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1 Chapter 3 NETWORK CONNECTION HARDWARE Chapter 3: NETWORK CONNECTION HARDWARE NETWORK INTERFACE ADAPTER Provides the link between a computer and the network Requires a device driver to perform both data-link and physical layer functions Plugs into a bus slot or universal serial bus (USB) port on a computer Also referred to as a network interface card (NIC) 2 Chapter 3: NETWORK CONNECTION HARDWARE A NETWORK INTERFACE ADAPTER 3 Chapter 3: NETWORK CONNECTION HARDWARE TRANSMISSION FUNCTIONS Network interface adapters perform the following functions during data transmission: Data transfer, buffering, and encapsulation Media Access Control (MAC) Parallel/ serial conversion Signal encoding and amplification 4 Chapter 3: NETWORK CONNECTION HARDWARE NETWORK INTERFACE ADAPTER FEATURES Multiple duplex modes and autonegotiation of modes Processor offloading features Bus mastering Checksum processing Transmission Control Protocol (TCP) segmentation IP Security (IPSec) processing Network management Wake on LAN 5 Chapter 3: NETWORK CONNECTION HARDWARE HALF-DUPLEX AND FULL-DUPLEX MODES 6 Chapter 3: NETWORK CONNECTION HARDWARE 7 SELECTION CRITERIA When selecting network interface adapters, you must consider the following: The data-link layer protocol being implemented and the specific standard The transmission speed requirements for the local area network (LAN) The specific cabling and connector types that will be used Each computer’s bus architecture and resource availability Network interface driver availability The operating system type Chapter 3: NETWORK CONNECTION HARDWARE 8 INSTALLING A NETWORK INTERFACE ADAPTER IN A COMPUTER NIC Installation To install a network interface adapter: 1. Physically insert the network interface adapter card into the slot. 2. Configure the card to use the appropriate hardware resources. 3. Install the card’s device driver. Chapter 3: NETWORK CONNECTION HARDWARE A NETWORK INTERFACE ADAPTER IN A COMPUTER 9 Chapter 3: NETWORK CONNECTION HARDWARE 10 CONFIGURING A NETWORK INTERFACE ADAPTER Network interface adapters that do not support plug and play (PnP) must be manually configured for some or all of the following hardware resources: Interrupt request (IRQ) I/O Memory address Direct memory access (DMA) channel Chapter 3: NETWORK CONNECTION HARDWARE 11 NETWORK INTERFACE ADAPTER DEVICE DRIVERS Network interfaces require a device driver to provide the link between the computer and the interface. Operating systems ship with device drivers for common interfaces. Operating systems that support PnP detect and configure the interface automatically. You can get drivers from the manufacturer’s Web site. The driver configuration must match the interface’s resource settings. Chapter 3: NETWORK CONNECTION HARDWARE 15 TROUBLESHOOTING A NETWORK INTERFACE ADAPTER To troubleshoot the suspect network interface adapter, open the computer case and do the following: Verify that the interface is seated properly in the bus slot. Remove the card, clean the slot, and then reseat the card in the same slot or try another slot. Test a different interface (known to be functional) in the same slot and in a different slot Chapter 3: NETWORK CONNECTION HARDWARE PHYSICAL, DATA-LINK, AND NETWORK LAYER HARDWARE 16 Chapter 3: NETWORK CONNECTION HARDWARE 17 HUBS, REPEATERS, AND CONCENTRATORS Hubs, repeaters, and concentrators are all physical layer devices that Amplify and repeat signals Extend the distance of a network Chapter 3: NETWORK CONNECTION HARDWARE THICK ETHERNET REPEATERS Thick Ethernet repeaters extend the distance of a bus network. The maximum segment length is 500 meters. The maximum network distance is 2500 meters. You must observe the 5-4-3 rule. 18 Chapter 3: NETWORK CONNECTION HARDWARE 19 THIN ETHERNET REPEATERS Thin Ethernet repeaters extend the distance of a bus network. The maximum segment length is 185 meters. The maximum network distance is 925 meters. You must observe the 5-4-3 rule. Chapter 3: NETWORK CONNECTION HARDWARE AN ETHERNET REPEATER 20 Chapter 3: NETWORK CONNECTION HARDWARE 21 10BASE-T AND 100BASE-X HUBS 10Base-T and 100Base-TX/100Base-T4 standards define Ethernet networks that function at 10 Mbps and 100 Mbps, using baseband signaling over twisted-pair wire. 10Base-T Maximum distance limitation for each connection: 100 meters, including workstation-to-hub and hub-to-hub connections Can have up to four hubs connected to form a hierarchical star Includes an internal