1. 15-1 Networking

2. 15-2 Section Objectives After completing this section you will be able to:  Differentiate between peer-to-peer and server-based networks  Identify commonly used network topologies  Compare and contrast types of network cabling  Explain the differences between various network access methods  Explain how Ethernet works  Identify OSI model layers and the network devices that work at each layer  Articulate commonly used network protocols  Define the purpose and identification of a MAC address and an IP address  Apply IP addressing concepts  Define the purpose of DHCP, WINS, and DNS  Configure an NIC for network connectivity

3. 15-3 Networking Overview  A network is two or more devices capable of communicating and sharing resources between them.  Types of networks: –PAN (Personal Area Network) – Personal devices such as PDAs can communicate in close proximity through a wired or wireless network. –LAN (Local Area Network) – A group of devices sharing resources in a single area such as a room or a building. –MAN (Metropolitan Area Network) – Connectivity of sites within a city. –WAN (Wide Area Network) – Two or more LANs communicating, often across large distances. The most famous WAN is the Internet.

4. 15-4 Types of Local Area Networks  Types of LANs: –Server-Based Network (client-server network)– A type of LAN wherein users login to a controlling computer, called a server and is more secure. These networks normally consist of 10 or more computers. –Peer-to-Peer Network – A type of LAN wherein each computer user acts as a server. Each computer stores password and sharing information for its own resources. Usually has fewer than 10 computers.  NOS (Network Operating System) – Special operating system on a server containing utilities for managing users, resources, and security.

5. 15-5 Types of Local Area Networks Server-Based network Network – Figure 15.1

6. 15-6 Types of Local Area Networks Network – Figure 15.2 Peer-to Peer network

7. 15-7 Network Topologies  Physical network topology – How the network is wired.  Ethernet – The most common type of network.  Hub – A device that allows multiple device connections. Hubs are not as intelligent as switches.  Switch – A switch looks at each data frame as it comes through each port.  Star Topology – Most common network topology. Each device connects to a central hub or switch.

8. 15-8 Network Topologies Network – Figure 15.4 Hub (switch)

9. 15-9 Network Topologies Network – Figure 15.5 Star topology

10. 15-10 Network Topologies Network – Table 15.2 Network topologies

11. 15-11 Network Media Overview  Cable or air are used as mediums for transporting network data.  The most common types are twisted-pair and fiber- optic, although coax is still used in some old networks.  Wireless networks use the air to transmit data over radio frequencies.

12. 15-12 Copper Media  Twisted-Pair Cable – Network cable of eight copper wires twisted into four pairs to prevent crosstalk. –UTP (Unshielded Twisted-Pair) – Most common network cable that comes in different categories for different uses. Categories 5e and 6. It is unshielded and more susceptible to interference. –STP (Shielded Twisted-Pair) – Same as UTP cable, but with extra foil to prevent outside noise from interfering with data on the cable.  Crosstalk – Where signals from one wire interfere with the signal on an adjacent wire. 15-12

13. 15-13 Network Cabling Network – Figure 15.6 UTP cable

14. 15-14 Copper Media  Plenum cable is treated with Teflon or fire retardant materials to reduce the risk of fire. It produces less smoke and is less toxic when burning.  PVC (polyvinyl chloride) – Cable with a plastic cable insulation or jacket. PVC is an alternative to Plenum cable.  Coaxial Cable (coax) – Type of copper network cabling used in older Ethernet networks as well as mainframe and minicomputer connections. Has a single, center wire conductor with an outer braided shield. 15-14

15. 15-15 Network Cabling Network – Figure 15.7 UTP wiring standards

16. 15-16 Network Cabling Network – Figure 15.8 RJ-45 pin 1 assignments

17. 15-17 Network Cabling Network – Figure 15.9 Coax cable with connector

18. 15-18 Fiber Media  Fiber-Optic Cable – An expensive network cabling made of plastic or glass fibers that carry data in the form of light pulses. Most often used to connect network devices such as switches together into a network backbone or for connecting networks together in a WAN. More secure and not affected by crosstalk or other interference like copper cable. –Single-Mode – A type of fiber-optic cabling that sends one light beam down the cable. Used for longer distance applications. –Multi-Mode – A type of fiber-optic cabling that allows multiple light signals to be sent along the same cable. Used for shorter distances.

