Network Telecommunication Grade X Network Telecommunication Chapter 1

Network & Telecommunication Grade: X Network & Telecommunication (Chapter 1) limitless opportunities in learning info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Introduction Networking means the group of computer connected to each other through the communication media for the purpose of sharing the resources. The shared resources might be: • Data files • Applications • Hardware info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Advantages a) The copies of software can be copied with the other computers. b) Peripherals like printers, hard disk can be accessed by the computer in the network, so that total installation charge will be deducted. Disadvantages a) Highly chances of virus infection in the computers within the network. b) Highly chances of losing data/information, if proper authentication is not maintained. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Components of Computer Network To create the network between computers, some components are compulsorily needed. Some of the basic components of the network are: • Computer • Transmission media • Network software • Protocols info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Types of Network Computer network can be classified into different types depending upon its size, geographical distribution and the structure. The different types of computer network are: • Local Area Network (LAN) • Metropolitan Area Network (MAN) • Wide Area Network (WAN) info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Types of Network Local Area Network (LAN) A Local Area Network (LAN) is a network that is confined to a relatively small area. It is generally a limited to a geographic area such as a lab, school or building. Its main communications media are cables and generally owned by one organization. Data transmission rate is faster than WAN and less errors rates. Fig. Local Area Network Features (LAN): a) Owned by a single organizations. b) Diameter of not more than three kilometers (approx. ). info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Types of Network Metropolitan Area Network (MAN) A Metropolitan Area Network (MAN) covers larger geographical areas such as cities or school districts by interconnecting smaller networks within a large geographic area. Information is easily disseminated throughout the network. Features (MAN): Fig. Metropolitan Area Network a) A MAN, which can include one or more LANs as well as telecommunica tions equipment such as microwave and satellite relay stations, is smaller than a wide area network but generally operates at a higher speed. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Types of Network Wide Area Network (WAN) WAN stands for Wide Area Network, spans relatively large geographical area such as city to city, country to country and throughout the world. Its main communication media are satellite, telephone lines, radio modem etc. Fig. Wide Area Network Features (WAN): a) Owned by multiple organizations. b) Covers a large geographical area. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Topology The configuration or layout of a network formed by the connections between devices on a LAN (local area network) or between two or more LANs. • Bus Topology • Ring Topology • Star Topology info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Topology Bus Topology A topology (configuration) for a LAN (local area network) in which all nodes is connected to a main communications line (bus). Fig. Bus Topology Node: Each computer or device in a network is called a node. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Topology Bus Topology Advantages: a) It uses short length cable that decreases the installation cost. b) Low traffic cost. Disadvantages: a) If problem occurs on the bus, the entire network will go down. b) Limited to future addition of other devices. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Topology Ring Topology A LAN (local area network) in which devices (nodes) are connected in a closed loop, or ring. Fig. Ring Topology info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Topology Ring Topology Advantages: a) Short cable connections which cause an increase in network reliability. b) Supports optical fiber cable that is very high speed data transmission media. Disadvantages: a) Because of the closed loop, however, adding new nodes can be difficult. b) Any node failure causes network failure. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Topology Star Topology A LAN (local area network) in which each device (node) is connected to a central computer in a star shaped configuration (topology); commonly, a network consisting of a central computer (the hub) surrounded by terminals. Fig. Star Topology info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Topology Star Topology Advantages: a) Need only one link, i. e. input/output port. b) Easy to troubleshoot. Disadvantages: a) Long cable length, since each device is directly connected to the central hub. b) The entire network becomes inoperable if the central hub fails to work. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Topology LAN Configuration in Star Topology Fig. TCP/IP Properties info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Topology LAN Configuration in Star Topology DNS: Domain Name System Fig. IP Configuration DHCP: Dynamic Host Control Protocol info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Protocols The protocols are set of rules and formats for sending and receiving data. OR Protocols are technical guidelines that govern the exchange of signal transmission and reception between equipments. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Few Protocols Ø Hypertext Transfer Protocol (HTTP) is a communications protocol for the transfer of information on the Internet. Ø File Transfer Protocol (FTP) is a network protocol used to transfer data from one computer to another through a network, such as the Internet. Ø Simple Mail Transfer Protocol (SMTP) is a de facto standard for electronic mail (e mail) transmissions across the Internet. Ø Post Office Protocol version 3 (POP 3) is used to retrieve e mail from a remote mail server. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Few Protocols Ø Internet Protocol Suite (commonly TCP/IP) is the set of communications protocols used for the Internet and other similar networks. Ø IPX/SPX stands for Internetwork Packet Exchange/Sequenced Packet Exchange. IPX and SPX are networking protocols used primarily on networks using the Novell Net. Ware operating systems. Ø Address Resolution Protocol (ARP) is the method for finding a host's hardware address (MAC) when only its Network Layer address (IP) is known. MAC: Media Access Control IP: Internet Protocol RARP: Reverse Address Resolution Protocol info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Communication Devices Hub A hub is used in a wired network to connect Ethernet cables from a number of devices together. Fig. Hub info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Communication Devices Switch A switch is a device that channels incoming data from any of multiple input ports to the specific output port that will take the data toward its intended destination. Fig. Switch info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Communication Devices Router is a device (in some cases, software in a computer) connected to at least two networks and decides which way to send each information packet. Fig. Routers info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Communication Devices Repeaters A repeater is an electronic device that receives a signal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances without degradation. Fig. Repeaters info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Communication Devices MODEM (Modulator-Demodulator) Modem is a hardware, that directly converts digital signal from a computer or other digital devices into analog form for transmission over analog link (telephone line) and vice versa. Digital Analog = Modulation Analog Digital = Demodulation Fig. Internal Modem info@brushuponline. edu. np Brush-Up Online Fig. Cable Modem www. brushuponline. edu. np

