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Chapter 2: Basic Network Design and Protocols

Chapter 2: Basic Network Design and Protocols

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Chapter 2: Basic Network Design and Protocols

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  1. Chapter 2: Basic Network Design and Protocols

  2. Learning Objectives • Plan a network • Explain network topologies • Describe network communications media • Explain how network cable connects to a computer • Describe the Ethernet and token ring transport methods continued

  3. Learning Objectives • Describe Microsoft networking services and protocols • Determine how to select the topology and communications cable for a given installation • Determine how to select the right protocol for a given installation

  4. An Overview of Networks • Local area networks (LANs) • Metropolitan area networks (MANs) • Enterprise networks • Wide area networks (WANs)

  5. An Overview of Networks • Local area networks (LANs) • A series of interconnected computers, printers, and other equipment that share hardware and software resources • Usually limited to a given floor, office area, or building

  6. A Sample LAN Statistics lab Server Business lab

  7. An Overview of Networks • Metropolitan area networks (MANs) • A network that links multiple LANs within a large city or metropolitan region • ex. Intel Oregon (Washington County) • Jones Farm (Hillsboro) • Hawthorne Farm (Hillsboro) • Cornell Oaks (Beaverton) • Ronler Acres (Hillsboro) • Aloha (Aloha)

  8. An Overview of Networks • Enterprise networks • A network that reaches throughout a large area (e.g., cities, states) connecting many kinds of LANs and network resources • Generally, privately-owned/leased wires • Wide area networks (WANs) • A far-reaching system of networks that can extend across state lines and across continents • Slower links between sites (LANs)

  9. Enterprise Networks Connected into a WAN Workstation Workstation Windows NT server Plotter Network NetWare server Mainframe Network Supercomupter Toronto Production color laser printer Remote network connection Chicago Telecommunications line Windows NT server IBM AS/400 Network Detroit Workstation Printer

  10. Planning a Network • Size and purpose of organization • Potential growth of the organization in terms of people and services • Number of mission-critical applications on the network • Important cycles for the business continued

  11. Planning a Network • Relationship of network resources to the mission of the business • Security needs • Amount budgeted for network and computer resources

  12. Developing a Plan • Number and kinds of workstations and their operating systems • Number and kinds of server and host computers and their operating systems • All software applications that will be networked continued

  13. Developing a Plan • Characteristics of offices and the building layout • Network management needs • Cabling types and topologies

  14. Network Topologies • Topology: the physical layout of a network combined with its logical characteristics • Types of network topologies • Bus • Ring • Star • Bus networks in a physical star layout

  15. Bus Topology • Nodes are connected to a segment of cable in the logical shape of a line, with a terminator at each end • node = network entity (computer, printer, etc.) • Network segment must adhere to IEEE length specifications • IEEE = Institute of Electrical and Electronics Engineers

  16. Bus Topology Terminator Laser printer Workstation File server Laptop computer File server Pen computer Workstation Terminator

  17. Bus TopologyAdvantages and Disadvantages • Advantages • Works well for small networks • Relatively inexpensive to implement • Easy to add another workstation • Disadvantages • Potentially high management costs • Can become congested with network traffic

  18. Ring Topology • A network in the form of a continuous ring, or circle, with nodes connected around the ring • A continuous path for data with no logical beginning or ending point, thus no terminators

  19. Ring Topology Workstation File server Ring Workstation Workstation

  20. Ring TopologyAdvantages and Disadvantages • Advantages • Easier to maintain than the bus • Enables more reliable communications than the bus (distance and volume) • Disadvantages • More expensive to implement than the bus • Not used as widely as the bus; fewer options for equipment and expansion

  21. Star Topology • Configured with a central hub and individual cable segments connected to the hub in the shape of a star • Oldest communications design method

  22. Star Topology File server Workstation Hub Workstation Workstation Workstation Workstation

  23. Star TopologyAdvantages and Disadvantages • Advantages • Low startup costs (ex. share w/phone wire) • Easier to manage than the bus • Easy to expand • Widely used; variety of equipment available • Disadvantages • Hub is a single point of failure • Requires more cable than bus designs

  24. Bus Networks in a Physical Star Layout • Combine logical communications of a bus with physical layout of a star • Advantages • No exposed terminators • Multiple hubs can be connected for expansion • Popular alternative; wide range of equipment available • Compatible with bus protocols (Ethernet)

  25. Expanding a Bus-star Network Workstation File server Hub Hub

  26. Network Communications Media • Coaxial cable • Thick coaxial cable • Thin coaxial cable • Twisted-pair cable • Shielded twisted-pair cable (STP) • Unshielded twisted-pair cable (UTP) • Fiber-optic cable

