Computer Networks: Data Communication, Models, and Security, Slides of Computer Networks

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COMPUTER NETWROEK

NOTE: All topics are written here except “Routing Algorithm”

SOORAJ KUMAR

ROLL# DEPARTMENT SUBJECT ASSIGNED BY 2K17/CSEE/ Computer Science (Evening) Computer Network Dr. Ayaz Keerio [email protected]

Dad Road Daharki, district Ghotki, Sindh

DATA COMMUNICATION

❑ Data Communication ❑ Communication Model ❑ Origin of Internet Chapter 01

DATA COMMUNICATION Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable.

COMMUNICATION MODEL Workstation Modem (^) Public Telephone Network Modem Server Source (^) Transmitter Transmission System Receiver Destination

Origins of Internet The Internet evolved from the ARPANET, which was developed in 1969 by the Advanced Research Project Agency of the U.S. Department of Defense. It was the first operational packet switching networks. ARPANET began operations in four locations. Today the no. of hosts is in the hundreds of millions, the number of users in the billions, and number of countries participating nearly 200.

COMPUTER NETWORK A computer network is a set of connected computers. Computers on a network are called nodes. The connection between computers can be done via cabling, most commonly the Ethernet cable, or wirelessly through radio waves. Connected computers can share resources, like access to the Internet, printers, file servers, and others NETWORK DIAGRAM Two main types of Computer Network 1: Local Area Network (LAN) 2: Wide Area Network (WAN)

LOCAL AREA NETWORK (LAN) A local area network (LAN) is a collection of devices connected to gather in one physical location, such as a building, office, or home. Regardless of size, a LAN's single defining characteristic is that it connects devices that are in a single, limited area. Local Area Network (LAN) Topology 1: Bus Topology 2: Ring Topology 3: Star Topology 4: Tree Topology 5: Mesh Topology

NETWORK TOPOLOGIES ❑ Topology is the physical and logical arrangement of a network. ❑ The physical arrangement of the network refers to how the workstations, servers, and other equipment are joined to gather with cables and connectors. ❑ The way or path data flows through the network is called logical topology.

BUS TOPOLOGY Advantages Disadvantages It is used for small network. you don’t need to manage a complex topological setup. Bus topology is also low cost to install it. Bus topologies have a single point of failure. If the cable fails, then the entire network will go down. high network traffic would decrease network performance Every device is connected to a single cable that runs from one end of the network to the other. It is also called Line Topology. Data is transmitted in one direction only.

RING TOPOLOGY Advantages Disadvantages The risk of packet collision is very low. In this time to send data is known. It is easy to install and fault identification is easy. The failure of one node can take the entire system down. Making changes is very difficult because you need to shut down the network. It is expensive and requires more cables. Computers are connected each other in a circular format. Every device in the network will have two neighbors. The first node is connected to the last node to link the loop together.

TREE TOPOLOGY Advantages Disadvantages Tree topologies are used to extend bus and star topologies. It is easy to add more nodes to the network. Error detection and correction is easy. Damaged nodes are not affected to others. If the root node fails, then all its subtrees become partitioned. Maintaining the network system is not simple either because the more nodes you add, the more difficult it becomes to manage the network. Tree topology has a root node and all other nodes are connected to it forming hierarchy. It is also called hierarchical topology. It should at least have tree levels to the hierarchy.

COMPUTER NETWORK

Model

❑ Computer Network Model ❑ TCP/IP Model ❑ OSI Model Chapter 03

CN Model TCP/IP Model OSI Model A network model reflects a design or architecture to accomplish communication between different systems. A network model usually consists of layers. Each layer of a model represents specific functionality. Within the layers of a model, there are usually protocols specified to implement specific tasks. You may think of a protocol as a set of rules or a language. Thus, a layer is normally a collection of protocols.