crossover circuit Uses an uplink port to form a hierarchical star Chapter 3: NETWORK CONNECTION HARDWARE 22 10BASE-T AND 100BASE-X HUBS (CONT.) 100Base-TX and 100Base-T4 There are two types of hubs: Class I and Class II. The maximum distance for each node connection is 100 meters. Class II hub-to-hub connections can be no more than 5 meters long. Chapter 3: NETWORK CONNECTION HARDWARE HUB CONNECTIONS 23 Play Video Chapter 3: NETWORK CONNECTION HARDWARE 10BASE-T HUB 24 Chapter 3: NETWORK CONNECTION HARDWARE 25 BRIDGES AND SWITCHES Are data-link layer devices that use destination addresses to forward frames Are protocol independent Do not filter broadcast packets Do not define separate networks Two forwarding modes in switches: cut-through and store-and-forward One forwarding mode in bridges: store-and-forward Chapter 3: NETWORK CONNECTION HARDWARE CUT-THROUGH SWITCHING 26 Hubs & Switches The cut-through method is the fastest way to forward frames. Looks at only the first 6 bytes (destination MAC address) before forwarding Does not perform cyclical redundancy check (CRC) on the frame contents Does not define separate collision domains Chapter 3: NETWORK CONNECTION HARDWARE 27 STORE-AND-FORWARD SWITCHING Store-and-forward switching is slower but more reliable than the cut-through method of forwarding frames. Store-and-forward switching pulls in the entire frame and performs a CRC check on the frame contents. Each port defines a separate collision domain. Chapter 3: NETWORK CONNECTION HARDWARE 28 TRANSPARENT BRIDGING AND SWITCHING Perform three basic functions: Flood Frames with unidentified destination addresses are transmitted out all ports except the one they were received through. Learn Switches use the source addresses within frames to learn which devices use specific ports, and then they use this information to build their internal address tables. Forward Frames are selectively forwarded to a port using known destination addresses stored in the MAC address table. Chapter 3: NETWORK CONNECTION HARDWARE FLOODING AND LEARNING 29 Chapter 3: NETWORK CONNECTION HARDWARE FORWARDING 30 Chapter 3: NETWORK CONNECTION HARDWARE 31 OTHER BRIDGING TECHNOLOGIES Source route bridging Source route bridging is used in Token Ring networks. The source host determines the path through the network, not the bridge. Bridges add path information when frames are forwarded and use this information to continue to forward frames between source and destination hosts. Translation bridging Translation bridging is used to connect dissimilar data-link architectures. Remote bridge A remote bridge connects two segments across a wide area network (WAN) link. Chapter 3: NETWORK CONNECTION HARDWARE 32 OTHER DATA-LINK LAYER TECHNOLOGIES Spanning tree protocol Used to avoid bridging loops Ensures a single active path to all segments within a LAN Virtual LANs (VLANs) Are logical LANs defined on switches Layer 3 switches Have built-in routing capabilities Chapter 3: NETWORK CONNECTION HARDWARE SPANNING TREE 33 Chapter 3: NETWORK CONNECTION HARDWARE VLANS 34 Chapter 3: NETWORK CONNECTION HARDWARE ROUTERS 35 Bridges & Routers Routers are network layer devices that connect LANs. Connect similar or different data-link layer LANs Must understand and support the network layer protocol and addressing Perform fragmentation Strip the data-link header and footer off received frames Add a new data-link header and footer before transmitting frames Use routing protocols to build routing tables and forward frames Define separate broadcast domains Chapter 3: NETWORK CONNECTION HARDWARE A SIMPLE ROUTED NETWORK 36 Chapter 3: NETWORK CONNECTION HARDWARE A ROUTED INTERNETWORK 37 Chapter 3: NETWORK CONNECTION HARDWARE GATEWAYS Can include the functions of all seven layers of the OSI model Connect dissimilar systems and protocols Perform translation and conversion services 38 Chapter 3: NETWORK CONNECTION HARDWARE 39 SUMMARY Network interface adapters provide the physical link between computers and the network. Hubs are physical layer devices that amplify and repeat signals out all ports except the one they were received through. Bridges and switches are data-link layer devices that use destination addresses to forward frames. Spanning tree is used by bridges and switches to avoid loops. VLANs are logical LANs used to group computers within a switched network. Routers are network layer devices that forward datagrams between LANs. Gateways translate and convert protocols between dissimilar systems.