COMPUTER NETWORKING

WEEK ONE                           

TOPIC:  NETWORKING

CONTENT:  

• Definition of Networking
• Types of Network
• Network Topology
• Network Devices

Networking is the process of connecting two or more computers or devices together in order to share information and resources. There are several different types of networks, including local area networks (LANs), wide area networks (WANs), intranets, and extranets. Network topology refers to the layout of a network, with some topologies featuring a centralized hub-and-spoke arrangement, while others are more decentralized and rely on peer-to-peer communication. Network devices include routers, switches, firewalls, and network cards. Whether you’re setting up a small home network or a large business network, understanding the key concepts of networking is essential to ensuring that your network functions smoothly.

SUBTOPIC 1:    DEFINITION AND TYPES OF NETWORKING

Network literally means a collection of a large and widely distributed group of people or things such as stores, colleges, or offices that communicate with one another and work together as a unit or system.

A Computer Network, simply referred to as a network, can be defined as a system of two or more computers, terminals and communication devices linked by wires, cables, or telecommunication system in order to exchange data.

The network may be limited to a group of users in a local area (LAN), or it could be global in scope just like the Internet. The major reason network exist is to enable sharing of resources and information among interconnected devices.

TYPES OF NETWORK:

(i)  Ethernet

(ii)  Token Ring

(iii)  Arcnet

Ethernet:

Ethernet is a family of computer networking technologies for Local Area Networks (LANs), it is a protocol that controls the way data is transmitted over a Local Area Network. This network which was commercially introduced in 1980 uses wires (i.e. it is not a wireless technology) in form of either a bus or star topology and supports data transfer rates of about 10Mbps.

An ethernet port (jack or socket) is an opening on computer network equipment that Ethernet cables plug into.

Token Ring:

A Token ring is a type of computer network in which all the computers are arranged in a circle (see diagram below). A token, which is a special bit pattern, travels around the circle. To send a message, a computer catches the token, attaches a message to it, and then allows it continue to travel around the network. It uses a special three-byte frame called a token. Physically, when implemented, the computers are connected through cables to a ‘HUB’, which manages the network in a ring topology manner.A token ring prevents the collision of data when more than one computer in a network attempts to send messages simultaneously. It is the second most popular type of Local Area Network protocol.

Arcnet:

ARCnet (an acronym from Attached Resource Computer Network) is defined as a group of nodes that communicates to one another over a geographically-limited area usually within one building or a campus of buildings. It was developed by John Murphy at Data-point Corporation in the late 1970s.

It was the simplest and least expensive type of Local Area Network, which uses token ring architecture, supported data rates of 2.5Mbps, and connected up to 255 computers. A special advantage of ARCnet is that it permitted various types of transmission media to be mixed on the same network.

EVALUATION

1. Definition Networking
2. State 3 types of Network
3. ARCnet was developed by ______ _____ _______ in the late ________.
4. It was the second most popular type of Local Area Network protocol that uses token ring architecture and supports data rates of 2.5Mbps. Other types include Ethernet and Token Ring.

SUBTOPIC 2:  NETWORK TOPOLOGY

In Computer Networking, topology refers to the layout of connected devices. It is the plan or model in which two or more computing devices are connected in a network.

There are several different types of network topologies, each with their own advantages and disadvantages.

Some common network topologies include:

· Bus Topology: In this type of network, all devices are connected to a central cable called a bus or backbone. Each device acts as an interface point for the data flowing through the bus, and each device can transmit or receive data. This type of network works well for small, simple networks with a limited number of devices. However, it can be prone to issues such as cable breakages and interference from other electrical devices.

BUS TOPOLOGY

Bus network topology uses a common backbone (a cable) to connect all devices. The backbone is a shared communication medium that all devices are attached or connected. A signal from the source travels in both directions to all machines connected on the bus cable until it finds the intended recipient. If the machine address does not match the intended address for the data, the machine ignores the data. Alternatively, if the data matches the machine address, the data is accepted.

