Chapter 2 Chapter 2: Basic Network Design and Protocols

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

Chapter 2 Learning Objectives n Describe Microsoft networking services and protocols n Determine how to select the topology and communications cable for a given installation n Determine how to select the right protocol for a given installation

Chapter 2 An Overview of Networks n Local area networks (LANs) n Metropolitan area networks (MANs) n Enterprise networks n Wide area networks (WANs)

Chapter 2 An Overview of Networks n Local area networks (LANs) u A series of interconnected computers, printers, and other equipment that share hardware and software resources u Usually limited to a given floor, office area, or building

Chapter 2 A Sample LAN Statistics lab Business lab Server

Chapter 2 An Overview of Networks n Metropolitan area networks (MANs) u A network that links multiple LANs within a large city or metropolitan region F ex. Intel Oregon (Washington County) Jones Farm (Hillsboro)Jones Farm (Hillsboro) Hawthorne Farm (Hillsboro)Hawthorne Farm (Hillsboro) Cornell Oaks (Beaverton)Cornell Oaks (Beaverton) Ronler Acres (Hillsboro)Ronler Acres (Hillsboro) Aloha (Aloha)Aloha (Aloha)

Chapter 2 An Overview of Networks n Enterprise networks F A network that reaches throughout a large area (e.g., cities, states) connecting many kinds of LANs and network resources F Generally, privately-owned/leased wires n Wide area networks (WANs) F A far-reaching system of networks that can extend across state lines and across continents F Slower links between sites (LANs)

Chapter 2 Enterprise Networks Connected into a WAN Toronto Chicago Detroit Windows NT server IBM AS/400 Workstation Printer Windows NT server Plotter NetWare server Workstation Mainframe Production color laser printer Telecommunications line Network Remote network connection Supercomupter

Chapter 2 Planning a Network n Size and purpose of organization n Potential growth of the organization in terms of people and services n Number of mission-critical applications on the network n Important cycles for the business continued

Chapter 2 Planning a Network n Relationship of network resources to the mission of the business n Security needs n Amount budgeted for network and computer resources

Chapter 2 Developing a Plan n Number and kinds of workstations and their operating systems n Number and kinds of server and host computers and their operating systems n All software applications that will be networked continued

Chapter 2 Developing a Plan n Characteristics of offices and the building layout n Network management needs n Cabling types and topologies

Chapter 2 Network Topologies n Topology: the physical layout of a network combined with its logical characteristics n Types of network topologies u Bus u Ring u Star u Bus networks in a physical star layout

Chapter 2 Bus Topology n Nodes are connected to a segment of cable in the logical shape of a line, with a terminator at each end F node = network entity (computer, printer, etc.) n Network segment must adhere to IEEE length specifications F IEEE = Institute of Electrical and Electronics Engineers

Chapter 2 Bus Topology Laptop computer Terminator Laser printer File server Pen computer Terminator Workstation

Chapter 2 Bus Topology Advantages and Disadvantages n Advantages u Works well for small networks u Relatively inexpensive to implement u Easy to add another workstation n Disadvantages u Potentially high management costs u Can become congested with network traffic

Chapter 2 Ring Topology n A network in the form of a continuous ring, or circle, with nodes connected around the ring n A continuous path for data with no logical beginning or ending point, thus no terminators

Chapter 2 Ring Topology Workstation File server Ring

Chapter 2 Ring Topology Advantages and Disadvantages n Advantages u Easier to maintain than the bus u Enables more reliable communications than the bus (distance and volume) n Disadvantages u More expensive to implement than the bus u Not used as widely as the bus; fewer options for equipment and expansion

Chapter 2 Star Topology n Configured with a central hub and individual cable segments connected to the hub in the shape of a star n Oldest communications design method

Chapter 2 Star Topology Workstation Hub File server

Chapter 2 Star Topology Advantages and Disadvantages n Advantages u Low startup costs (ex. share w/phone wire) u Easier to manage than the bus u Easy to expand u Widely used; variety of equipment available n Disadvantages u Hub is a single point of failure u Requires more cable than bus designs

Chapter 2 Bus Networks in a Physical Star Layout n Combine logical communications of a bus with physical layout of a star n Advantages u No exposed terminators u Multiple hubs can be connected for expansion u Popular alternative; wide range of equipment available u Compatible with bus protocols (Ethernet)