19. 15-19 Network Cabling Network – Figure 15.11 Fiber-optic cable

20. 15-20 Access Methods There are standard rules by which computers on a network must adhere to in order to communicate. These rules are known as a common access method.  CSMA/CD (Carrier Sense Multiple Access/Collision Detect) – A common access method used by Ethernet.  Token Passing – The common access method used by fiber and Token Ring networks.  Token – Small data packet passed from one networked device to another in a ring topology.  CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) – A common access method used in wireless and Apple networks.

21. 15-21 Ethernet Issues and Concepts  Two types of transmissions used in Ethernet networks:  Half Duplex – Allows either the sending or the receiving device to send data, one device at a time. Data can travel both ways on a cable, but not at the same time.  Full Duplex – Allows the sending and receiving device to send data simultaneously. Data can travel both ways on a cable at the same time.

22. 15-22 Network Standards Network – Table 15.5 IEEE 802 standards

23. 15-23 OSI Model  OSI Model (Open Systems Interconnect) – A standard for information transfer across a network that was developed by the International Standards Organization. The model has 7 layers. –Physical Layer – Layer 1 of the OSI model that defines how bits are sent and received across the network without regard to their structure. –Data Link Layer – Layer 2 of the OSI model that accurately transfers bits across the network by encapsulating (grouping) them into frames. –Network Layer – Layer 3 of the OSI model that coordinates data movement between two devices on separate networks.

24. 15-24 OSI Model –Transport Layer – Layer 4 of the OSI model that determines details on how the data is sent, supervises the validity of the transmission, and defines protocol for structuring messages. –Session Layer – Layer 5 of the OSI model that manages communication and administrative functions between two network devices. –Presentation Layer – Layer 6 of the OSI model that defines how data is formatted, encoded, converted, and presented from the sender to the receiver, even though different computer language is used. –Application Layer – Layer 7 of the OSI model that defines how applications and the computer interact with a network, and negotiates services such as authentication, error recovery, and quality of service.

25. 15-25 OSI Model  ISP (Internet Service Provider) – A vendor that provides connection to the Internet.

26. 15-26 OSI Model Network – Figure 15.15 OSI model layers

27. 15-27 OSI Model Network – Figure 15.16 OSI peer communication

28. 15-28 OSI Model Network – Table 15.6 OSI model

29. 15-29 Networking Protocols  Network Protocol – Data communication language. –TCP/IP (Transport Control Protocol / Internet Protocol) – The most common network protocol used by most companies and home users as a standard protocol. Used to access the Internet. –IPX/SPX (Internetwork Packet Exchange/Sequenced Packet Exchange) – Original protocol used for connecting to Novell networks. Now TCP/IP is the standard protocol used. –NetBEUI (NetBIOS Enhanced User Interface) – Is a non- routable protocol used in simple networks.

30. 15-30 Network Addressing Network devices have to be able to identify each other in order to communicate across a network. They do this through various network addressing schemes.  MAC Address – A 48-bit unique number that is burned on the ROM chip of the NIC.  IP Address – It is a 32-bit binary number with groups of eight bits separated by a dot.

31. 15-31 IP Addressing  Network Number – Portion of an IP address that represents which network the computer is on.  Host Number – Portion of an IP address that represents the specific network device.  Broadcast Address – IP address used to communicate with all devices on a particular network.  Subnet Mask – A number the computer uses to determine which part of an IP address represents the network and which portion represents the host. 15-31

32. 15-32 Network Addressing Network – Figure 15.17 IP Addressing (network and host portions)

33. 15-33 IP Addressing Network – Figure 15.18 IP addressing (two network example)

34. 15-34 IP Addressing Network – Table 15.9 IP addressing information

35. 15-35 DUN (Dial-Up-Networking)  DUN (Dial-Up Networking) – A remote computer that dials into the Internet or a corporation using a modem.  PPP (Point-to-Point Protocol) – A connection-oriented that encapsulates data for transmission over various connection types.

36. 15-36 Dial-up Networking Network connections Network – Table 15.10

37. 15-37 Internet Software Once a connection is established to a remote network there are several program types that are useful for accessing data.  Browser – A program that views web pages across the Internet. The common browsers include Internet Explorer, Netscape Navigator, and Mozilla FireFox2.  Plug-in – An application, such as Macromedia Flash, designed to work with the browser.

38. 15-38 Wireless Networks Overview  Wireless Networks – Transmit data over air using either infrared or radio frequencies. Wireless networks operate at layers 1 and 2 of the OSI model.  Bluetooth – Wireless technology for PANs.  Piconet – A small network.

