Seminar Report[Networking]

A TECHNICAL SEMINAR REPORT

on

INTRODUCTION TO NETWORKING

Submitted in partial fulfillment of the requirement

For the award of the degree of Bachelor of Technology

in

Computer Science & Engineering

Submitted to: Submitted by:

Er. Rakesh Rana Jyoti Kumari

Lecturer 3910045

(CSE Department) CSE(5th sem)

DEPARTMENT OF COMPUTER SCIENCE & ENGINEERING

MODERN INSTITUTE OF ENGINEERING & TECHNOLOGY

(Affiliated To Kurukshetra University, Kurukshetra, Haryana, India)

CONTENTS

1. Abstract 2. Introduction to computer networking3. Need of computer network4. Networking models

4.1. Centralized4.2. Distributed4.3. Collaborative

5. Type of computer networks5.1. LAN 5.2. WAN5.3. MAN

6. Components of network6.1. Network services

6.1.1. File services6.1.2. Print services6.1.3. Message services6.1.4. Application services6.1.5. Database services

6.2. Transmission media6.2.1. Guided Media

6.2.1.1. Twisted pair 6.2.1.1.1. Shielded twisted pair6.2.1.1.2. Unshielded twisted pair

6.2.1.2. Coaxial6.2.1.3. Fiber optic

6.2.1.3.1. Single mode6.2.1.3.2. Multimode

6.2.2. Unguided Media6.2.2.1. Radio wave6.2.2.2. Microwave6.2.2.3. Infrared

6.3. Protocols7. Data Transmission modes

7.1. Simplex7.2. Half duplex7.3. Full duplex

8. Connectors8.1. RJ118.2. RJ458.3. BNC

9. Cables9.1. Straight cable9.2. Crossover cable9.3. Rolled over cable

10. Network devices10.1. NIC10.2. Hubs10.3. Switches10.4. Repeaters10.5. Multiplexer10.6. MODEM10.7. Routers10.8. Bridges10.9. Brouters10.10. Gateway

1. ABSTRACT

Computer networks have become increasingly ubiquitous. The rapid proliferation of Computer networks has changed the landscape of 21th century. In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software.

The applications like e-mail, web-browsing, digital library, audio-video conferencing, video on demand, e-commerce, file transfer, Wi-Fi, remote desktop assistance, cloud computing, digital signatures, social networking sites and many more has forced people to use networking. Through networking people can take advantage of these applications. Therefore networking is the concept of sharing resources and services.

As we can no longer imagine our life without computers. Today they are an integral part of our homes and offices. The Internet, employing computer networking at its best, has brought the world at our fingertips. There is better storage and collaboration of information and communication is faster. Not only individuals, but entire economies have been empowered to function efficiently, making our lives easier and more streamlined. Here, we welcome you to explore and learn more about computer networking.

2. INTRODUCTION TO COMPUTER NETWORKING

Computer networking is the interconnection of two or more computers. We connect several computers at different locations to exchange information or do other works in a shared or mutually accessible data base i.e. Computer networking is the establishment or use of Computer Network.

Computer network is a group of computer and other peripheral devices, connected by communication lines (cables or other channels), which are capable of sharing files and other resources between several users. The communication lines connecting the devices are often called communication channels or transmission media. The performance of the network depends on no. of users, type of transmission medium, hardware, and software.

Computer network

3. NEED OF COMPUTER NETWORK

Need of computer network arose due to these reasons:

Resource sharing: All computers in the network can share resources such as printers, fax machines, modems, and scanners.

Cost Reduction: Cost can be reduced by sharing resources (devices) in the network.

Flexible Access: Networks allow their users to access files from computers throughout the network. This means that a user can begin work on a project on one computer and finish up on another. Multiple users can also collaborate on the same project through the network.

File Sharing: Networks offer a quick and easy way to share files directly. Instead of using a disk or USB key to carry files from one computer or office to another, you can share files directly using a network.

Communication: Even outside of the internet, those on the network can communicate with each other via electronic mail over the network system. When connected to the internet, network users can communicate with people around the world via the network.

Security: Specific directories can be password protected to limit access to authorized users.

Error Reduction and Improve Consistency: One can reduce errors and improve consistency by having all staff work from a single source of information, so that standard versions of manuals and directories can be made available, and data can be backed up from a single point on a scheduled basis, ensuring consistency.

4. NETWORKING MODELS

There are several different models of how computers work together in a network. Three general models are:

4.1 Centralized: Centralized computing centers around large host computers. These hosts are generally mainframe handles all the data storage and data processing. The dumb terminals are connected to them normally acts as input/output devices, since they have little or no processing power. They are expensive but they provide centralized administration. The dumb terminal, the user could run programs, access resources, and copy files as all the processing took place in one central location.

