Introduction to Computer Networks Exercise 1 Objectives Statement

Introduction to Computer Networks Exercise # 1 Objectives / Statement Purpose: To study about some basic concepts of Computer Networks Describe the Network Devices Explain how devices use in the internetwork Types of Network Internet in detail Activity Outcomes: The student should know the Infrastructure of Internet The students should know how networks helping us in daily life The student should know the network devices in detail with their applications Instructions: The purpose of the networking guidelines are as follows: To assist students in understanding the benefits of networking. . To assist students in planning the next stage of network development To provide standard networking ‘models’ and best practice to students that will assist students in their network planning.

A network is a set of devices (often referred to as nodes) connected by communication links. A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network. Distribued Procession Network Criteria Physical Structures Network Models Interconnection of Networks: Internetwork 1 - Distributed Processing: - A task is divided among multiple computers. 2 - Network Criteria: A network must be able to meet a certain number of criteria. The most important of these are performance, reliability and security.

Interconnection of Networks: Internetwork Distributed Processing: - A task is divided among multiple computers. Network Criteria: A network must be able to meet a certain number of criteria. The most important of these are performance, reliability and security. 1. Performance: - Performance is measured in many ways including transit time and response time. Transit time is the amount of time required for a message to travel from one device to another. Response time is the elapsed time between an query and a response ii. Reliability: - Reliability is measured by the frequency of failure, the time it takes a link to recover from a failure. iii. Security: - Network security issues include protecting data from unauthorized access.

. Physical Structures Types of connections: A network is two or more devices connected through links. A link is a communications pathway that transfers data from one device to another a) Point- to-point: - A point to point connection provides a dedicated link between two device. b) Multipoint: -A multipoint connection is one in which more than two specific devices share a single link.

Physical topology: - the term physical topology refers to the way in which a network is laid out physically Mesh: - In a mesh topology every device has a dedicated point-topoint link to every other device Star topology: -In a star topology each device has a dedicated point -to-point link only to a central controller, usually called a hub. Bus topology: - A bus topology, on the other hand, is multipoint. One long cable acts as a backbone to link all the devices in a network. Ring topology: -In a ring topology, each device has a dedicated point-to-point connection with only the two devices on either side of it. A signal is passed along the ring in one direction, from devices to device, until it reaches its destination. Hybrid topology: - A network can be hybrid. For example, we can have a main star topology with each branch connecting several stations in a bus topology.

Categories of topology

A fully connected mesh topology (five devices)

A star topology connecting four stations

A bus topology connecting three stations

A ring topology connecting six stations

A hybrid topology: a star backbone with three bus networks

4. Network Models: - Standards are needed so that these heterogeneous networks can communicate with one another. The two best known standards are the OSI model and the internet model. 5. Categories of networks • LAN (local Area Network) is usually privately owned and links the devices in a single office, building or campus. • WAN (Wide area Network) provides long-distance transmission of data, image, audio and video information over large geographic areas that may comprise a country a, a continent or even the whole world. • MAN (Metropolitan Area Network) is a network with the size between a Lan and a WAN. It normally covers the area inside a town or a city.

6. Interconnection of Networks: Internetwork: -When two or more networks are connected, they become an internetwork or internet. An isolated LAN connecting 12 computers to a hub in a closet