Chapter 2 Expanding a Bus-star Network Workstation Hub File server

Chapter 2 Network Communications Media n Coaxial cable u Thick coaxial cable u Thin coaxial cable n Twisted-pair cable u Shielded twisted-pair cable (STP) u Unshielded twisted-pair cable (UTP) n Fiber-optic cable

Chapter 2 Characteristics of Network Communications Media n Data transfer speed n Use in specific network topologies n Distance requirements n Cable and cable component costs n Additional network equipment required n Ease of installation n Immunity to interference from outside sources n Upgrade options

Chapter 2 Thick Coaxial Cable n Used on early networks, particularly as a backbone to join different networks n Advantages u Durable and reliable u Great resistance to signal interference n Disadvantages u Difficult to manipulate and terminate u Expensive to purchase and install

Chapter 2 Thick Coaxial Cable Copper center conductor Conductor insulation Aluminum sleeve PVC or Teflon jacket

Chapter 2 Thin Coaxial Cable n Used in networks to connect desktops/workstations, and servers n Easy and cheap to install A T-connector with a terminator at one end BNC T-connector BNC connector Terminator

Chapter 2 Twisted-pair Cable n Most popular communications medium n More flexible than coax for running through walls and around corners n Can be adapted for high speed communications n Connectors are less expensive, less susceptible to damage, and easy to connect

Chapter 2 Shielded Twisted-Pair Cable n Shielding reduces interruptions of the communication signal caused by electrical interference Plastic encasement Shielding Color-coded insulation Copper wire conductor

Chapter 2 Unshielded Twisted-pair Cable n Most frequently used because of low cost, relatively easy installation, and high reliability Plastic encasement Color-coded insulation Copper wire conductor

Chapter 2 Fiber-optic Cable n Advantages u Able to carry large amounts of data over long distances u No problem with electrical interference u Difficult for unauthorized taps to be placed n Disadvantages u Very fragile and relatively expensive u Requires specialized training to install

Chapter 2 Fiber-optic Cable n Single-mode transmission u just one wavelength (color) of light u simpler (therefore cheaper) hardware n Multi-mode transmission u several wavelengths (colors) at a time u carries much more information u more complex hardware (therefore more expensive) u frequently used for “backbone” connections

Chapter 2 Fiber-optic Cable Optical fiber (core) Glass claddingProtective outer sheath (jacket)

Chapter 2 Network Interface Card (NIC) n Connects a workstation, file server, or other network equipment to communications cable n Contains a transceiver for sending and receiving data signals n Software drivers encode and decode data n Built-in memory chips provide temporary storage n Designed for coaxial, twisted-pair, or fiber- optic cable

Chapter 2 Connecting Cable to a NIC Connector just like telephone connector (RJ-11, four wire; RJ-45, eight wire).

Chapter 2 Transporting Data on the Communications Cable n Ethernet u Used more often than token ring u Offers more network design options u Offers more high-speed networking options u More widely supported by network devices n Token ring u Highly reliable network communications, particularly on busy networks

Chapter 2 Ethernet n Typically implemented in bus or star (or combined) topology n Uses the CSMA/CD (Carrier Sense Multiple Access with Collision Detection) access method for data transmission on a network n Originally, 10Mbps (megabits/sec); now 100Mbps and up to Gbps speeds available

Chapter 2 Protocols n NetBIOS (Network Basic Input/Output System) n NetBEUI (NetBIOS Extended User Interface) n NDIS (Network Driver Interface Specification) n NWLink (NetWare Link) n ODI (Open Datalink Interface) n TCP/IP (Transmission Control Protocol/Internet Protocol) n DLC (Data Link Control Protocol) n AppleTalk

Chapter 2 Microsoft Tools for Ethernet and Token Ring Communications continued

Chapter 2 Microsoft Tools for Ethernet and Token Ring Communications

Chapter 2 Protocol Stack continued n Driver is lowest-level u runs in kernel u we’ll cover this more later n Protocol(s) next u TCP/IP, SPX/IPX, NetBEUI, etc. n “Client”(s) next u Client for Microsoft Networks (uses NetBEUI) u Novell NetWare or MS Client for NetWare u Applications (SMTP, HTTP, FTP, telenet…) n Akin to “7-layer model” but not exactly