An example of bus network is the Ethernet.

Advantages of Bus Topology

• Easy to connect a computer or peripheral
• Inexpensive to implement when compared to other topologies because it requires less cable

Disadvantages of Bus Topology

• Entire network shuts down if there is a break in the main cable
• Terminators are required at both ends of the backbone cable
• Difficult to identify the problem if the entire network shuts down.

· Star Topology: In this type of network, all devices are connected to a central node (such as a hub or switch) using cables. Each device communicates with the central node, which then routes messages to other devices on the network. This type of network is typically less prone to interference and cable breakages than bus topology networks, but it requires more complex hardware and can be more expensive to implement.

STAR TOPOLOGY

Star Network is a local area network in which each device (node) is connected to a central computer in a star-shaped configuration (topology); commonly, a network consisting of a central computer (the hub) surrounded by terminals. The central point may be a hub, a switch or a router, and all the individual network devices communicate with the central point which manages and control all functions of the network. An example of star network topology is the ARCNET.

Advantages of Star Topology

• A star network is reliable in the sense that a node can fail without affecting any other node on the network.
• Easy to install and wire
• Easy to detect faults and remove parts

Disadvantages of Star Topology

• Failure of the central computer results in a shutdown of the entire network.
• If the hub, switch, or concentrator fails, nodes attached are disabled
• Since each node is individually wired to the hub, cabling costs can be high

· Mesh Topology: In this type of network, each device is connected to every other device on the network. This provides a high level of redundancy and ensures that messages are delivered even if some devices or links fail. However, mesh topologies can be difficult to implement and often require expensive, specialized hardware. They may also be slower than other types of networks due to the bandwidth required to transmit data across all the connections.

Choosing the right network topology depends on a number of factors, including the size and complexity of the network, the types of devices being connected, and the requirements for reliability and performance. By understanding the different options and making an informed choice, you can ensure that your organization has a high-quality network that meets its needs.

RING TOPOLOGY

It is a local area network in which devices (nodes) are connected in a closed loop, or ring. Messages in a ring network pass in one direction, from node to node. As a message travels around the ring, each node examines the destination address attached to the message. If the address is the same as the address assigned to the node, the node accepts the message; otherwise, it regenerates the signal and passes the message along to the next node in the circle. Such regeneration allows a ring network to cover larger distances than star and bus networks. It can also be designed to bypass any malfunctioning or failed node.

Advantages of Ring Topology

They can span larger distances than other types

It can also be designed to bypass any malfunctioning or failed node.

Disadvantages of Bus Topology

Failure in one of the network connection results in breakdown of the entire network.

new nodes can be difficult to add.

MESH TOPOLOGY

In Mesh network topology, each computer includes everything it needs to serve as a relay point for sending information to any

NETWORK DEVICES

The network devices are the nodes of the network. They are devices that aid connection and communication.

The common network devices are:

(i)  The Hub

(ii)  The Network Interface card

(iii)  The Switch

(iv)  The Router

(v)  The Modem

The Hub:

A Hub is a device that connects all the other devices in a star network together, thus making them act as a single network segment. Due to the fact that the hub broadcast messages, any message sent by the hub is received by all the devices because the hub is not able to identify the device that owns the message.

Modems:

A Modem, which means Modulator-Demodulator, is a device or program that enables a computer to transmit digitally stored data over telephone or cable lines. A modem converts between analogue and digital waves.

Modem transmit data at different speeds, measured by the number of bits of data they send per second. For example, a 28.8 Kbps modem sends data at 28,800 bits per second. A 56Kbps modem is twice as fast, sending and receiving data at a rate of 56,000 bits per second.

The Switch:

Literally, a switch means a mechanical or electronic device that opens, closes or changes the connections in an electrical circuit. Examples are the ones used to turn light on or machine on or off. In computing, a switch is a programmed technique for indicating which alternative path to take at a decision point in a program’s logic. They are key components of computer networks which could connect multiple PCs, printers, servers, and other hardware.

