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Learn how to connect a PC to a local area network (LAN) and segment a network into segments. Understand network architecture, physical components, network technologies, and protocols needed for reliable communication. Explore different physical network architectures such as Ethernet, token ring, FDDI, and wireless LAN. Discover network architecture terminology, including network adapter, network port, and network protocols. Learn about Ethernet variations, cable types used with Ethernet, and Ethernet topologies like bus and star. Understand how Ethernet controls data traffic and explore token ring, FDDI, and wireless LANs. Finally, learn how to connect a PC to a network using network interface cards (NICs), bridges, and switches, and how to install NICs and network protocols in Windows.
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Chapter 11 PCs on a Network
You Will Learn… • How local networks are structured • How to connect a PC to a LAN and divide a network into segments • How to connect networks to each other
Network Architecture • Describes overall design of the network • Physical components • Network technologies • Interfacing software • Protocols needed to establish reliable communication among nodes
Physical Network Architectures • Ethernet (most popular) • Token ring • FDDI (Fiber Distributed Data Interface) • Wireless LAN technology
Network Architecture Terminology • Network adapter • Most often an expansion card called a network interface card (NIC) • Must match type and speed of physical network in use • Network port must match type of connectors used on the network • Network protocols • Hardware protocols (eg, Ethernet, Token Ring) • OS protocols (eg, NetBEUI, TCP/IP) continued…
Network Architecture Terminology • Packets, datagrams, or frames • Packets have maximum size depending on type of network • CRC (cyclical redundancy check) • Technique of calculating and comparing values
Ethernet Variations, Distinguished by Speed • 10-Mbps Ethernet • Uses either shielded twisted-pair (STP) cable, unshielded twisted-pair (UTP) cable, or coaxial cable • 100-Mbps Ethernet or Fast Ethernet • Uses UTP or STP cable • 100BaseFX uses fiber-optic cable (single-mode, multi-mode, and plastic) • 1000-Mbps Ethernet of Gigabit Ethernet • Uses twisted-pair and fiber-optic cable
Cable Types Used with Ethernet continued…
Ethernet Topology • Bus topology • Connects each node in a line • Does not have a centralized point of connection • Star topology • Connects all nodes to a centralized hub • More popular
Ethernet Network • A passive network • Contention-based system • Each computer contends for an opportunity to transmit on the network • Requires collision control
How Ethernet ControlsData Traffic • CSMA/CD (Carrier Sense Multiple Access with Collision Detection) • CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) • Token method
Token Ring • Physical star; logical ring • Data packet is preceded by a token • Transmits data at 4 Mbps or 16 Mbps • Uses a centralized device called a MAU (Multistation Access Unit)
FDDI • Use a token that travels in a ring • Data frames travel on the ring without the token • Multiple nodes can have data on the ring at the same time • Provides data transfer at 100 Mbps
Wireless LANs (WLANs) • Make connections using wireless NICs • Include antennas or infrared transmission to send and receive signals in places where networking cables are difficult to install • Can be used in combination with a wired LAN • Standards • 1999 IEEE 802.11b (Wi-Fi, AirPort) • Bluetooth • Slower than wired networks • Security is an issue
Connecting a PC to a Network • Requirements • NIC • Network cable (patch cable) • Device for PC to connect to (eg, hub) • How NICs work and how to install them • How to set up a network protocol • Using bridges and switches to divide a network into segments for improved performance
How NICs Work • Plug into motherboard expansion slot • Provide port(s) on back of card for connection to network • Manage communication and hardware network protocol for the PC
How NICs Work • Network in use is transparent to applications software using it • Network card • Sends and receives data to and from system bus in parallel • Sends and receives data to and from network in series • Uses a transceiver for signal conversion • Network nodes are identified by a MAC (Media Access Control) address
Network Cards • Requirements • IRQ • I/O address • Upper memory addresses (for DOS and Windows 9x real mode) • May be PnP or can use jumpers or DIP switches to determine resources to request
Considerations When Selecting a Network Card • Speed and type of network (except for wireless connections) • Type of cable (shielded twisted-pair, coaxial, or fiber-optic) • Type of slot (PCI or ISA)
Installing a Network Card and Protocol under Windows 9x • Windows 95 supports Ethernet, token ring, and ARCnet networking cards • Windows 98 supports ATM, Ethernet, token ring, FDDI, IrDA, and ARCnet networking cards
Installing a NIC UsingWindows 9x • Set DIP switches or jumpers and physically install the card • Turn on PC; Windows detects and configures new device • Select Device Manager to verify installation • View Properties window to confirm resources • IRQ and I/O address of the card can be found on Resources tab
Assigning NetBIOS Names • Only configuration required by NetBEUI • Limited to 15 characters • Windows 9x assumes that a computer name is a NetBIOS name • Access Control Panel; double-click Network icon; click Identification tab
Installing a NIC UnderWindows 2000/XP • Windows 2000 automatically detects an installed card and guides installation of drivers • Options for verifying error-free installation • Device Manager • Network and Dial-Up Connections applet in Control Panel • Installing NetBEUI Protocol will automatically bind itself to the NIC providing the connection • Give a host name to the computer
Installing a Wireless NIC • Use NIC’s configuration software to specify wireless network parameters • State • Current Channel • Current Tx Rate • Throughput, Link Quality, and Signal Strength • Computer must be within acceptable range of an access point or another wireless device that it will communicate with directly • Distance determined by type of technology used
Changing NIC Functions • Mode • SSID (service set identifier) • Tx Rate • PS Mode
Symptoms of NIC Problems • Cannot make connection to network • Network Neighborhood or My Network Places does not show any other computers on the network • Error message during installation • Device Manager shows yellow exclamation point or red X beside name of NIC • No lights on NIC
Troubleshooting a Network Connection • Check connections in rest of network • Reboot PC and reset network connections • Make sure NIC and its drivers are installed • For TCP/IP network, use ping 127.0.0.1 command to determine whether NIC and IP protocol are working • Check for an IRQ conflict • Check cabling and ports • Confirm most current version of motherboard BIOS
Segmenting a Network • Decreases amount of traffic on overall network • Done through use of bridges and switches • More intelligent than hubs • Make decisions about whether or not to allow traffic to pass, or where to forward that traffic • Use MAC addresses, which they store in routing tables, to determine where to send packets