Computer networking


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  • Computer networking

    1. 1. Prepared by Abegail T. Soñas January 2012
    2. 2. I. Introduction II. Network Hardware a. (By service) Two Main Types b. (By scope/scale) Area Network III. Types c. (By physical communication scheme) Network Topologies IV. OSI Model a. Network BandwidthV. Network Performance b. Network Throughput c. Network LatencyReferences & Video Link
    3. 3. History DefinitionApplications
    4. 4. INTRODUCTION  Networking began its infancy in the mid - 1960’s by the US Department of Defense (DoD).  The original intention of networking was being developed to withstand a nuclear war.
    5. 5. INTRODUCTION  Networks are collections of computers, software, and hardware that are all connected to help their users work together.
    6. 6. INTRODUCTION A network connects computers by means of • cabling systems, • specialized software, and • devices that manage data traffic.
    7. 7.  Resource Sharing • Hardware (computing resources, disks, printers) • Software (application software) Information Sharing • Easy accessibility from anywhere (files, databases) • Search Capability (WWW) Communication • Email • Message broadcast Remote computing • Distributed processing
    8. 8.  The distribution of applications and business logic across multiple processing platforms. • Distributed processing implies that processing will occur on more than one processor in order for a transaction to be completed. In other words, processing is distributed across two or more machines and the processes are most likely not running at the same time, i.e. each process performs part of an application in a sequence. • Often the data used in a distributed processing environment is also distributed across platforms.
    9. 9. Workstation Network Distribution(Network Cables | Hub | Router)
    10. 10. NETWORK HARDWARE  In a network, computers and optional other devices are connected to share resources. • When a computer or device A is requesting a resource from another computer or device B, the item A is referred to as a client.
    11. 11. NETWORK HARDWARE  Because all or most items that are part of a network live in association or cooperation, almost any one of them can be referred to as a client.  Based on this, there can be different types of clients. • The most regularly used of them is referred to as a workstation.
    12. 12. NETWORK HARDWARE  a computer that optimizes the user interface, relying on servers to handle the more mundane tasks associated with • application and file storage, • network administration, • security, and • other critical functions.
    13. 13. NETWORK HARDWARE  is a computer on which a person performs everyday regular assignments.
    14. 14. NETWORK HARDWARE a computer that supplies data or resources to other machines on a network
    15. 15. NETWORK HARDWARE 1TB expandable storage for $400
    16. 16. NETWORK HARDWARE The server room at the new Facebook data center in Prineville, Oregon, featuring a hot aisle containment system.
    17. 17. NETWORK HARDWARE  This one is shown coupled together with a second open frame rack.
    18. 18. NETWORK HARDWARE  Building a network consists partly of connecting the computers  One way to do this is to use cables.
    19. 19. NETWORK HARDWARE  NETWORK CABLES • Cable is used to connect computers. • In our network, we will use Category 5 cable RJ- 45. The ends of the cable appear as follows:
    20. 20. NETWORK HARDWARE  NETWORK CABLES • Category 5 cable RJ-45  Registered jack 45  standard type of connector for network cables such as those used in Ethernet networks  standard connector utilized on 4-pair (8-wire) UTP (Unshielded Twisted Pair) cable
    21. 21. NETWORK HARDWARE  HUB • A hub is rectangular box that is used as the central object on which computers and other devices are connected. • To make this possible, a hub is equipped with small holes called ports.
    22. 22. NETWORK HARDWARE  HUB • A hub can be equipped with 4, 5, 12, or more ports
    23. 23. NETWORK HARDWARE  ROUTER: Wired or Wireless • Like a hub, a router is another type of device that acts as the central point among computers and other devices that are part of a network.  A router can be considered a little "intelligent" than the hub.
    24. 24. NETWORK HARDWARE  ROUTER: Wired or Wireless • A router can be considered a little "intelligent" than the hub. Wireless Wired
    25. 25. NETWORK HARDWARE  NETWORK CARD: Wired or Wireless • In order to connect to a network, a computer must be equipped with a device called a network card. • A network card  or a network adapter, also called a network interface card, or NIC  allows a computer to connect to the exterior.
