1. Chapter 1 Basics of Networking & Designs of Simple Networks powered by DJ

2. C HAPTER O BJECTIVES - At the end of this Chapter you will be able to:  Understand Computer networking concepts.  Describe the purpose and functions of various network devices.  Select the components required to meet a network specification. powered by DJ

3. What is a Network? In general, the term network can refer to any interconnected group or system. More specifically, a network is any method of sharing information between two systems (human, electrical or mechanical). Introduction to Computer Networking Concepts Figure 1: A Simple Network Example powered by DJ

4. Classification of Network 1. According to the size of the Network:  LAN  MAN  WAN  PAN  CAN 2. According to type of connection used:  Wired Network  Wireless Network powered by DJ

5. 3. According to the functional relationship(Network Architecture):  Peer to Peer Network  Client Server Network powered by DJ

6. According to the Size of the Network LAN (Local Area Network)  A Local Area Network is a group of computers and network communication devices within a limited geographic area, such as an office building. For example, a library will have a wired or wireless LAN for users to interconnect local devices(e.g., printers, and servers).  Local area networking uses switches, bridges and/or repeaters, and hubs to interconnect LANs and increase overall size. Routers are used to connect a LAN to a WAN or MAN. powered by DJ

7. Figure 2: A Simple LAN Illustration They are characterized by the following:  High data transfer speeds.  Generally less expensive technologies  Limited geographic area  Security  Scalability  Reliability powered by DJ

8. MAN (Metropolitan Area Network) WAN (Wide Area Network) A WAN is a data communications network that covers a relatively broad geographic area (i.e. one country to another country) and that often uses transmission facilities provided by common carriers, such as telephone companies. They are generally connected with each other using routers. 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. A MAN can range anywhere from 5 to 50km in diameter. powered by DJ

9. They are characterized by the following:  Multiple interconnected LANs.  Generally more expensive technology.  More sophisticated to implement than LANs.  Exist in an unlimited geographic area. Figure 3: An Example of WAN powered by DJ

10. Personal Area Network (PAN) Storage Area Network (SAN)  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,scanners.The reach of a PAN is typically within about 20-30 feet (approximately 6-9 Meters).  We have a lot of data in the form of audio and video. We need to store data for quick access and transfer on special storage devices.  SAN may be referred to as a sub network or special purpose network. Its special purpose is to allow users on a larger network to connect various data storage devices with clusters of data servers. powered by DJ

11. Virtual Private Network (VPN)  VPN is a private network that lets you access public networks remotely.  VPN uses encryption and security protocols to retain privacy while it accesses outside resources by creating a virtual network. powered by DJ

12. According To the Type of Connection Used  Wired Network: A network that connects devices using cables (wires) like Coaxial Cable, Twisted pair Cable, Optical Fiber Cable etc.  Wireless Network: A network that connects devices using wireless technologies like Bluetooth, infrared, radio frequency etc. powered by DJ

13. According To the Functional Relationship (Network Architecture) Peer to peer network (Workgroup)  A workgroup is a collection of computers on a LAN that share common resources and responsibilities.  Workgroups provide easy sharing of files, printers and other network resources. Client-Server Network (Domain)  A Domain is a “Network Architecture” in which each computer or process on the network is either a client or a server.  servers are powerful computers or processes dedicated to managing disk drives (file servers), printers (print servers) etc.  Clients are PCs or workstations on which users run applications.  Clients rely on servers for resources, such as files, devices, and even processing power. powered by DJ

14. Network Topologies Topology refers to the way in which the network of computers is connected. The choice of topology is dependent upon---  Type and number of equipment being used  Planned applications and rate of data transfers  Required response times  Cost Types of Network Topologies  Physical Topology: Physical topology defines how devices are connected to the network through the actual cables that transmit data(physical structure of the network)  Logical Topology: Logical Topology (also referred to as Signal Topology) is a network computing term used to describe the arrangement of devices on a network and how they communicate with one another. powered by DJ

15. 1. BUS Topology Figure 4: Bus Topology Representation In a BUS topology:  A single cable connects each workstation in a linear, daisy- chained fashion.  Signals are broadcasted to all stations, but stations only act on the frames addressed to them. powered by DJ

16. 2. RING Topology Figure 5: Ring Topology Representation In a RING topology:  Unidirectional links connect the transmit side of one device to the receive side of another device.  Devices transmit frames to the next device (downstream member) in the ring. powered by DJ

17. 3. STAR Topology Figure 6: Star Topology Representation In a star topology:  Each station is connected to a central Hub or Switch (concentrator) that functions as a multi-port repeater.  The HUB broadcasts data all of the devices connected to it.  The Switch transmits the data to the dedicated device for which the data is meant for. powered by DJ

18. Basic Networking Devices 1. Network Interface Cards A Network Interface Card (NIC) 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. powered by DJ

19. 2. Repeaters Examples of Repeater A repeater is an electronic device that receives a signal and retransmits it at a higher level or higher power powered by DJ

20. 3. HUBS Example of Hubs A hub (concentrator) contains multiple ports, which is used to connect devices in a star topology. When a packet arrives at one port, it is copied to all the ports of the hub. But when the packets are copied, the destination address in the frame does not change to a broadcast address powered by DJ

21. 4. Bridges A Common Bridge 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 learn which physical addresses are reachable through specific ports powered by DJ

22. 5. Switches Switches  A switch is a device that performs switching. Specifically, it forwards and filters OSI layer 2 datagram (chunk of data communication) between ports (connected cables) based on the Physical-Addresses in the packets  A switch normally has numerous ports than Bridge. powered by DJ

23. 6. Routers Two Modern Routers Routers are networking devices that forward data packets along networks by using headers and forwarding/routing tables to determine the best path to forward the packets. Routers work at the Internet Layer of the TCP/IP model or layer 3 of the OSI model powered by DJ

24. WAN Infrastructure Devices As with LAN, there are numerous devices associated with data transmission across a WAN. Together these devices create the infrastructure of a functional WAN. These devices include:  Router  ATM Switch  Modem and CSU/DSU  Communication Server  Multiplexer powered by DJ

25. ATM Switch ATM Switches provide high-speed transfer between both LANs and WANs ATM Switch in the middle powered by DJ

26. Modem (modulator / demodulator) Modems convert digital and analog signals. At the source, modems convert digital signals to a form suitable for transmission over analog communication facilities (public telephone lines). At the destination, modems convert the signal back to a digital format. An Early Modem powered by DJ

27. Multiplexer A Multiplexer combines multiple signals for transmission over a single circuit. This allows for the transfer of various data simultaneously, such as video, sound, text, etc. Multiplexing powered by DJ

28. Communication Servers Communication Servers are typically dial-in/out servers that allow users to dial in from remote locations and attach to the LAN. Dial-up Communications powered by DJ

29. THANK YOU powered by DJ