39. 15-39 Wireless Networks Types  There are two main types of wireless networks: –Ad hoc – Also known as peer-to-peer or IBSS (Independent Basic Service Set) – An ad hoc wireless network is when at least two devices such as two computers have wireless NICs. –Infrastructure – Wireless network that connects multiple wireless network devices through an Access Point.  There are three major types of wireless NICs: PC Card, USB, and PCI.  Access Point – Is similar to a network hub and connects wireless network devices.

40. 15-40 Wireless Networks Types  BSS (Basic Service Set) – Configuration when multiple devices connect to an access point.  ESS (Extended Service Set) – The network design when multiple access points connect to the same main network.  SSID (Service Set Identifier) – A set of 32 alpha numeric characters used to differentiate between wireless networks.  The channel ID (frequency) between the Access Point and the adapter must match for communication to occur.

41. 15-41 Wireless Networks Types 802.11b/g frequency channels Network – Table 15.11

42. 15-42 Wireless Network Standards  Modulation – When data is added to a carrier signal. IEEE 802.11 standards Network – Table 15.13

43. 15-43 Wired or Wireless NIC Installation  When installing a NIC, you must configure the following prior to connecting to the network:  Determine that an appropriate port, slot, or integrated wireless NIC is available.  Install the appropriate NIC drivers.  Assign the computer an appropriate name and a workgroup or domain name.  Configure the network protocol and client.

44. 15-44 Configuring Networking Some key terms to understand when configuring computers for networking are:  DHCP (Dynamic Host Configuration Protocol) – A method to automatically assign IP addresses to network devices from a pool of IP addresses. A computer requests an address from another device running DHCP, usually a server, receives it, and joins the network.  Default Gateway – The IP address of the Layer 3 device, such as a router, that is directly connected to its immediate network and acts as a doorway or director to other remote networks.

45. 15-45 Configuring Networking  DNS (Domain Name System) Server – Application on a network server that translates Internet names into IP addresses.  URL (Universal Resource Locator) – A method of accessing Internet resources by using a simple, easily remembered name assigned to an IP address.  WINS (Windows Internet Naming Service) Server – Keeps track of IP addresses assigned to a specific computer name. A user can type in a computer name to connect and the server will translate it to the computer’s IP address.

46. 15-46 Wired or Wireless NIC Installation  Before installing a wireless NIC, be sure to confirm the basic configuration settings for the wireless network.  Install the NIC by following the manufacturer’s instructions.  Configure the basic wireless network settings to begin communication on the network.

47. 15-47 Configuring Networking Network – Figure 15.41 Default gateway

48. 15-48 Network Troubleshooting Some commands that are useful to a technician when diagnosing network connection issues:  Ping – A command used to test TCP/IP communications and determine if a network path is available. You can type ping and either a domain name or IP address and connectivity to that device will be tested.  IPCONFIG – A command used with Windows XP and 2000 to see and modify the current IP settings.  NSLOOKUP – An NT, 2000, XP and 2003 Server troubleshooting tool that displays network domain names and their associated IP addresses.  Tracert – A command that displays the path a data packet takes through a network, thus allowing one to see where a fault occurs in larger networks.

49. 15-49 Network Troubleshooting Network – Figure 15.47 Sample network configuration

50. 15-50 Network Troubleshooting Network – Figure 15.48 IPCONFIG and IPCONFIG /ALL

51. 15-51 Network Terminology  Networking Terms and Acronyms To be Familiar With: BackboneBandwidthBaseband BroadbandE-mailFast Ethernet FDDI FrameFTP HTMLHTTPInfrared PacketPOPSNMP TCPTelnetUDP

52. 15-52 Sharing  Network share – A folder that has been shared and can be accessed from a remote computer.  UNC (Universal Naming Convention) – A standard way of naming computers and shared resources on a network. Used at the command prompt to obtain network shares. 1-52

53. 15-53 Email  SMTP (Simple Mail Transport Protocol) – is a protocol used for sending and receiving email. Settings for configuring email can be obtained from the network administrator or the ISP being used to connect to the Internet.  POP3 (Post Office Protocol) and IMAP (Internet Mail Access Protocol) are methods used to receive email to a person’s account.  MAPI (Messaging Application Programming Interface) – Microsoft’s proprietary alternative email protocol. 15-53