4.2 Distributed: The distributed models of computing involve a network of intelligent computers, called client, which are able to share the processing load. Each client can process its own task, some data is actually stored and processed at the client end and services are requested and provided by the server. We can even categorize this model of networking as:

Client/Server Peer to Peer

In Client/Server environment client depends upon server for sharing of resources, services and security only. Else everything processed at a client end. Generally this type of computing used in big to very big networks.

In a Peer-to-Peer environment all computers have a similar storage and processing power. They are used in very small and friendly environment where security issue not considered. All system acts as client all act as server.

4.3 Collaborative: collaborative computing is a combination of computers working together processing the same task. A computer might run a part of program on another computer in order to maximize processing power. It is extension of distributed computing model. Like distributed computing, it involves clients with internal processing power that can share data and services.

5. TYPES OF COMPUTER NETWORK

The types of network are categorized on the basis of the number of systems or devices that are under the networked area. In order to be proficient in network security, you have to understand the different types of networks since each network type poses different challenges, issues and risks.

5.1 LAN: A Local Area Network (LAN) is a relatively small network that is confined to a small geographic area, such as a single office or a building. Laptops, desktops, servers, printers, and other networked devices that make up a LAN are located relatively close to each other. From a security context, LANs are the point at which trusted users typically access your network and server resources. The maximum speed of a LAN can be 1000 megabits per second. LANs tend to have fewer problems associated with them, as there are a smaller amount of systems to deal with.

5.2 WAN: A Wide Area Network (WAN) covers a significantly larger geographic area than LANs or MANs. A WAN uses public networks, telephone lines, and leased lines to tie together smaller networks such as LANs and MANs over a geographically dispersed area. Connecting devices in different geographic areas together for information sharing, WANs are an important piece of enterprise networks. The best example of a WAN could be the Internet that is the largest network in the world. The maximum speed of a WAN can be 150 megabits per second. A WAN is usually slower because it has lower bandwidth. WANs tend to be fewer faults tolerant. As it consists of a large amount of systems there is a lower amount of fault tolerance.

5.3 MAN: The term Metropolitan Area Network (MAN) is typically used to describe a network that spans a citywide area or a town. MANs are larger than traditional LANs and predominantly use high-speed media, such as fiber optic cable, for their backbones. MANs are common in organizations that need to connect several smaller facilities together for information sharing. This is often the case for hospitals that need to connect treatment facilities, outpatient facilities, doctor's offices, labs, and research offices for access to centralized patient and treatment information. MANs share many of the same security threats as LANs, but on a larger scale. The maximum speed of a MAN can be 80 megabits per second.

6. COMPONENTS OF NETWORK

Every network needs to have certain components in order to work properly. The required components are:

6.1 Network services: such as printing, e-mail, file sharing exchanged between service requesters, and service providers.

6.1.1 File services: File service enables networked computers to share files. Some key file services include file transfer, file storage, data migration, file updating. All files are stored on single server from where other host request files. It can be easily managed and the cost is also distributed between many users.

6.1.2 Print services: Printing is the second incentive of installing a LAN. Many users can share same printer. Printer can be located anywhere, not just next to user’s PC. Queue based network printing is also supported that make service more efficient.

6.1.3 Message services: Message services include variety of communication methods that go far beyond simple file services. With message services, data can take the form of graphics, digitized video, and audio as well as text and binary data. The main types of message services are e-mail, directory services.

6.1.4 Application services: Application services enables applications to leverage the computing power and specialized capabilities of other computers on a network. For example one application is installed with licensed key and other users in LAN can use it with no additional cost.

6.1.5 Database services: Database services enable applications to be designed in separate client and server components, such applications are frequently called client/server databases.

6.2 Transmission media: They are the physical or wireless pathways that connect PCs or other devices. Transmission media can be broadly classified into 2 broad categories:

6.2.1 Guided media: Guided media, which are those that provide a conduct from one device to another, include twisted-pair, coaxial and fiber optic. A signal traveling along any of these media is directed and is contained by the physical limits of the medium.

6.2.1.1 Twisted pair: Twisted pair cable is the cheaper and oldest form of transmission medium which is used today. In this type of line a pair of insulated wires is twisted together. They are insulated from each other. One is used for signal and other is used for ground reference. It reduces crosstalk. They are suitable for bit rates of the order of 1 Mbps over short distances. They are most commonly used in connections of stars and hub networks.

6.2.1.1.1 Shielded Twisted Pair: Often abbreviated as STP, a type of copper telephone wiring in which each of the two copper wires that are twisted together are coated with an insulating coating that functions as a ground for the wires. The extra covering in shielded twisted pair wiring protects the transmission line from electromagnetic interference leaking into or out of the cable. STP cabling often is used in Ethernet networks, especially fast data rate Ethernets.