    26. 26. NETWORK HARDWARE  NETWORK CARD: Wired or Wireless • A wired network card looks like a printed circuit board with some objects "attached" or "glued" to it
    27. 27. NETWORK HARDWARE  NETWORK CARD: Wired or Wireless • A wireless NIC appears as its wired counterpart
    28. 28. BY SERVICE Peer-to-Peer(Definition | Network Setup | Benefits | Limits) Client/Server (Definition | Benefits | Limits)
    29. 29. 2 MAIN TYPES A peer-to-peer network • allows any user to share files with any other user and • doesnt require a central, dedicated server. A network is referred to as peer-to-peer if most computers are similar and run workstation operating systems
    30. 30. 2 MAIN TYPES  Ina peer-to-peer network, each computer holds its files and resources.  Other computers can access these resources but a computer that has a particular resource must be turned on for other computers to access the resource it has. • For example, if a printer is connected to computer A and computer B wants to printer to that printer, computer A must be turned On.
    31. 31. 2 MAIN TYPES
    32. 32. 2 MAIN TYPES
    33. 33. 2 MAIN TYPES  Physical Connection  Wired Networking • Uses router to connect the computers
    34. 34. 2 MAIN TYPES  Physical Connection  Wireless Networking • Uses router to connect the computers
    35. 35. 2 MAIN TYPES  BENEFITS  Inexpensive to set up. • It uses the built in networking capabilities of Windows XP Professional (or Vista Business), so no special software is needed. • It allows for file and printer sharing, and can be an adequate choice for a very small office.
    36. 36. 2 MAIN TYPES  LIMITS  Network and data security are weak.  Files are not centralized, so getting a back up of all critical files is more difficult.
    37. 37. 2 MAIN TYPES  LIMITS  Ongoing tasks like anti-virus scanning and Windows updates are localized on each machine. • Updating virus definitions and patches has to be done manually at each machine, which is time consuming.
    38. 38. 2 MAIN TYPES  uses one or more dedicated machines (the server) to share the files, printers, and applications
    39. 39. 2 MAIN TYPES
    40. 40. 2 MAIN TYPES
    41. 41. 2 MAIN TYPES  Client/server describes the relationship between two computer programs in which one program, • the client, makes a service request from another program, • the server, which fulfills the request.  In a network, the client/server model provides a convenient way to interconnect programs that are distributed efficiently across different locations.
    42. 42. 2 MAIN TYPES  Computer transactions using the client/server model are very common.  For example, to check your bank account from your computer, a client program in your computer forwards your request to a server program at the bank. • That program may in turn forward the request to its own client program that sends a request to a database server at another bank computer to retrieve your account balance. • The balance is returned back to the bank data client, which in turn serves it back to the client in your personal computer, which displays the information for you.
    43. 43. 2 MAIN TYPES  BENEFITS  The server • stores all of the shared files for each user  Files and resources are centralized • runs the file backups • manages user security and insures all users who access the network are authorized to do so  Username and password
    44. 44. 2 MAIN TYPES  BENEFITS  The server • manages printer sharing and acts as a central repository for the printer drivers and settings • Manages other common tasks such as internet access, email routing, Windows updating, and anti-virus definition management
    45. 45. 2 MAIN TYPES  BENEFITS  The server can also • share software applications out to multiple users • provide for an “Intranet”, an internal website which holds shared company information such as news announcements, HR policies, training documents, and more
    46. 46. 2 MAIN TYPES  BENEFITS  In short, this network • provides for easier network administration, and • provides a much more robust environment in which provide secure and manageable access to company data.
    47. 47. 2 MAIN TYPES  LIMITS A server based computer network is more expensive to implement. • Server computers are powerful machines with built-in redundancy and other hardware to provide data safety. • Hence, they cost much more than a simple desktop computer.
    48. 48. 2 MAIN TYPES  LIMITS  The server network software is also much more • powerful, • complicated, and • must be installed correctly to run all of the required tasks,  and so the cost is higher for both the software and installation charges.
    49. 49. 2 MAIN TYPES  LIMITS  Theserver is a critical point of failure. If it goes down, the entire network comes to a halt. • This drawback can be minimized with the installation of redundant drives in the server (so that if one fails, the others will still be working), • and even a second server that can take over if the primary server fails completely. • Cost then becomes the only issue.
    50. 50. BY SCOPE / SCALE LAN WAN
    51. 51. TYPES BY SCOPE / SCALE  One way to categorize the different types of computer network designs is by their scope or scale.  For historical reasons, the networking industry refers to nearly every type of design as some kind of area network.
    52. 52. TYPES BY SCOPE / SCALE  Stands for Local Area Network  Usually denotes a network of computers which are fairly close together, say in the same building or office.
    53. 53. TYPES BY SCOPE / SCALE  Stands for Wide Area Network  Usuallyconnect local area networks which are separated by great distances
    55. 55. TYPES BY PHYSICAL COMMUNICATION SCHEME  Thenetwork topology defines the way in which computers, printers, and other devices are connected. A network topology describes the • layout of the wire and devices • as well as the paths used by data transmissions.