Network & Telecommunication Communication Devices NIC (Network Interface Card) A network card, network adapter, LAN Adapter or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network. Fig. Network Interface Card info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Communication Devices Gateway A gateway is a network point that acts as an entrance to another network. A gateway is a combination of hardware and software that translates between two different protocols and acts as the connection point to the Internet. Fig. Gateway info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Data Communication Data communication refers to the process of transferring information from one location to another. Data communication Channels or Media The media through which information is transferred. Types of communication media a) Wired/Bounded/Guided Media b) Wireless/Unbounded/Unguided info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Wired/Bounded/Guided Media Co-axial Cable A single wire centered inside a shield, separated by a insulated material and covered by an insulating jacket. Fig. Co-axial Cables info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Wired/Bounded/Guided Media Twisted Pair Cable A type of communications transmission cable in which two individually insulated wires are twisted around each other to reduce induction and crosstalk from one wire to the other. The pair may be surrounded by a shield, insulating jacket or additional pairs of wires. Fig. UTP (Unshielded Twisted Pair) info@brushuponline. edu. np Brush-Up Online Fig. STP (Shielded Twisted Pair) www. brushuponline. edu. np

Network & Telecommunication Wired/Bounded/Guided Media Fiber Optic Cable A transmission medium that uses glass or plastic fibers, rather than copper wire, to transport data or voice signals. Fig. Fiber Optic Cables info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Wireless/Unbounded/Unguided Media Wireless Technology Wireless technology provides the ability to communicate between two or more entities over distances without the use of wires or cables of any sort. This includes communications using radio frequency (RF) as well as infrared (IR) waves. a) b) c) d) e) Infrared ray X-ray Ultra-violet ray Microwave Radio wave Fig. Microwave relay towers for cellular telephone info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Wireless/Unbounded/Unguided Media Fig. Wireless LAN info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Media Connectors BNC Connector (Co-axial Cable) ST Connector (Fiber Optic Cable) info@brushuponline. edu. np RJ-45 (Twisted Pair Cable) Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Software Network Operating System (NOS) The software that controls the operation of the network. A NOS enables users to communicate and to share files and peripherals. v v v info@brushuponline. edu. np Novell Net. Ware Linux Windows Server NT/2003/2008 Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Software Client Operating System The control program in a user's machine (desktop or laptop). Macintosh OS Leopard Windows XP Windows Vista v v v Fig. Mac OS Leopard info@brushuponline. edu. np Fig. Windows XP Brush-Up Online Fig. Windows Vista www. brushuponline. edu. np

