Computer Networks css presenations .pptx

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1. Computer Networks

2. Computer Networking A NETWORK is two or more computers connected to share resources. In general term, network can refer to any interconnected group or system. In other words, network is a method of sharing information between two systems. Computers are networked according to certain protocols, such as TCP/IP, which are the rules or standards that allow computers on the network to communicate with one another.

3. Types of Network Networks can be categorized by several methods, including the technology used and the size of the network. When networks are categorized by size or physical area they cover, these are the categories used: PAN-PERSONAL AREA NETWORK LAN-LOCAL AREA NETWORK WLAN-WIRELESS LOCAL AREA NETWORK CAN-CAMPUS AREA NETWORK MAN-METROPOLITAN AREA NETWORK WAN-WIDE AREA NETWORK GAN-GLOBAL AREA NETWORK VPN-VIRTUAL PRIVATE NETWORK

4. Types of Network Personal Area Network (PAN) – consists of personal devices communicating at close range such as a cell phone and notebook computer. PANs can use wired connections (such as USB or FireWire) or wireless connections (such as Bluetooth or infrared). The reach of a PAN is typically at least about 20-30 feet (approximately 6-9 meters), but this is expected to increase with technology improvements.

5. Types of Network Local Area Network (LAN) – covers a small local area such as a home, office, other building, or small group of buildings. LANs can use wired (most likely Ethernet) or wireless (most likely Wi-Fi, also called 802.11) technologies. A LAN is used for workstations, servers, printers, and other devices to communicate and share resources.

6. Types of Network Wireless LAN (WLAN) – covers a limited geographical area and is popular in places where networking cables are difficult to install, such as outdoors, in public places, and in homes that are not wired for networks. They are also useful in hotel rooms.

7. Types of Network Campus Area Network (CAN) – a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. It can be considered one form of a metropolitan area network, specific to an academic setting.

8. Types of Network Metropolitan Area Network (MAN) – covers a large campus or city. (A small MAN is sometimes called a CAN or campus area network.) Network technologies used can be wireless (most likely LTE or WiMAX) and/or wired (for example, Ethernet with fiber-optic cabling).

9. Types of Network Wide Area Network (WAN) – covers a large geographical area and is made up of many smaller networks. The best-known WAN is the Internet. Some technologies used to connect a single computer or LAN to the Internet include DSL, cable Internet, satellite, cellular WAN, and fiber optic.

10. Types of Network Global Area Network (GAN) – specification is in development by several groups, and there is no common definition. In general, however, a GAN is a model for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is "handing off" the user communications from one local coverage area to the next.

11. Types of Network Virtual Private Network (VPN) – a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires. The data link layer protocols of the virtual network are said to be tunneled through the larger network when this is the case. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption.

12. Network Topology The physical arrangement of the connections between computers is called the network topology or the physical topology. Types of Network Topology Mesh Network Ring Network Bus Network Star Network

13. Types of Network Topology Mesh Network - In a mesh network, each node (a computer or other device that uses the network) on the network is responsible for sending and receiving transmissions to any other node to which it wants to communicate without a central point of communication. When each node connects to every node on the network, the network is called a fully connected mesh topology.

14. Types of Network Topology Ring Network - In a ring network, nodes form a ring. Really old IBM Token Ring networks worked by passing a token around the ring. This topology is seldom used today because one down computer or a broken cable can halt all communication on the ring.

15. Types of Network Topology Bus Network - Another old topology is a bus network whereby all computers are connected in a sequential line. The bus network worked better than a ring network because one down computer does not prevent other computers from communicating on the bus. However, a broken cable can still bring down an entire bus network.

16. Types of Network Topology Star Network - A star network uses a centralized device to manage traffic on the network. This centralized device can be a switch or hub that offers multiple network ports or wireless connections. (Hubs are not as efficient as switches and no longer sold even though you might still see a hub in use.) Star networks are almost totally used for LANs today. An advantage of a star network is that one down computer or one broken cable does not bring down the entire network.

17. For every job there is the right tool. Make sure that you are familiar with the correct use of each tool and that the correct tool is used for the current task. Skilled use of tools and software makes the job less difficult and ensures that tasks are performed properly and safely. Using tools properly helps prevent accidents and damage to equipment and people. List of Tools for Networking Loopback Plug LAN Tester Network Multimeter Wire Stripper Crimper/Crimping Tool Punchdown Tool

18. Tools for Networking Loopback Plug – can be used to test a network cable or port. To test a port or cable, connect one end of the cable to a network port on a computer or another device, and connect the loopback plug to the other end of the cable. If the LED light on the loopback plug lights up, the cable and port are good.

