your files on blank CDs. You can also use a CD drive to play music CDs on your computer.

DVD drives can do everything that CD drives can, plus read DVDs. If you have a DVD drive, you can watch movies on your computer. Many DVD drives can record data onto blank DVDs.

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Mouse

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A mouse is a small device used to point and select items on your computer screen. Although mouse come in many shapes, the typical mouse does look a bit like an actual mouse. It's small, oblong, and connected to the system unit by a long wire that resembles a tail. Some newer mouse are wireless.

A mouse usually has two buttons: a primary button (usually the left button) and a secondary button. Many mice also have a wheel between the two buttons, which allows you to scroll smoothly through screens of information

When you move the mouse with your hand, a pointer on your screen moves in the same direction. (The pointer's appearance might change depending on where it's positioned on your screen.) When you want to select an item, you point to the item and then click (press and release) the primary button. Pointing and clicking with your mouse is the main way to interact with your computer. There are optical mouse which works on laser beam instead of roller ball.


KeyboardA keyboard is used mainly for typing text into your computer. Like the keyboard on a typewriter, it has keys for letters and numbers, but it also has special keys:

– The function keys, found on the top row, perform different functions depending on where they are used.

– The numeric keypad, located on the right side of most keyboards, allows you to enter numbers quickly.

– The navigation keys, such as the arrow keys, allow you to move your position within a document or webpage.

You can also use your keyboard to perform many of the same tasks you can perform with a mouse. 13


Monitor

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A monitor displays information in visual form, using text and graphics. The portion of the monitor that displays the information is called the screen. Like a television screen, a computer screen can show still or moving pictures. There are two basic types of monitors: CRT (cathode ray tube) monitors and LCD (liquid crystal display) monitors. Both types produce sharp images, but LCD monitors have the advantage of being much thinner and lighter. CRT monitors, however, are generally more affordable. LCD monitor (left); CRT monitor (right)


Printer

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A printer prints data from a computer onto paper. You don't need a printer to use your computer, but having one allows you to print e mail, cards, invitations, announcements, and ‑other materials. Many people also like being able to print their own photos at home. The two main types of printers are inkjet printers and laser printers. Inkjet printers are the most popular printers for the home. They can print in black and white or in full colour and can produce high-quality photographs when used with special paper. Laser printers are faster and generally better able to handle heavy use.

Fig: Inkjet printer (left); laser printer (right)


Modem

To connect your computer to the Internet, you need a modem. A modem is a device that sends and receives computer information over a telephone line or high-speed cable. Modems are sometimes built into the system unit, but higher-speed modems are usually separate components.

Modem Wireless Modem

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Network Interface cards(NIC)/ Ethernet cards• An Ethernet card is one kind of network adapter. These adapters support

the Ethernet standard for high-speed network connections via cables. Ethernet cards are sometimes known as network interface cards (NICs).

• Ethernet cards may operate at different network speeds depending on the protocol standard they support. Old Ethernet cards were capable only of the 10 Mbps maximum speed offered by Ethernet originally. Modern Ethernet adapters support the 100 Mbps Fast Ethernet standard and an increasing number now also offer Gigabit Ethernet support at 1 Gbps (1000 Mbps).

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Computer NetworksA computer network is an interconnected group of computers. Networks may be classified by the network layer at which they operate according to basic reference models considered as standards in the industry, such as the five-layer Internet Protocol Suite model (TCP 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).

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 for networks, these distinctions are more important to the network administrator than the user. Network administrators may have to tune the network, to correct delay issues and achieve the desired performance level.

By connection method, Computer networks can also 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 hubs, switches, bridges, gateways and/or routers.•Wireless LAN technology is built to connect devices without wiring. These devices use a radio frequency to connect

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By functional relationship (Network Architectures)Computer networks may be classified according to the functional relationships which exist between the elements of the network, e.g., 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.

