Bài giảng Network - Chapter 02

Chapter Overview Network CablesNetwork Interface AdaptersNetwork Hubs 1Cable Topologies BusStarRingHierarchical starMesh Wireless 2Bus Topology3Star Topology 4Ring Topology 5Ring Network Types Physical ring Logical ringDouble ring 6Hierarchical Star Topology7Mesh LAN Topology 8Mesh Internetwork 9Wireless Topologies Ad hoc topology: Connects two or more wireless computers communicating with each other onlyInfrastructure network: Connects wireless computers communicating with a network access point that provides access to a standard cabled network 10Coaxial Cable 11Coaxial Cable Types  RG-8RG-58ApplicationThick EthernetThin EthernetThickness0.405 inch0.195 inchConnector TypeNBNC with a T-fitting12Twisted-Pair Cable 13UTP Cable Grades EIA/TIA GradeApplicationsCategory 3Voice-grade telephone networks, 10-Mbps Ethernet, 4-Mbps Token Ring, 100Base-T4 Fast Ethernet, and 100Base-VG-AnyLAN Category 416-Mbps Token Ring Category 5100Base-TX Fast Ethernet, Synchronous Optical Network (SONET), and Optical Carrier (OC3) Asynchronous Transfer Mode (ATM) Category 5e or higher1000Base-T (Gigabit Ethernet) 14Fiber Optic Cable15Fiber Optic Connectors16Fiber Optic Cable TypesSinglemode: Used for wide area networks (WANs) and other long cable runsMultimode: Used for local area networks (LANs) and short cable runs 17Network Interface Adapters Called network interface cards (NICs) when installed in expansion slotsProvide the computer with an interface to the networkUsually take the form of an expansion cardCan be integrated into the motherboard 18Network Interface Adapter Functions Data-link protocol implementationData encapsulationSignal encoding and decodingData transmission and receptionData bufferingSerial/parallel conversionMedia Access Control (MAC) 19NIC Purchasing Checklist Does the NIC use the correct data-link layer protocol?Does the NIC use the correct bus type?Does the NIC have the correct cable connector? 20Installing a NIC To install a NIC into a standard expansion slot on a desktop computer: 1. Power off the computer. 2. Open the computer case. 3. Locate a free slot. 4. Remove the slot cover. 5. Insert the card into the slot. 6. Secure the card in the slot. 7. Close the computer case.21Network Interface Adapter Requirements Network interface adapters use the following hardware resources: An interrupt request (IRQ)An input/output (I/O) port addressA memory addressA direct memory access (DMA) channel Most network interface adapters require only an IRQ and an I/0 port address.22Troubleshooting Network Interface Adapters Network interface adapters rarely malfunction.Test all other networking components first.Use the network interface adapter manufacturer’s diagnostics.Replace network interface adapters rather than trying to repair them. 23Understanding Ethernet Hubs A hub connects all of the computers on a star or ring network.Ethernet hubs are available in various sizes.A hub creates a shared network medium on a LAN. 24Connecting Ethernet Hubs Most hubs have an uplink port.Uplink ports provide a straight-through circuit.To connect two hubs, plug a cable into the uplink port on one hub and into a standard port on the other hub. 25Understanding MAUs26Chapter Summary The network topology is the pattern used to connect computers and other devices with the cable or other network medium.The three primary LAN topologies are bus, star, and ring.Unshielded twisted-pair (UTP) cable in the star topology is the most common network medium used today.A network interface adapter provides the interface that enables a computer to connect to a network.The network interface adapter and its driver implement the data-link layer protocol on the computer.Hubs are devices that connect computers on a star or ring network. 27