Computer Network Technology Introduction PDF

2024-2025 Fall Semester Computer Network Technology Introduction  Agenda What is the network? Components of a computer network Benefits of computer network Network devices Network category 2  What is the network? A...

2024-2025 Fall Semester Computer Network Technology Introduction  Agenda What is the network? Components of a computer network Benefits of computer network Network devices Network category 2  What is the network? A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are made up of telecommunication network technologies, based on physically wired, optical, and wireless radio-frequency methods that may be arranged in a variety of network topologies. 3  Components of a computer network 1.Two or more computers 2.Cables as links between the computers 3.A network interfacing card(NIC) on each computer 4.Switches 5.Software called operating system(OS) 4  Benefits of computer network Increase speed Reduced cost Improved security Centralized software managements Electronic mail Flexible access 5  Network Devices 6  Network Devices: Server A server Is a device that provides functions or services for clients 7  Network Devices: Client Client-server network examples 8  Network Devices a client is any computer hardware or software device that requests access to a service provided by a server A server is a computer program or device that provides a service to another computer program and its user, also known as the client. 9  Network Devices: Switch Cairo Branch Alex. Branch Switch is a network device whose responsibility is to Connect Network devices 10  Network Devices: Router Cairo Branch(server) Alex. Branch(client) Router is a device which directs the packets or data to their destination 11  Network Categories 12  Network Categories: Connection type  Types of connections Point to point A dedicated link is provided between two devices Multipoint More than two specific devices share a single link The medium to make a connection can be either microwave-based 13  Network Categories: Connection type Simplex, half-duplex, full-duplex The communication between two nodes can be either simplex, half-duplex or full duplex. In the simplex mode of communication, only one node can send data. In half-duplex, both devices (nodes) can send data but one at a time. In full-duplex, both devices can send data at a time. When you change television channels by infrared remote control, you are establishing a point-to- point connection between the remote control and the television's control system. 14  Network Categories: Topology Mesh Topology A fully connected mesh network, therefore, has [n (n-1) / 2] physical channels to link it devices 15  Network Categories: Topology Mesh Topology The main disadvantages of a mesh topology are: Difficult installation and reconfiguration because every device must be connected to every other device. The bulk of the wiring can be greater than the available space can accommodate. The hardware required to connect each link can be expensive 16  Network Categories: Topology Star topology The advantages of star topology are: 1. Less expensive than a mesh topology. 2. Easy to install. 3. Robustness. If one link fails, only that link is affected. 4. Easy fault identification and fault isolation. As long as the hub is working, it can be used to 17 monitor link problems and bypass defective  Network Categories: Topology Star topology The disadvantages of the star topology are: 1. Any fault occur to the central controller will drop down the entire network. 2. Although the star needs less cabling than mesh, it still needs more cables than ring and tree topology. 18  Network Categories: Topology Bus Topology The preceding examples all describe point-to-point configurations A bus topology on the other hand, is multipoint. One long cable acts as a backbone to link all the devices in the network. Nodes are connected to the bus cable by drop lines and taps. A drop line is a connection that runs between the device and the main cable, a tap is a connector that splices into the main. As a signal travels along the backbone, some of its energy is transformed into heat. Therefore, it becomes weaker and weaker the farther it has to travel. For this reason, there is a limit on the number of taps a bus can support and on the distance between those taps 19  Network Categories: Topology Bus Topology The advantages of a bus topology are: Ease of installation. Backbone cables can be laid along the most efficient path, then connected to the nodes by drop lines of various lengths. Use less cabling than mesh, star, and tree topologies disadvantages are: Difficult reconfiguration and fault isolation. A fault or break in the bus cable stops all transmission, even between devices on the same side of the problem. 20  Network Categories: Topology Ring Topology In a ring topology, each device has a dedicated point-to-point line configuration only with the two devices on either side of it. A signal is passed along the ring in one direction, from device to device, until it reaches its destination. Each device in the ring incorporates a repeater. When a device receives a signal intended for another device, its repeater regenerates the bits and passes them along 21  Network Categories: Topology Ring Topology The advantages of ring topology are: 1. Relatively easy to install and reconfigure. 2. Addition or deletion of a device requires moving only two connections. 3. Fault isolation is simplified. 4. The disadvantage of the ring topology is that a break in the ring (such as a disabled station) can disable the entire network, and it is a one-way data flow. 22  Network Categories: Topology Tree Topology A Tree topology is a type of network topology that resembles a tree. In a tree topology, there is one central node (the “trunk”), and each node is connected to the central node through a single path 23  Network Categories: Topology Hybrid Topology Often a network combines several topologies as sub-networks linked together in a larger topology. For instance, one department of a business may have decided to use a bus topology while another department has a ring. The two can be connected to each other via a central controller in a star topology 24  Network Categories: Distance 1- PAN A PAN provides data transmission among devices such as computers, smartphones, tablets , and personal digital assistants. PANs can be used for communication among the personal devices themselves, or for connecting to a higher- level network and the Internet where one master device takes up the role of a gateway 25  Network Categories: Distance 2- LAN A local area network is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. 26  Network Categories: Distance Lan: peer to peer P2P is an information technology (IT) infrastructure allowing two or more computer systems to connect and share resources without requiring a separate server or server software Workplaces may set up a P2P network by physically connecting computers into a linked system 27or creating a virtual network.  Network Categories: Distance LAN : Client-Server Network In a client server network, there are clients and servers. A client can be a device or a program. It helps the end users to access the web. Some examples of clients are desktop, laptops, smartphones, web browsers, etc. A server is a device or a program that responds to the clients with the services. It provides files, databases, web pages, shared resources according to its type. 28