11NETWORKINGTECHNOLOGIESBUS3500 - Abdou Illia, Spring 2007(Week 8, Thursday 3/1/2007)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 High reliability Cost saving Communication tool24Computer Network An interconnection of computers and computing equipment using either wires or radio waves over small or large geographic distances“Connect to GHI”ABCDEFGHIJKLMNOOnce 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, or campus 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 in to the network Transmits electrical or optical signals Could be cooper wire or fiber optic cablePhysicalWireless37Transmission Media (Continued) Twisted PairSecurity, noise100 m600 MhzDigitalLANsCategory 7Security, noise100 m250 MhzDigitalLANsCategory 6Security, noise100 m100 MhzDigitalLANsCategory 5Security, noise100 m20 MbpsDigitalLANsCategory 4Security, noise100 m10 MbpsDigitalLANsCategory 3Security, noise3-4 miles<2 MbpsDigitalT1, ISDNCategory 2Security, noise3-4 miles<100KbpsAnalog/DigitalTelephoneCategory 1ProblemDistanceData rateSignalUseCategory Fiber optic Thin glass fibers surrounded by coating Uses lasers for light source 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 Widely used network topologies: Bus Star Ring Mesh513Bus 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 speed616Mesh Network Topology Every node connected to every other node Reliable If one device goes down, it is the only node affected Expensive Every node must be wired to every other node Difficult to add nodes If 32 nodes in a mesh network and wish to add a new node, how many new cables?17Network Architecture Defines how the processing takes place on the network Two primary types Client-server Peer-to-peer (P2P)18Client-server Network Architecture 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 application719Client-server Network Architecture Collaboration between Client and Server program20Client-server Network Architecture 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 ProgramServerProgram21Peer-to-Peer Network Architecture All nodes on the network are equal. Any node can be both a client and a server.822Summary Questions126) What is a network topology?13-167) Distinguish between network topologies18-218) Distinguish between Client-server and P2P networks115) What is the difference between a Network operating system and a workstation operating system?6-83) Name physical and wireless media used in networking2) Name one example of: (a) WAN, (b) LAN94) What is the role of (a) a modem, (b) a router, (c) a bridge?51) Name categories of computer networks based on their scope; i.e. their range of operationNotesMalaga23Problem 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.a) What computing equipments they need to buy in order to set up the network with a star topology?b) Suppose that they decided to set up a P2P wired network. They have purchased a 4-port 10/100BASE-TX Ethernet hub at www.cdw.com. What kind of physical media they need to