Chapter 2 NetBIOS n A combination software interface and network naming convention n Available in Microsoft operation systems through the file NETBIOS.DLL

Chapter 2 NetBIOS/NetBEUI Communications Sent onto the network (Transport driver) Started NetBIOS-compatible application NetBIOS software interface NetBEUI protocol

Chapter 2 NetBEUI n Well-suited for small LANs using Microsoft or IBM operating systems u Simple to install u Compatible with Microsoft workstation and server operating systems u Nearly limitless communication sessions on one network u Low memory requirements; can be quickly transported over small networks

Chapter 2 NDIS n A set of standards developed by Microsoft for network drivers n Enables communication between a NIC and a protocol n Enables use of multiple protocols on same network

Chapter 2 Binding a Protocol to a NIC Network protocol (such as NetBEUI) NDIS driver Network interface card (NIC)

Chapter 2 ODI n Open data-link interface n A driver that is used by Novell NetWare networks to transport multiple protocols on the same network

Chapter 2 NWLink n A network protocol that simulates the IPX/SPX protocol for Microsoft Windows 95 and NT communications with Novell NetWare file servers and compatible devices

Chapter 2 NWLink Advantages and Disadvantages n Advantages u Has routing capabilities over enterprise networks u Easy to install u More effective communications with NetWare file servers than the ODI driver n Disadvantages u Not transported as fast as NetBEUI u A “chatty” protocol - each packet transmitted must be acknowledged by the receiving node

Chapter 2 TCP/IP n TCP portion performs extensive error checking to ensure that data are delivered successfully F TCP == “transmission control protocol” n IP portion consists of rules for packaging data and ensuring that is reaches the correct destination address F IP == “Internet protocol”

Chapter 2 TCP/IP Advantages n Well-suited for medium and large networks n Designed for routing; has high degree of reliability n Used worldwide for directly connecting to the Internet and by Web servers n Compatible with standard tools for analyzing network performance n Includes ability to use DHCP and WINS through a Microsoft NT server

Chapter 2 TCP/IP Disadvantages n More difficult to set up and maintain than NetBEUI or IPX/SPX F but frequently worth the pain n Can be slower than IPX/SPX and NetBEUI on networks with light to medium traffic

Chapter 2 Protocols Associated with TCP/IP n Telnet u Provides terminal emulation services n File Transfer Protocol (FTP) u Enables files to be transferred across a network or the Internet n Simple Mail Transfer Protocol (SMTP) u An protocol n Domain Name Service (DNS) u Resolves domain computer names to IP addresses or vice versa

Chapter 2 Connecting to IBM Mainframes with DLC n Enables communications with an IBM mainframe or minicomputer n Advantage u An alternative to TCP/IP n Disadvantages u Not routable u Not truly designed for peer-to-peer communications between workstations

Chapter 2 Connecting to Macintosh Computers with AppleTalk n A peer-to-peer protocol used on networks for communications between Macintosh computers n Supported in very limited ways on non- Macintosh networks

Chapter 2 Selecting the Right Topology and Communications Cable n Network topology selection depends on the size and needs of your network n Cable selection depends on the physical topology

Chapter 2 Selecting the Right Protocol n Do frames need to be routed? n Is the network small, medium, or large? n Are there Microsoft NT servers? n Are there mainframe host computers? n Are there NetWare servers? n Is there direct access to the Internet or to Web-based intranet applications? n Are there mission-critical applications?

Chapter 2 Chapter Summary n A Windows NT server operates in the context of a network. u LAN, enterprise, WAN u Factors in preparing a network F Needs of organization F Software that will be used F Existing computer equipment F Security requirements continued

Chapter 2 Chapter Summary n Network design employs the bus, ring, and star topologies. n Communications cable includes coax, twisted-pair, and fiber-optic cable. continued

Chapter 2 Chapter Summary n Network communications are enabled through network transport methods such as Ethernet and token ring. u Ethernet offers expansion and high-speed networking options u Token ring offers reliable communications and time-proven technology continued

Chapter 2 Chapter Summary n Protocols such as NetBEUI and TCP/IP establish a communications format that is understood by the computers on a network. n Microsoft networks support many different protocols for different network sizes and requirements.