6.2.1.1.2 Unshielded Twisted Pair: Often abbreviated as UTP, a popular type of cable that consists of two unshielded wires twisted around each other. Due to its low cost, UTP cabling is used extensively for local area network (LANs) and telephone connections. UTP cabling does not offer as high bandwidth or as good protection from interference as coaxial or fiber optic cables, but it is less expensive and easier to work with. UTP is the most common form of twisted pair wiring, because it is less expensive and easier to work with than STP.

6.2.1.2 Coaxial: Coaxial cable, or coax, is an electrical cable with an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. Coaxial cable is one of the most important kinds of transmission media used in LANs. The major problems of higher attenuation and signal power lost at high frequencies of twisted pair cables were minimized by using coaxial cable. In this the signal and ground reference wires run concentrically inside a solid outer circular conductor. The space between two conductors is filled with dielectric insulating material with a honey comb structure. The skin effect and power losses were minimized by these cables.

6.2.1.3 Fiber optic: An optical fiber is a thin, flexible, transparent fiber that acts as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. Optical fibers are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communication.6.2.1.3.1 Single mode: Single mode fiber refers to the fact that

only a single wavelength (one color of light) is transmitted over the physical medium. It is true doped

fiberglass fibers wrapped in a plastic cladding. Single mode typically has much longer reach, but a larger bend radius than multi-mode.

6.2.1.3.2 Multimode: Multimode fiber can carry multiple wavelengths, is made of special clear plastic material and has a much smaller bend radius that single mode fiber. It does not have as long a reach as single mode fiber.

6.2.2 Unguided Media: Unguided media transport electromagnetic waves without using a physical conductor. This type of communication is often referred to as wireless communication. Signals are normally broadcast through the air and thus are available to any one who has the device capable of receiving them.6.2.2.1 Radio wave: Radio waves are Omni-directional. When an antenna

transmits radio waves, they are propagated in all directions. This means that the sending and receiving antennas do not have to be aligned. A sending antenna sends waves that can be receiving by any receiving antenna. Radio is most famously utilized to send audio, images, and text in the form of signals. Radio waves are used for multicast communications, such as radio and television, and paging systems.

6.2.2.2 Microwave: Microwaves are unidirectional. When an antenna transmits microwave waves, they can be narrowly focused. The sending and receiving antennas need to be aligned. Microwave system uses very high frequency radio signal to transmit data through space. Microwaves are used for unicast communication such as cellular phones, satellite networks, and wireless LANs.

6.2.2.3 Infrared: Infrared waves, with frequencies from 300 GHz to 400 THz, can be used for short-range communication. Infrared waves, having high frequencies, cannot penetrate walls. This advantage characteristic prevents interface between one system and another; a short-range communication system in one room cannot be affected by another system in the next room. Used for very short line sight transmission, remote car locking systems, wireless security alarms, TV remote.

6.3 Protocols: A protocol is a set of rules that governs the communications between computers on a network. The key elements of a protocol are syntax, semantics, and timing. Eg. FTP, SMTP, TCP/IP, ARP, UDP, HTTP, DHCP etc.

7. DATA TRANSMISSION MODES

A given transmission on a communication channel between two machines can occur in several ways. The transmission is characterized by the direction of the exchanges, no. of bits sent simultaneously, synchronization between sender and receiver.

7.1 Simplex: A simplex connection is a connection in which the data flows in only one direction, from the transmitter to the receiver. This type of connection is useful if the data do not need to flow in both directions. For example, from your computer to the printer or from the mouse to your computer.

7.2 Half duplex: A half-duplex connection is a connection in which the data flows in both directions, but not both at the same time. With this type of connection, each end of the connection transmits in turn. For example, walkie-talkie.

7.3 Full duplex: A connection is a connection in which the data flow in both directions simultaneously. Each end of the line can thus transmit and receive at the same time, which means that the bandwidth is divided in two for each direction of data transmission. For example, telephone, mobile.

8. CONNECTORS

A connector is best known for providing a physical link between two components.

8.1 RJ11: Registered jack (RJ) is a standardized physical network interface.RJ11 is more commonly known as a phone connector, phone jack or phone line, the RJ-11 is short for Registered Jack-11 and is a four or six wire connection primarily used for telephones and computer modem connectors.

8.2 RJ45: Short for Registered Jack-45, a RJ-45 is a 8-pinconnection used for Ethernet network adapters. This connector resembles to the RJ-11 or 6-pin connector used with telephones, but they're completely different. On the connector are eight contacts corresponding to the eight wires in the cable, and these match the eight contacts of the RJ-45 port on your computer or network device. Local Area Networks (LAN) use Ethernet cables and RJ-45 connectors to connect two or more computers on the same network. Ethernet cables are plugged into a hub, router or switch to make up the LAN.