Network & Telecommunication Data Transmission Modes There are three ways for transmitting data from one point to another. a) Simplex In simplex mode the communication can take place in one direction. The receiver receives the signal from the transmitting device. In this mode the flow of information is Uni. -directional. Hence it is rarely used for data communication. Example: An example is a traditional television broadcast. The signal is sent from the transmitter to TV antenna. There is no return signal. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Data Transmission Modes b) Half-duplex In half-duplex mode, data can flow in both directions but not at the same time. It is transmitted one-way at one time. A device with half-duplex mode can send or receive data but not at the same tune. That is why the speed of half-duplex mode is slow. Example: Internet surfing is an example of half-duplex communication. The user issues a request for a web page. The web page is downloaded and displayed before user issues other request. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Data Transmission Modes c) Full-duplex In full-duplex mode, data can travel in both directions simultaneously. Full duplex mode is a faster way of data transmission as compared to half duplex. Time is not wasted in changing the direction of data flow. Example: A telephone is a full duplex device. Both persons can talk at the same time. Another example of full-duplex communication is automobile traffic on a two-lane road. The traffic can move in both directions at the same time. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Data Transmission Speed Bandwidth In computer networks, bandwidth is often used as a synonym for data transfer rate - the amount of data that can be carried from one point to another in a given time period (usually a second). This kind of bandwidth is usually expressed in bits (of data) per second (bps). Occasionally, it's expressed as bytes per second (Bps). A modem that works at 57, 600 bps has twice the bandwidth of a modem that works at 28, 800 bps. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Binary confusion: kilobytes and kibibytes bps Bytes per second Kbps Kilobits per second KBps Kilobytes per second Mbps Kilobytes (KB) 1. 000 Kibibyte (Ki. B) 1024 Megabyte (MB) 1. 000 ^ 2 Mebibyte (Mi. B) 1024 ^ 2 Megabits per second Gigabyte (GB) 1. 000 ^ 3 Gibibyte (Gi. B) 1024 ^ 3 MBps Megabytes per second Terabyte (TB) 1. 000 ^ 4 Tebibyte (Ti. B) 1024 ^ 4 Gbps Gigabits per second GBps Gigabytes per second Petabyte (PB) 1. 000 ^ 5 Pebibyte (Pi. B) 1024 ^ 5 Remember 1 Kbps = 1000 bits per second info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Architecture Peer-to-peer Network Ø Sometimes called a workgroups. Ø All the computers on the network have equal responsibilities. Ø Nonhierarchical relation. Ø Easy to setup. Ø Difficult to maintain security and authentication. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Advantages of peer-to-peer network Ø Less initial expense - No need for a dedicated server. Ø Setup - An operating system (such as Windows XP) already in place may only need to be reconfigured for peer-to-peer operations. Disadvantages of peer-to-peer network Ø Decentralized - No central repository for files and applications. Ø Security - Does not provide the security available on a client/server network. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Architecture Client-Server Network Ø Sometimes called a domain. Ø At least one server to administer the whole network. Ø Hierarchical relation. Ø Provides high level security and authentication. Ø Different server: DNS Server, DHCP Server, WINS Server, Web Server, Mail Server etc. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Advantages of client-server network Ø Ø Ø Centralized - Resources and data security are controlled through the server. Scalability - Any or all elements can be replaced individually as needs increase. Flexibility - New technology can be easily integrated into system. Interoperability - All components (client/network/server) work together. Accessibility - Server can be accessed remotely and across multiple platforms. Disadvantages of client-server network Ø Expense - Requires initial investment in dedicated server. Ø Maintenance - Large networks will require a staff to ensure efficient operation. Ø Dependence - When server goes down, operations will cease across the network. info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Network Servers Fig. Servers info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Web Servers Fig. Web Servers info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np

Network & Telecommunication Question and Answer Session info@brushuponline. edu. np Brush-Up Online www. brushuponline. edu. np