19. Tools for Networking LAN Tester – is used to test a cable to find out if it is good or to find out what type of cable it is if the cable is not labeled. You can also use a cable tester to locate the ends of a network cable in a building. A cable tester has two components, the remote and the base.

20. Tools for Networking Network Multimeter – is a multifunctional tool that can test cables, ports, and network adapters.

21. Tools for Networking Wire Stripper – is used to build your own network cable or repair a cable. Use the wire stripper to cut away the plastic jacket or coating around the wires inside a twisted-pair cable so that you can install a connector on the end of the cable.

22. Tools for Networking Crimper/Crimping Tool – is used to attach a terminator or connector to the end of a cable. It applies force to pinch the connector to the wires in the cable to securely make a solid connection.

23. Tools for Networking Punchdown Tool – also called an impact tool, is used to punch individual wires in a network cable into their slots in a keystone RJ-45 jack that is used in an RJ-45 wall jack.

24. Local Area Network – a computer network that interconnects computers within a limited area such as a home, school, computer laboratory, or office building, using network media. Using this network, we can use peripheral connected to one computer such as printer to print files or documents from another computer. Materials Used for LAN Cabling UNSHIELDED TWISTED PAIR (UTP) CABLE HUB SWITCH BRIDGE ROUTER RJ45 CONNECTOR

25. Materials for LAN Cabling Unshielded Twisted Pair (UTP) Cable – most common cable used in computer networking. Number of twisted-pair wires are often grouped together and enclosed in a protective sheath to form a cable.

26. Materials for LAN Cabling Hub – enables computers on a network to communicate. Each computer plugs into the hub with an ethernet cable, and information sent from one computer to other passes through the hub.

27. Materials for LAN Cabling Switch – works the same way as the hub but they can identify the intended destination of the information they receive, so they send that information to only the computers that are supposed to receive it. Switch can receive and send information at the same time.

28. Materials for LAN Cabling Bridge – is a computer networking device that builds the connection with the other bridge networks which use the same protocol.

29. Materials for LAN Cabling Router – enables computers to communicate and they can pass information between two networks such as between your home network and the internet.

30. Materials for LAN Cabling RJ45 Connector – registered jack 45, is an eight-wire connector used to connect computers to category 5 unshielded twisted pair cables in a network.

31. Advantages of Networking File Sharing - The major advantage of a computer network is that is allows file sharing and remote file access. Resource Sharing - Resource sharing is also an important benefit of a computer network. Increased Storage Capacity - As there is more than one computer on a network which can easily share files, the issue of storage capacity gets resolved to a great extent. A standalone computer might fall short of storage memory, but when many computers are on a network, memory of different computers can be used in such case. One can also design a storage server on the network to have a huge storage capacity. Increased Cost Efficiency - There are many software available in the market which are costly and take time for installation. Computer networks resolve this issue as the software can be stored or installed on a sy

32. Disadvantages of Networking Security Issues - One of the major drawbacks of computer networks is the security issues involved. Rapid Spread of Computer Viruses - If any computer system in a network gets affected by computer virus, there is a possible threat of other systems getting affected too. Expensive Set Up - The initial set up cost of a computer network can be high depending on the number of computers to be connected. Dependency on the Main File Server - In case the main File Server of a computer network breaks down, the system becomes useless.

33. 2 Types of LAN Cables Straight-Through Cable – is the most common type of cable and is used for connecting your computer to your network. It is used to connect device of different types, such as a computer to a network switch or hub. Cross-over Cable – used to connect computing device together directly. It 21 is most often used to connect two devices of the same type such as two computer or two switches to each other.

34. Steps in Making Connections Step 1: Strip cable end ✓ Strip 1 – 1½” of insulating sheath. ✓ Avoid cutting into conductor insulation. Step 2: Untwist wire ends ✓ Sort wires by insulation colors. Step 3: Arrange wires ✓ TIA/EIA 568A: GW-G OW-Bl BlW -O BrW -Br ✓ TIA/EIA 568B: OW-O GW-Bl BlW -G BrW -Br Step 4: Trim wires to size ✓ Trim all wires evenly. ✓ Leave about ½” of wires exposed

35. Steps in Making Connections Step 5: Attach connector ✓ Maintain wire order, left-to-right, with RJ45 tab facing downward. Step 6: Check ✓ Make sure that all wires extend to end and that the sheath well inside connector. Step 7: Crimp ✓ Squeeze firmly to crimp connecter onto cable end. Step 8: Repeat Steps ✓ Repeat Step 1 to Step 7 to the other end of cable. Step 9: Test ✓ Check if the cable is working

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