8.3 BNC: Short for Bayonet Neill Concelman connector, a BNC connector is a type of connector used with coaxial Ethernet cable. The connector is bayonet-style, meaning that it is put in then turned and locked in position. This connector is commonly used on a Token Ring network. BNC is also short for Bayonet Nut Connector or British Naval/Navy Connector although more appropriately known as the Bayonet Neill Concelman.

9. CABLES

Cables are used to connect one network device to other network devices or to connect two or more computers to share printer, scanner, router etc.

9.1 Straight cable: Straight cable is use to connect different type of devices. This type of cable will be used most of the time and can be used to connect a computer to a switch/hub's normal port, connect a computer to a cable/DSL modem's LAN port, connect a router's WAN port to a cable/DSL modem's LAN port, and connect a router's LAN port to a switch/hub's uplink port, connect 2 switches/hubs with one of the switch/hub using an uplink port and the other one using normal port.

9.2 Crossover cable: Crossover cable usually used to connect same type of devices. A crossover cable can be used to connect 2 computers directly, connect a router's LAN port to a switch/hub's normal port, and connect 2 switches/hubs by using normal port in both switches/hubs.

9.3 Rolled over cable: Rollover cable also known as Cisco console cable or a Yost cable is a type of null-modem cable that is often used to connect a computer terminal to a router's console port. This cable is typically flat (and has a light blue color) to help distinguish it from other types of network cabling. It gets the name rollover because the pin outs on one end are reversed from the other, as if the wire had been rolled over and you were viewing it from the other side.

10 NETWORK DEVICES

10.1 NIC: A network interface card more commonly referred to as a NIC, is a device that allows computers to be joined together in a LAN, or local area network. Networked computers communicate with each other using a given protocol or agreed-upon language for transmitting data packets between the different machines, known as nodes. The network interface card acts as the liaison for the machine to both send and receive data on the LAN.A network interface card (NIC) is basically a computer circuit board or card that is installed in a computer so that it can be connected to a network.

10.2 Hubs: Connects all computers in a network to each other and helps direct messages to appropriate recipients; as more users join the network, more hubs may be added. The hub is a central connection point for wiring the network. A typical hub has multiple ports to which computers and peripheral devices such as servers are attached. The hub receives, re-times and regenerates signals received from any attached station. The hub also functions as a filter i.e. it discards severely distorted frames.

10.3 Switches: A concentrator is a device that provides a central connection point for cables from workstations, servers, and peripherals. It Provide packet filtering between the LANs. Increase network performance by providing each port

with dedicated bandwidth without requiring users to change any existing equipment, such as NICs, hubs, wiring, or any routers or bridges that are currently in place. Switches can also support numerous transmissions simultaneously.

10.4 Repeaters: When a signal travels along a cable, it tends to lose strength. A repeater is a device that boosts a network's signal as it passes through. The repeater does this by electrically amplifying the signal it receives and re-broadcasting it. Repeaters can be separate devices or they can be incorporated into a concentrator. They are used when the total length of the network cable exceeds the standards set for the type of cable being used.

10.5 Multiplexer: A multiplexer (or MUX) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line and the process is known as multiplexing.

10.6 MODEM: A modem (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a

carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. The most familiar example is a voice band modem that turns the digital data of a personal computer into modulated electrical signals in the voice frequency range of a telephone channel. These signals can be transmitted over telephone lines and demodulated by another modem at the receiver side to recover the digital data.

10.7 Routers: The difference between a router and a bridge is that a router operates at level 3 in the OSI seven layer model, whereas a bridge operates at level 2. This means that a router can be used to connect different types of networks and, because it has access to level 3 routing information, can dynamically make the best (cheapest, fastest, etc) choice of route between the networks. Routers divide the network logically instead of physically. A router will decide whether to forward a packet by looking at the protocol level addresses (e.g. TCP/IP addresses) rather than MAC address.

10.8 Bridges: A bridge will connect to distinct segments (usually referring to a physical length of wire) and transmit traffic between them. A bridge therefore serves two purposes. It connects two similar networks. For example, if two LANs are connected with a bridge, the users of each LAN can access the other network’s file server without making any physical changes to their data. A bridge allows segmentation of large networks into two smaller, more efficient networks.

10.9 Brouters: A bridge router or brouter is a network device that works as a bridge and as a router. The brouter routes packets for known protocols and simply forwards all other packets as a bridge would. Brouters operate at both the network layer for routable protocols and at the data link layer for non-routable protocols.

10.10 Gateways: A gateway is a network point that acts as an entrance to another network. A gateway may contain devices such as protocol translators, impedance matching devices, rate converters, fault isolators, or signal translators as necessary to provide system interoperability. It also requires the establishment of mutually acceptable administrative procedures between both networks.