Computer Network Continue…


Types of NetworksPersonal 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 6-9 meters). 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) and to connect to the internet.

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.


Types of Network Continue…

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

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Networks – Internet Protocol

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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:An intranet is a set of interconnected networks, using the Internet Protocol and uses IP-based tools such as web browsers and ftp tools, that is under the control of a single administrative entity. 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

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 is not considered to be a part of the intranet or extranet, although it may serve as a portal for access to portions of an extranet.


Mobile Hardware Devices have three main features, common to most them:•Mobile devices provide wireless communication to a base station (a personal computer, or a whole telephone, or data network)•Mobile devices must be small to be portable•Mobile devices must remain operational for several hours or days without a battery recharge.

Mobile Hardware Devices


SmartphonesSmartphones combine the functionality of Personal Digital Assistants(PDAs), wireless PCs, phones, and even digital cameras in one handset, making them a powerful business tool.Because greater functionality is built-in, smartphones can do things much more quickly than their standard mobile phone and PDA precursors

Benefits:Keeping you organisedFlexible working Information at your fingertips Never out of touchBetter information sharing Greater functionality Faster communication


Mobile devices need to be secure just like any other computing devices. But due to their transportable nature, some of the security techniques will be a bit different. It is recommend that you prepare for the possibility of a stolen, lost, damaged, or compromised device. The following methods can help you to recover from these problems and also aid you in preventing them from happening.Many mobile devices are not capable of providing strong security assurances to end users and organizations .

E.g.:1. Stolen and Lost Devices2. Compromised and Damaged Devices3. Selective Wipe

Mobile Security


Like other computers, mobile device architectures are composed of a stack of hardware, firmware, and software.

Mobile Device Architecture and Information classification

Device Owner & Information Owner A Device Owner is an entity that has purchased and maintains ownership of a mobile device. An Information Owner is an entity whose information is stored and/or processed on a device. An Information Owner can be an application-specific provider, a digital product provider, or an enterprise that allows access to resources from mobile devices, for example. Every mobile device has a single Device Owner and one or more Information Owners.


Mobile phones are used for a variety of purposes, including keeping in touch with family members/ friends, conducting business, and having access to a telephone in the event of an emergency. Some people carry more than one cell phone for different purposes, such as for business and personal use. Multiple SIM cards may also be used to take advantage of the benefits of different calling plans—a particular plan might provide cheaper local calls, long-distance calls, international calls, or roaming.

•General Usage•While driving•In schools•Mobile banking and payments•Two-way Interactive Text Messaging Applications•Tracking and privacy•Health effects•Environmental impact

Use of Mobile Phones


An applet is a software component that runs in the context of another program, for example a web browser. An applet usually performs a very narrow function that has no independent use. Hence, it is an application let.

An applet provides functionality or performance beyond the default capabilities of its container (the browser). At the same time, an applet’s capabilities are restricted by the container. An applet is written in a language that is different from the scripting or HTML language which invokes it.

Prior to the World Wide Web, the built-in writing and drawing programmes that came with Windows were sometimes called applets. On the Web, using Java language, an applet is a small programme that can be sent along with a Web page to a user. Java applets can perform interactive animations, immediate calculations, or other simple tasks without having to send a user request back to the server.

Use of Applets


Wireless networks utilize radio waves and/or microwaves to maintain communication channels between computers. Wireless networking is a more modern alternative to wired networking that relies on copper and/or fiber optic cabling between network devices.

Wireless is rapidly gaining in popularity for both home and business networking. Popular wireless local area networking (WLAN) products conform to the 802.11 "Wi-Fi" standards. Wireless networks are built using network adapters (NICs), access points (APs), and routers.

Different Types of Wireless Network Although we use the term wireless network loosely, there are in fact three different types of network. •Wide area networks that the cellular carriers create,•Wireless local area networks, that you create, and•Personal area networks, that create themselves.They all have a part to play in developing wireless solutions, separately or in various combinations. This section describes these different types of network, and explains where each can add value.