  27. Characteristics of Network Communications Media • Data transfer speed • Use in specific network topologies • Distance requirements • Cable and cable component costs • Additional network equipment required • Ease of installation • Immunity to interference from outside sources • Upgrade options

  28. Thick Coaxial Cable • Used on early networks, particularly as a backbone to join different networks • Advantages • Durable and reliable • Great resistance to signal interference • Disadvantages • Difficult to manipulate and terminate • Expensive to purchase and install

  29. Thick Coaxial Cable Copper center conductor Conductor insulation Aluminum sleeve PVC or Teflon jacket

  30. Thin Coaxial Cable • Used in networks to connect desktops/workstations, and servers • Easy and cheap to install Terminator BNC connector BNC T-connector • A T-connector with a terminator at one end

  31. Twisted-pair Cable • Most popular communications medium • More flexible than coax for running through walls and around corners • Can be adapted for high speed communications • Connectors are less expensive, less susceptible to damage, and easy to connect

  32. Shielded Twisted-Pair Cable • Shielding reduces interruptions of the communication signal caused by electrical interference Color-coded insulation Copper wire conductor Plastic encasement Shielding

  33. Unshielded Twisted-pair Cable • Most frequently used because of low cost, relatively easy installation, and high reliability Copper wire conductor Plastic encasement Color-coded insulation

  34. Fiber-optic Cable • Advantages • Able to carry large amounts of data over long distances • No problem with electrical interference • Difficult for unauthorized taps to be placed • Disadvantages • Very fragile and relatively expensive • Requires specialized training to install

  35. Fiber-optic Cable • Single-mode transmission • just one wavelength (color) of light • simpler (therefore cheaper) hardware • Multi-mode transmission • several wavelengths (colors) at a time • carries much more information • more complex hardware (therefore more expensive) • frequently used for “backbone” connections

  36. Fiber-optic Cable Optical fiber (core) Protective outer sheath (jacket) Glass cladding

  37. Network Interface Card (NIC) • Connects a workstation, file server, or other network equipment to communications cable • Contains a transceiverfor sending and receiving data signals • Software drivers encode and decode data • Built-in memory chips provide temporary storage • Designed for coaxial, twisted-pair, or fiber-optic cable

  38. Connecting Cable to a NIC Connector just like telephone connector (RJ-11, four wire; RJ-45, eight wire).

  39. Transporting Data on the Communications Cable • Ethernet • Used more often than token ring • Offers more network design options • Offers more high-speed networking options • More widely supported by network devices • Token ring • Highly reliable network communications, particularly on busy networks

  40. Ethernet • Typically implemented in bus or star (or combined) topology • Uses the CSMA/CD (Carrier Sense Multiple Access with Collision Detection) access method for data transmission on a network • Originally, 10Mbps (megabits/sec); now 100Mbps and up to Gbps speeds available

  41. Protocols • NetBIOS (Network Basic Input/Output System) • NetBEUI (NetBIOS Extended User Interface) • NDIS (Network Driver Interface Specification) • NWLink (NetWare Link) • ODI (Open Datalink Interface) • TCP/IP (Transmission Control Protocol/Internet Protocol) • DLC (Data Link Control Protocol) • AppleTalk

  42. Microsoft Tools for Ethernet and Token Ring Communications continued

  43. Microsoft Tools for Ethernet and Token Ring Communications

  44. Protocol Stack • Driver is lowest-level • runs in kernel • we’ll cover this more later • Protocol(s) next • TCP/IP, SPX/IPX, NetBEUI, etc. • “Client”(s) next • Client for Microsoft Networks (uses NetBEUI) • Novell NetWare or MS Client for NetWare • Applications (SMTP, HTTP, FTP, telenet…) • Akin to “7-layer model” but not exactly continued

  45. NetBIOS • A combination software interface and network naming convention • Available in Microsoft operation systems through the file NETBIOS.DLL

  46. NetBIOS/NetBEUI Communications Started NetBIOS-compatible application NetBIOS software interface (Transport driver) NetBEUI protocol Sent onto the network

  47. NetBEUI • Well-suited for small LANs using Microsoft or IBM operating systems • Simple to install • Compatible with Microsoft workstation and server operating systems • Nearly limitless communication sessions on one network • Low memory requirements; can be quickly transported over small networks

  48. NDIS • A set of standards developed by Microsoft for network drivers • Enables communication between a NIC and a protocol • Enables use of multiple protocols on same network

  49. Binding a Protocol to a NIC Network protocol (such as NetBEUI) NDIS driver Network interface card (NIC)

  50. ODI • Open data-link interface • A driver that is used by Novell NetWare networks to transport multiple protocols on the same network