    56. 56. TYPES BY PHYSICAL COMMUNICATION SCHEME  physical communication scheme used by connected devices  More complex networks can be built as hybrids of two or more of these basic topologies.
    58. 58. TYPES BY PHYSICAL COMMUNICATION SCHEME Bus topology allows information to be directed from one computer to the other. Lots of binary collision. Commonly referred to as a linear bus, all the devices are connected by one single cable.
    59. 59. TYPES BY PHYSICAL COMMUNICATION SCHEME Star topology is the most common type used. All computers are attached to a hub. Less collisions and most efficient. The star topology is the most commonly used architecture in Ethernet LANs. When installed, the star topology resembles spokes in a bicycle wheel.
    60. 60. TYPES BY PHYSICAL COMMUNICATION SCHEME Larger networks use the extended star topology also called tree topology. When used with network devices that filter frames or packets, like bridges, switches, and routers, this topology significantly reduces the traffic on the wires by sending packets only to the wires of the destination host.
    62. 62. TYPES BY PHYSICAL COMMUNICATION SCHEME A frame travels around the ring, stopping at each node. If a node wants to transmit data, it adds the data as well as the destination address to the frame. The frame then continues around the ring until it finds the destination node, which takes the data out of the frame. A disadvantage of a token ring is if one computer is broken or down, the message cannot be passed to the other computers.
    63. 63. TYPES BY PHYSICAL COMMUNICATION SCHEME The mesh topology connects all devices (nodes) to each other for redundancy and fault tolerance. It is used in WANs to interconnect LANs and for mission critical networks like those used by banks and financial institutions. Implementing the mesh topology is expensive and difficult.
    64. 64. OSI MODEL  Open Systems Interconnection  TheOSI model defines internetworking in terms of a vertical stack of seven layers.
    65. 65. OSI MODEL  The OSI model was introduced in 1984.  Although it was designed to be an abstract model, the OSI model remains a practical framework for todays key network technologies like Ethernet and protocols like IP.
    66. 66. OSI MODEL
    67. 67. OSI MODEL  Modular approach to network functionality  Example: Application Application-to-application channels Host-to-host connectivity Link hardware
    68. 68. OSI MODEL  Module in layered structure  Set of rules governing communication between network elements (applications, hosts, routers)  Protocols define: • Interface to higher layers (API) • Interface to peer  Format and order of messages  Actions taken on receipt of a message
    69. 69. OSI MODEL  Eachlayer relies on services from layer below and exports services to layer above  Interface defines interaction  Hidesimplementation - layers can change without disturbing other layers (black box)
    70. 70. OSI MODEL 1) Physical : how to transmit bits 2) Data link : how to transmit frames 3) Network : how to route packets 4) Transport : how to send packets end2end 5) Session : how to tie flows together 6) Presentation: byte ordering, security 7) Application : everything else
    71. 71. OSI MODEL Application Presentation Session Transport Network Data Link Physical Host Switch Router Host
    72. 72. BandwidthThroughput Latency
    73. 73. NETWORK PERFORMANCE  supporteddata rate of a network connection or interface  refers to the capacity • since having a higher capacity means you are able to get more data through in the same time period, the end result is that the time taken for your to view and download your content is shorter
    74. 74. NETWORK PERFORMANCE  actual data rate
    75. 75. NETWORK PERFORMANCE  Latencyrefers to a data packets round-trip time (RTT) • i.e. the time it takes a network packet to travel from source host to its destination and back.  end-to-end rate of data transmission • i.e. the amount of data that actually gets transmitted from your PC, through the Internet to the web server and back in a single unit of time. This
    76. 76. NETWORK PERFORMANCE  Network performance, i.e. its speed and capacity, are defined by bandwidth and latency. • Bandwidth and latency are connected: bandwidth latency increases if too little bandwidth is available.  In order to ensure good network performance, it is therefore important to monitor both bandwidth and latency.
    77. 77. NETWORK PERFORMANCE  Ingeneral, bandwidth and throughput get a lot of attention, while latency gets little. • Yet latency considerations are very important for many real-time applications  such as streaming audio and video  and interactive gaming.
    78. 78.  http://www.sensible-computer-
    79. 79.  How Wifi Works - YouTube • How the Internet Works - YouTube • Computer Networking Tutorial 1 - YouTube • Computer Networking Tutorial - 4 - OSI Model Physical Layer • Bandwidth vs. Throughput - YouTube •