11NETWORKINGTECHNOLOGIESBUS3500 - Abdou Illia, Fall 2012(October 15, 2012)2LEARNING GOALS Identify the major hardware components in networks. Identify and explain the various types of computer networks. Identify the various types of transmission media Describe the role of software used in networks.3Why Networking ? Resource sharing Sharing hardware (printers, processors, etc.) Sharing software (programs, data files) High reliability Could set automatic backup of programs and data at different locations Fault tolerance (if one server is down, another provides service. If a disk fails, a mirror disk may be available) Cost saving Communication tool Internal email service Remote Access service24Computer Network Two or more computers that are interconnected using network interface cards (NICs) and transmission media like coaxial cables, Ethernet cords, radio signals. (Textbook, p. 194). Its scope determines how big is a networkOnce connected to the network, the computer (or another device) becomes a network node5Network scope Local area network (LAN): computer network where the nodes are all in close proximity spanning a room, building Campus Area Network (CAN): a larger LAN that spans a college campus or corporate facitilty. Metropolitan area network (MAN): network that serves an area of 3 to 30 miles - approximately the area of a typical city. Wide area network (WAN): a large network that encompasses parts of states, multiple states, countries, and the world6Transmission Media Physical media Transmission media used to physically connect nodes to the network Transmits electrical or optical signals Could be cooper wire or fiber optic cablePhysicalWireless37Transmission Media (Continued) Twisted PairCategory Use Signal Data rate Distance ProblemCategory 1 Telephone Analog/Digital <100Kbps 3-4 miles Security, noiseCategory 2 T1, ISDN Digital <2 Mbps 3-4 miles Security, noiseCategory 3 LANs Digital 10 Mbps 100 m Security, noiseCategory 4 LANs Digital 20 Mbps 100 m Security, noiseCategory 5 LANs Digital 100 Mhz 100 m Security, noiseCategory 6 LANs Digital 250 Mhz 100 m Security, noiseCategory 7 LANs Digital 600 Mhz 100 m Security, noise Fiber optic Thin glass fibers surrounded by coating Uses laser or light for data transmission Very fast (10+ Gbps, 100 miles without any repeater) Very secureSourcePhoto diode(LED or LD)DestinationPhoto receptor(LED or LD)Fiber optic cable8Wireless Media Uses electromagnetic waves or electromagnetic radiation for data transmission Propagation through space, and indirectly, through solid objects Two kinds of wireless media used Radio waves (radio Frequency) Affected by Multipath interference Highly vulnerable to snooping Limited distance Blocked by thick objects Infrared light Close proximity and “line of sight” location requiredLaptopComm. Tower9Computing Equipment Network interface card (NIC): Device that provides a computer with unique address Converts data into signal for transmission Hub / Switch: Central collection point for transmission media that interconnect computers Modem Converts digital data into analog signal and back again Router  special hardware that determines optimal routing path for data packets  Usually used to connect a LAN to a WAN Bridge Forwards messages between LANs410Small Network illustratedHub or SwitchMediaWide Area Network11Network Software Network operating system Used on servers Used for managing network resources Examples: Novell NetWare, Windows Server 2003 Workstation operating system Used on client PCs Used to manage local resources & access network resources Network monitoring software Packet sniffers – allow seeing data as it moves over network Keystroke monitors – allow seeing what users are typing12Network Topologies The configurations of network components How physically the network looks like How logically data is transferred on the network Types of network topologies: Bus Star Ring513Bus Network Topology Most simple network topology All devices connected to a common central cable called a “bus” Inexpensive If cable fails, the entire network will shut down14Star Network Topology Centered around central device called a hub or a switch All network nodes connect to the hub/switch Easy to install and update If hub fails, network fails15Ring Topology Node connected to a logical ring in a central device called MAU More reliable than bus or star Only one node sends at a time (no collisions) Expensive and limited speed616Network Architectures/Models Defines how the processing takes place on the network Two primary models Client-server Peer-to-peer (P2P)17Client-server model Nodes are either clients or servers Clients use services Servers provide services File service E-mail service Printing service Database service Client software on client node cooperates with server software on server node The WWW is the largest client server application18Client-server model Collaboration between Client and Server program719Client-server model Division of Labor Client program handles lighter work, such as user interface chores and light processing chores Server program handles heavy work, such as database retrievalClient Machine ServerClient ProgramServerProgram20Peer-to-Peer model All nodes on the network are equal. Any node can be both a client and a server.21Summary QuestionsBook Notes1) Name categories of computer networks based on their scope; i.e. their range of operation52) Name one example of: (a) WAN, (b) LAN3) Name physical and wireless media used in networking6-84) What is the role of (a) a modem, (b) a router, (c) a bridge?95) What is the difference between a Network operating system and a workstation operating system?116) What is a network topology?127) Distinguish between network topologies13-168) Distinguish between Client-server and P2P networks18-21822Problem Four students share a dorm. They would like to set up a network in order to share programs and data files. Three of the students own PCs and the fourth student has a laptop computer.Question: What computing equipments they need to buy in order to set up the network with a star