Basic Concepts & Types of Wireless Networks


Pros:• Mobility • Setup • Lack of mess Cons:• Speed• Reliability• Distance sensitive

Pros & Cons to a "Wireless" Network


Roaming among Wireless Local Area Networks

There are two definitions for wireless LAN roaming:

Internal Roaming: The Mobile Station (MS) moves from one access point (AP) to another AP within a home network because the signal strength is too weak. An authentication server (RADIUS) performs the re-authentication of MS via 802.1x.

External Roaming: The Mobile Station (client) moves into a WLAN of another Wireless Internet Service Provider (WISP) and takes their services (Hotspot). The user can independently of his home network use another foreign network, if this is open for visitors. There must be special authentication and billing systems for mobile services in a foreign network.


•Bluetooth signal can be considered to be narrowband, while Wi-Fi (802.11a/g), which is really many narrowband signals combined to create a much larger bandwidth signal to counteract the reflections or multi-path interference.

•Bluetooth technology is useful when transferring information between two or more devices that are near each other when speed is not an issue, such as telephones, printers, modems and headsets. It is best suited to low-bandwidth applications like transferring sound data with telephones (i.e. with a Bluetooth headset) or byte data with hand-held computers (transferring files) or keyboard and mice.

•Wi-Fi is better suited for operating full-scale networks because it enables a faster connection, better range from the base station, and better security (if configured properly) than Bluetooth.

•To connect a Bluetooth device to a mobile device, Bluetooth first needs to be enabled. Then the Bluetooth device needs to be synchronized to the mobile device. This is known as pairing or linking. It sometimes requires a pin code. When synchronized, the device needs to be connected. Finally, the Bluetooth connection should be tested. It can connect several devices, simultaneously.

Bluetooth and WiFi


•Infrared is shorter wavelength technology that requires a straight line of sight between source and target.•Bluetooth is a longer wavelength technology which also has the advantage of a radial range of sight between source and target.

Infrared and Bluetooth

RFID(Radio Frequency IdentificationRFID is the wireless non-contact use of radio-frequency electromagnetic fields to transfer data, for the purposes of automatically identifying and tracking tags attached to objects.

NFC(Near Field Communication

NFC is a set of standards for smartphones and similar devices to establish radio communication with each other by touching them together or bringing them into close proximity, usually no more than a few centimeters.


Connectivity Technologies•Wi-Fi Network Connectivity•Mobile Networking and Synchronization•GSM(Global System for Communications) Cellular Connectivity•1G•2G•2.5G•3G like WCDMA,EV-DO,HSPA•4G


Multiple Choice Questions1. Which is NOT a network topology

BusRingMeshBridge

2.PAN (Personal Area Networks) do NOT requireBluetoothInfraredEthernet CardsPrinters

3.Jailbreaking is used in the context of SmartphonesiOS devicesRooting EquipmentAndroid

4.‘Selective Wipe’ is generally used byOrganizationsIndividualsThievesJailbreakers


5.In which context does the Device manufacturer not operate?Hardware contextFirmware ContextApplication ContextOperating System Context

6.What is Zidisha?Mobile Operating SystemTelecom Service ProviderMicrolending PlatformMobile Manufacturer

7.WiFi is a common name for802.11802.11a802.11b802.11g

8.What is wardriving?Creating VirusesGuessing PasswordsUsing HotspotsSeeking Vulnerabilities in a Wireless LAN

Multiple Choice Questions Continue…


9.Which of the following require line-of-sight?Bluetooth InfraredGSMWi-Fi

10.What is ‘Internet Pass Through’Mobile Phone accessing Internet through PCPC accessing Internet through MobileMobile Phone using GPRSMobile Phone using bluetooth

Answers

Multiple Choice Questions Continue..

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ITT Course – Unit I - Chapter 3

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