Copyright © 2005 Heathkit Company, Inc. All rights reserved. Unit 10 Networks

2 The basic components of a network: Connections (Physical Medium) Protocols (Common language) Services (Clients, Servers, and Files)

3 The Client is the computer requesting the use of a resource. May I have Worksheet-101? Client Server

4 The Server is the computer providing the resource. Sure, here it is! Worksheet-101 Client Server

5 In some networks, every computer acts as both Client and Server. Client & Server Client & Server Client & Server

6 Peer-to-Peer Network Client & Server Client & Server Client & Server

7 Peer-to-Peer Network No centralized data access. Security handled by assigning each resource a password.

8 Peer-to-peer works best with a a small number of computers.

9 One computer can act as server for several clients. Server Client

10 Client/Server Network Centralized data access. Centralized security. Centralized administration, record keeping, and control.

11 Larger networks require the client/server arrangement.

12 The Physical Medium is the channel the data travels between computers. Physical Medium Client Server

13 The Physical Media can be: Wire Fiber Optic Cable Wireless Link (RF or Infrared) Hardware devices such as network cards, hubs, routers, etc.

14 The common language is the Network Protocol. May I have Worksheet-101? Client Server Sure, here it is!

15 Protocol A signed document containing the record of the points on which agreement has been reached by negotiating parties. The code of ceremonial forms and courtesies accepted as proper and correct in official dealings.

16 In Networking, Protocols are: Agreements that describe how things work. Industry-wide frameworks that describe every aspect of communications between computers. Grouped together into Protocol Suites.

17 The main Protocol Suites: NetBEUI – Small Microsoft networks. SPX/IPX – Primarily Novell networks. TCP/IP – Must be used if the network is to connect to the Internet.

18 One of the most basic ways to classify networks is by their topology.

19 Topology refers to the way the computers in the network are connected to each other.

20 The most common topologies are: Bus Star Ring Mesh

21 Bus Topology “T” “Backbone”

22 Bus Topology A single cable interconnects all workstations. The cable is terminated at both ends. Terminator

23 Star Topology

24 Star Topology All workstations connect to a single central hub. Hub

25 Ring Topology

26 Ring Topology Backbone is a ring. Each workstation connects only to two other workstations.

27 Mesh Topology

28 Mesh Topology Router Net-1 Net-4 Net-3 Net-2

29 The Internet is an example of a Mesh topology. Internet

30 Another way of classifying networks is by their size or geographical span.

31 The most common size classifications are the: Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN)

32 The Local Area Network (LAN)

33 Metropolitan Area Network (MAN)

34 Wide Area Network WAN

Copyright © 2005 Heathkit Company, Inc. All rights reserved. Networking Components

36 Components Network Operating System Interface Cards Cables

37 Network Operating System (NOS) vs. desktop Operating System (OS)

38 NOS provides improved security User-level Security Server authenticates: –User name –User password –User location Server determines which resources the user may access. Simplifies security for the user.

39 The NOS allows sensitive resources to be maintained in a centralized/secure location.

40 The NOS provides improved performance. Client is relieved of the burden of server Server can be optimized Adds administration and management capabilities.

41 The NOS provides better administration. Centralized security Centralized data Consistent policies Administrative tools Accountability

42 The NOS allows scalability The client/server network grows gracefully. A server may handle over 50 clients. Additional servers can be added. Specialized servers –File server –Print server –Communications Server

43 Disadvantages of the NOS More expensive More complex Requires administration.

44 Major Network Operating Systems Unix Novell NetWare Windows NT Server

45 Unix Multitasking, Multi-user OS Influential in evolution of the Internet Uses TCP/IP Clients communicate with Server using Terminal Emulation

46 Linux Smaller, easier to use version of Unix Easily adapted to individual computers or as server in a small network Uses the command line as the user interface. Offered with a graphical user interface.

47 Novell’s NetWare Text-based operating system Supports all Windows-based client computer operating systems IPX/SPX is the primary NetWare protocol

48 Windows NT 32-bit network operating system First to use a graphical user interface Not as feature-rich as Unix and NetWare Supports a wide range of network clients

49 The Network Interface Card is also called: The Network Card The Network Adapter The Network Adapter Card The NIC

50 The NIC is the main interface between the computer and the network cable.

51 Parallel data into serial data. CPU Memory Computer NIC Cable

52 Considerations when selecting the NIC: Type of cable connection Type of Address/Data Bus The method used to configure the card.

53 The NIC must match the cable. RJ-45 BNC

54 RJ-45 Connector

55 The NIC must match the Address/Data Bus of the computer. ISA PCI

56 Installing the NIC in the computer. NIC installed inside the computer. Normally plugs into a bus slot. Some are built right into the motherboard. Plug-in boards must be configured correctly.

57 NIC Configuration Methods Plug-and-Play EEPROM Jumper pins

58 Preparing to Install the NIC Ensure there is an open bus slot. Ensure the adapter is compatible. Ensure there are system resources available. Ensure all installation items are available. Ensure all software is available.

59 Installing the NIC Hardware Configure the NIC to available resources. Use a ground strap. Remove cover from the computer. Remove rear panel slot cover plate. Remove card from its antistatic bag and immediately plug it into motherboard. Secure card slot cover plate to computer.

60 Installing the NIC Software Loading the device driver used by the NIC. Loading any utilities supplied with the NIC.

61 NIC Device Driver Supports communication between the NIC and OS. Automatically installed and configured if both NIC and OS support PnP. In other cases, driver loaded from floppy or CD supplied with NIC.