Unlike the hub, the switch is intelligent because it does not broadcast but channels the data to the specific destination.

Routers:

A Router is a network device that connects networked computers to the internet, allowing multiple users to share a connection. A Router acts as a dispatcher, choosing the best route (passage) for information to travel, so that it is transmitted as efficiently as possible.

Network Interface Card:

A Network Interface Card (referred to as network adapter, LAN adapter or card) is an expansion board inserted into a computer so as to be connected to a network. Networked computers communicate with each other using a given protocol for transmitting data packets between the different machines, known as nodes.

EVALUATION

(i)  Define Network Topology

(ii)  Briefly explain the following network devices (a) Router (b) Hub (c) Switch  (d) Modem (e) Network Interface Card

(i) Network topology is the arrangement of connected devices in a network.

(ii) The common network devices are routers, hubs, switches, modems, and network interface cards. Each of these devices has its own function in the network and helps to facilitate communication and connection between different devices.

(a) A router is a network device that connects networked computers to the internet, allowing multiple users to share a connection. It acts as a dispatcher, choosing the best route for information to travel in order to be transmitted as efficiently as possible.

(b) A hub is a device used in star networks that connects all the other devices in a network together, essentially making them act as a single network segment. It broadcasts messages to all devices connected to the hub, which means that any message sent by the hub is received by all the devices.

(c) A switch is an intelligent network device that functions by directing data packets from one node to another in a network. Unlike the hub, which broadcasts all messages to all devices, the switch channels data packets to only their intended destination, thus improving network performance and efficiency.

(d) A modem is a device or program that enables computers to transmit digitally stored data over telephone or cable lines. It converts between analogue and digital waves by modulating and demodulating signals in order to transmit data at different speeds.

(e) A network interface card is an expansion board that is inserted into a computer to allow the computer to communicate with other devices. It acts as a physical or virtual medium between the computers on a network, allowing them to exchange information and share resources. It is responsible for managing data transfer and ensuring that all network traffic is received and processed correctly.

GENERAL EVALUATION

(i)  Clearly distinguish between Ethernet and ARCnet

(ii)  Differentiate between Star and Bus topology

(iii)  Enumerate FIVE benefits of networking

READING ASSIGNMENT

Log to the internet and carry out a research on ‘The Benefits of Networking’.

(i) Ethernet and ARCnet are two different networking technologies that are commonly used for transmitting data across computer networks.

(ii) In terms of topology, star topology refers to a network structure where all devices in the network are connected to a central hub or switch, whereas bus topology consists of multiple computers connected in a linear

WEEKEND ASSIGNMENT

1. ___can be defined as the act of linking two or more computers through wires, cables, or telecommunication system in order to exchange data.

(a) Networking (b) Sharing (c) Connection (d) Wiring

.2 Which of the following is not a common network device?

(a) Router (b) Hub (c) Switch (d) Modem

3. A ______ is a physical or virtual medium that connects computers on a network and allows them to exchange information.

(a) Network Interface Card (b) Switchboard (c) Networking has a number of benefits that can help businesses improve efficiency and productivity.

4. ___ is a protocol that controls the way data is transmitted over a Local Area Network.

(a) Ethernet (b)  Token ring (c)ARCnet (d)  Internet

5. ___ARCnet is an acronym for

6. Which of the following is NOT a network device?

(a)  Hubs (b) Modems (c) Router(d)Protocols

7. ___refers to the physical layout of connected devices

(a)  Arrangement (b) Configuration (c) Topology (d) Networking

8. Relating the information from your research, write a 1-2 page essay elaborating on the benefits of networking and its importance in modern society.

THEORY

1.    Draw a ring network structure

2.    Clearly distinguish between Physical Topology and Logical topology

3. Outline the different types of Network Topologies