Computer Skills Lecture 7 PDF

Computer Skills Eng. Rafat Yousef Alhakimi RE&AI – Level 1 lecture 7 Network Fundamentals When we communicate, we are sharing information. This sharing can be local or remote. The term telecommunication, which includes telephony, telegraph, and television, means comm...

Computer Skills Eng. Rafat Yousef Alhakimi RE&AI – Level 1 lecture 7 Network Fundamentals When we communicate, we are sharing information. This sharing can be local or remote. The term telecommunication, which includes telephony, telegraph, and television, means communication at a distance. Data communications are the exchange of data between two devices via some form of transmission media. Five components of data communication : 1- Sender. 2- Receiver. 3- Message. 4- Transmission Medium. 5- Protocol. Network Fundamentals Transmission Modes in Computer Networks... Simplex Mode : One way transmission only one can send other can receive. We cannot send a message back to the sender. Half duplex Mode: In half-duplex mode, data is transmitted in both directions, but only one device can transmit data at a time. That means the devices take turns transmitting and receiving data. Full duplex Mode : we can send data in both the directions that is sending and receiving data at same time. Simplex Mode Half duplex Mode Full duplex Mode Network Fundamentals A network is the interconnection of a set of devices capable of communication. In this definition, a device can be a host such as a large computer, desktop, laptop, workstation, cellular phone, or security system. Computer Network Types... PAN (Personal Area Network ). LAN (Local Area Network ). MAN ( Metropolitan Area Network ). CAN ( Campus Area Network ). WAN ( Wide Area Network ). SAN (Storage Area Network ). WLAN ( Wireless Local Area Network ). VPN ( Virtual Private Network ). Network Fundamentals Networks Topologies... Physical topology. Logical topology. ❖ Types of Network Topology. Point-to-Point Topology. Point-to-Multipoint Topology. Bus Network Topology. Ring Network Topology. Dual Ring Network Topology. Star Network Topology. Tree Network Topology. Mesh Network Topology. Hybrid Network Topology. Network Fundamentals Networks Topologies... Topology defines the structure of the network of how all the components are interconnected to each other. There are two types of topology physical and logical topology. Physical topology : describes how network devices (called computers, stations, or nodes) are physically connected in a computer network. Logical topology : represents the data flow from one station to another, how the data is transmitted and received, the path of data in the network, and which protocols are used. Network Fundamentals Networks Topologies... Types of Network Topology : Point-to-Point Network Topology : Point-to-point network topology is the simplest network topology used when only two computers or other network devices are connected to each other. A single piece of cable is used in this case. Network Fundamentals Networks Topologies... Types of Network Topology : Point to Multipoint Topology: is a network structure where a single central node (or device) connects and communicates with multiple endpoints (or devices). Network Fundamentals Networks Topologies... Types of Network Topology : Bus Network Topology : In a bus topology, the main cable is called a common cable or a backbone cable. The stations are connected to this main cable by using other cables that are called drop lines. The tap device is used to connect drop lines to the main cable. Network Fundamentals Networks Topologies... Types of Network Topology : Ring Network Topology: The ring network topology is a modification of the bus topology. In the ring network topology, each station is connected to two other stations on either side. The two other stations are neighbors of this station. Dual Ring Network Topology: The dual ring is a modified version of the ring topology. Network Fundamentals Networks Topologies... Types of Network Topology : Star Network Topology : The star topology is the most common network topology used nowadays for the many advantages it provides. This topology requires a centralized unit, which is called a switch, and all other network devices are connected to this switch with own network cable. A switch has multiple ports. Network Fundamentals Networks Topologies... Types of Network Topology : Tree Network Topology : also known as hierarchical topology or treelike topology, is a type of network topology in which devices are arranged in a hierarchical structure resembling a tree. In a tree topology, a central node (usually a switch or router) acts as the root of the tree, and all other devices (such as computers, printers, and servers) are connected to the root node or to other nodes that are closer to the root. Network Fundamentals Networks Topologies... Types of Network Topology : Mesh Network Topology : A mesh network topology is a configuration in which each station in the network is connected to the other stations. All devices are interconnected with each other. Network Fundamentals Networks Topologies... Types of Network Topology : Hybrid Network Topology : The hybrid topology combines two or more of the network topology types covered earlier. A combination of the star and ring types of network topology is an example of a hybrid network topology. Sometimes you might need the flexibility of two topologies in your network. Network Fundamentals Computer Network Architecture... Computer Network Architecture is defined as the physical and logical design of the software, hardware, protocols, and media of the transmission of data. Simply we can say that how computers are organized and how tasks are allocated to the computer. The two types of network architectures are used : Peer-To-Peer network. Client/Server network. Network Fundamentals Computer Network Architecture... Peer-To-Peer network... A Peer-to-Peer (P2P) network is a type of decentralized computer network in which each participant in the network acts as both a client and a server, allowing each node to share resources and communicate directly with each other without the need for a centralized server. Peer-To-Peer network is useful for small environments, usually up to 10 computers. Peer-To-Peer network has no dedicated server. Network Fundamentals Computer Network Architecture... Advantages Of Peer-To-Peer Network : It is less costly. If one computer stops working but, other computers will not stop working. It is easy to set up and maintain. less specialist knowledge needed. Disadvantages Of Peer-To-Peer Network : No back up data. Less security. Difficult to recover files. Each computer needs its own backup system. Network Fundamentals Computer Network Architecture... Client / Server network... Client-server networks are computer networks that use a dedicated computer (server) to store data, manage / provide resources and control user access. The server acts as a central point on the network upon which the other computers connect to. A computer that connects to the server is called a client. Network Fundamentals Computer Network Architecture... Advantages Of Client / Server network : More secure. One client computer crashing does not effect the other computers. Easy Sharing. easier to administrate the network. Larger networks can be created. Disadvantages Of Client / Server network : Servers can be expensive. A network technician will often be required. Over-all set up cost is more expensive. Server failure will disrupt all computers on the network. Network Fundamentals Networks Devices... Network devices are hardware or software components that are used to facilitate communication and data exchange within a computer network. These devices play a crucial role in establishing and maintaining network connections, ensuring efficient data transfer, and enabling network security. Here are some commonly used network devices: Network Interface Card. Hub. Bridge. Switch. Router. Repeater. Firewalls Network Fundamentals Networks Devices... Network Interface Card (NIC) is installed in your computer to connect, or interface, your computer to the network. A Hub is a device which is used to connect multiple devices in a network. They are generally used to connect computers in a LAN Switches connect multiple segments of a network together much like hubs do, but it use MAC address tables to send data. Switches Hub Network Interface Card (NIC) Network Fundamentals Networks Devices... A router is a device that connects two or more networks or subnetworks. Modems (modulator-demodulator). Modulation: converting from digital to analog. Demodulation: converting from analog to digital. Repeaters are network devices that amplify or regenerate an incoming signal before retransmitting it. A firewall is a network security system that monitors and controls incoming and outgoing traffic based on preset security parameters. Firewall Repeaters Router Network Fundamentals Types of Transmission Media... Transmission media, also known as communication channels, are the physical pathways that carry signals between devices in a communication network. pair