62 A more recent device driver may be available at the website of the NIC manufacturer.

63 Troubleshooting the NIC Is NIC talking to the motherboard? Is the NIC working internally? Is the NIC communicating with the external network?

64 LEDs Link Activity

65 Twisted-Pair Cable UTP—Unshielded Twisted-Pair STP—Shielded Twisted-Pair

66 Twisted-Pair Cable STP UTP Foil Shield Foil Shield Wire Braid Shield Wire Braid Shield Foil Shield Foil Shield

67 10BaseT Ethernet uses Unshielded Twisted Pair (UTP) cable.

68 RJ-45 Connector Strain Relief Crimp Contacts Latch Wires

69 Twisted-Pair Advantages UTP is inexpensive. Workstations isolated from each other by central hub. Easy to add workstations to segment. Easier to route than coaxial cable. Easier to troubleshoot than coaxial cable network.

70 Twisted-Pair Disadvantages UTP cable is susceptible to RFI/EMI. Suffers crosstalk between wire pairs. Poor conductor; attenuates signal more quickly than coax. Maximum segment length half of coax. STP cable more expensive than UTP cable or coax. Difficult to work with shielding.

71 EIA/TIA Cable Categories Category 1—Voice-grade UTP phone Category 2—Data-grade UTP, 4 Mbps Category 3—Data-grade UTP, 10 Mbps Category 4—Data-grade UTP, 16 Mbps Category 5—Data-grade UTP, 100 Mbps

72 Category 3 Cable Common data-grade cable. Four unshielded twisted-pair wires. Transmission rates up to 10 Mbps.

73 Category 5 Cable Data-grade cable. Official transmission rates up to 100 Mbps. Four unshielded twisted-pair wires.

74 Two Bus Technologies: 10Base5 or Thicknet 10Base2 or Thinnet

75 Coaxial Cable Characteristics Sleeve Wire Braid DielectricCenter Conductor Foil RG-8 Thicknet Cable RG-58 Thinnet Cable

76 Coax Advantages Resistant to RFI. Good conductor. Longer network segments. Thinnet: easy/inexpensive workstation interconnection. Thicknet: stronger, more durable than any other network cable.

77 Coax Disadvantages Each segment must be terminated. Break in cable disables entire segment. Difficult to add workstations to a thinnet segment. Thicknet: difficult to use, heavy shield braid and foil. Thicknet: requires special piercing tap and transceiver.

78 What’s in a name? 10Base5 10Base2

79 The number on the left is the speed of the LAN. 10 Base 5 10 Base 2 Speed in Megabits Per Second Speed in Megabits Per Second

80 The number on the right is the length of the LAN segment. 10 Base 5 10 Base 2 Length of Segment in Hundreds Of Meters Length of Segment in Hundreds Of Meters

81 The word in the middle signifies the type of signal. 10 Base 5 10 Base 2 Type of Signal

82 Baseband Broadband Signal 1 Signal 2 Signal 3

83 RG-58, 10Base2, or Thinnet Cable RG-8, 10Base5, or Thicknet Cable

84 The RG-58’s lighter shield still provides good protection against electrical noise.

85 Fiber Optic Cables

86 Cable Construction

87 Fiber end-view

88 The Glass Fiber

89 ST connector

90 ST Connector

Copyright © 2005 Heathkit Company, Inc. All rights reserved. LAN Communication

92 LAN Technologies: Ethernet Token Ring ARCnet LocalTalk

93 Ethernet Developed by Xerox in early ’70s. Has become most popular networking technology in use today. A variety of speeds and cabling options have evolved. It is fast, inexpensive, and flexible. It continues to evolve. Majority of new networks use Ethernet.

94 Networking is all about sending data from one location to another. May I have Worksheet-101? Sure, here it is! PC-1 PC-2

95 The CPU routinely sends data from one place to another. CPU

96 But when multiple computers are involved, a new series of problems arise. PC-1 PC-2PC-3PC-4PC-5

97 How do you keep all the computers from transmitting at the same time? PC-1 PC-2PC-3PC-4PC-5

98 Is this for me? PC-1 PC-2PC-3PC-4PC-5

99 Who sent this? PC-1 PC-2PC-3PC-4PC-5

100 PC-1 PC-2PC-3PC-4PC-5 Ah, it’s from PC-1. Gee, I wonder if it is correct.

101 PC-1 PC-2PC-3PC-4PC-5 Here’s the ten gigabyte folder you wanted!

102 Large files are broken into manageable chunks called packets. Large File Packets

103 How do you keep two computers from transmitting at the same time? PC-1 PC-2PC-3PC-4PC-5

104 Carrier Sense Multiple Access/ Collision Detection (CSMA/CD)

105 Carrier Sense Each computer attached to the network examines the cable before transmitting. If it senses traffic on the cable, it waits until the traffic clears before transmitting.

106 Multiple Access All computers on the network have equal access to the cable. A lowly desktop has the same access as the Windows NT Server. Access is on a first-come, first-served basis. The only consideration is: “Is someone else using the cable?”

107 Collisions still happen PC-1 PC-2PC-3PC-4PC-5

108 The computers involved in the collision detect the collision. PC-1 PC-2PC-3PC-4PC-5 Wow! That’s not what I said!

109 The computers involved in the collision back off for a random length of time. PC-1 PC-2PC-3PC-4PC-5 I’ll back off for “x”Microseconds I’ll try “y” Microseconds.

110 Collisions are a natural characteristic of Ethernet. PC-1 PC-2PC-3PC-4PC-5