Lesson Notes By Weeks and Term - Senior Secondary 3

Networking II

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Term: 1st Term

Week: 2

Class: Senior Secondary School 3

Age: 17 years

Duration: 40 minutes of 2 periods each

Date:

Subject:      Computer Studies and ICT

Topic:-       Networks II

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

  1. Discuss the types of networks according to the topology
  2. Draw the flow diagram for each network topology
  3. Outline the advantages and disadvantages of each network topology

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, pictures, Data Processing for senior Secondary Education by Hiit Plc, WAPB Computer Studies for Senior Secondary III by Adekunle et al, On-line Materials.

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION

TEACHER’S ACTIVITY

STUDENT’S ACTIVITY

STEP 1

INTRODUCTION

The teacher reviews the previous lesson on the types of networks according to scale

Students pay attention

STEP 2

EXPLANATION

He discusses the types of networks according to the topology

 

Students pay attention and participates

STEP 3

DEMONSTRATION

He displays a chart showing the flow diagram for each network topology in the class. He further explains the advantages and disadvantages of each network topology

Students pay attention and participate

STEP 4

NOTE TAKING

The teacher writes a summarized note on the board

The students copy the note in their books

 

NOTE

NETWORK TOPOLOGY

Network topology is the arrangement of the various elements (links, nodes, etc.) of a computer network. Network topology refers to the physical or logical layout of a network.

Types of Topology

  1. Bus Topology
  2. Star Topology
  3. Ring Topology
  4. Mesh Topology
  5. Tree Topology
  6. Hybrid Topology

 

BUS TOPOLOGY

All the nodes (file server, workstations, and peripherals) on a bus topology are connected by one single cable. A bus topology consists of a main run of cable with a terminator at each end. All nodes (file server, workstations, and peripherals) are connected to the linear cable. It is popular on LANs because they are inexpensive and easy to install.

 

Advantages of Bus Topology

  1. It is Cheap, easy to handle and implement.
  2. Require less cable
  3. It is best suited for small networks.

 

Disadvantages of Bus Topology

  1. The cable length is limited. This limits the number of stations that can be connected.
  2. This network topology can perform well only for a limited number of nodes.

 

Ring Topology

In a ring network, every device has exactly two neighbours for communication purposes. All messages travel through a ring in the same direction. A failure in any cable or device breaks the loop and can take down the entire network. To implement a ring network we use the Token Ring technology. A token, or small data packet, is continuously passed around the network. When a device needs to transmit, it reserves the token for the next trip around, and then attaches its data packet to it.

 

Advantage of Ring Topology

  1. Very orderly network where every device has access to the token and the opportunity to transmit.
  2. Easier to Mange than a Bus Network
  3. Good Communication over long distances
  4. Handles high volume of traffic

 

Disadvantages of Ring Topology

  1. The failure of a single node of the network can cause the entire network to fail.
  2. The movement or changes made to network nodes affects the performance of the entire network.

 

Star Topology

 

In a star network, each node (file server, workstations, and peripherals) is connected to a central device called a hub. The hub takes a signal that comes from any node and passes it along to all the other nodes in the network. Data on a star network passes through the hub, switch, or concentrator before continuing to its destination. The hub, switch, or concentrator manages and controls all functions of the network. The star topology reduces the chance of network failure by connecting all of the systems to a central node.

 

Advantages of Star Topology

  1. Easy to manage
  2. Easy to locate problems (cable/workstations)
  3. Easier to expand than a bus or ring topology.
  4. Easy to install and wire.
  5. Easy to detect faults and to remove parts.

 

Disadvantages of Star Topology

  1. Requires more cable length than a linear topology.
  2. If the hub or concentrator fails, nodes attached are disabled.
  3. More expensive because of the cost of the concentrators.

Tree Topology

A tree topology (hierarchical topology) can be viewed as a collection of star networks arranged in a hierarchy. This tree has individual peripheral nodes which are required to transmit to and receive from one other only and are not required to act as repeaters or regenerators. The tree topology arranges links and nodes into distinct hierarchies in order to allow greater control and easier troubleshooting

 

Advantages of a Tree Topology

  1. It allows point-to-point wiring for individual segments.
  2. It is supported by several hardware and software vendors.
  3. All the computers have access to the larger and their immediate networks.

 

Disadvantages of a Tree Topology

  1. Overall length of each segment is limited by the type of cabling used.
  2. If the backbone line breaks, the entire segment goes down.
  3. More difficult to configure and wire than other topologies.

 

 

Mesh Topology

 

In this topology, each node is connected to every other node in the network. Implementing the mesh topology is expensive and difficult. In this type of network, each node may send message to destination through multiple paths. While the data is travelling on the Mesh Network it is automatically configured to reach the destination by taking the shortest route which means the least number of hops.

 

Advantage of Mesh Topology

  1. No traffic problem as there are dedicated links.
  2. It has multiple links, so if one route is blocked then other routes can be used for data communication.
  3. Points to point links make fault identification easy.

 

Disadvantage of Mesh Topology

  1. There is mesh of wiring which can be difficult to manage.
  2. Installation is complex as each node is connected to every node.
  3. Cabling cost is high.

 

Hybrid Topology

Hybrid topology is a combination of any two or more network topologies. A hybrid topology always accrues (results) when two different basic network topologies are connected. It is a mixture of above mentioned topologies.

 

Advantages of a Hybrid Topology

  1. It is extremely flexible.
  2. It is very reliable.

 

Disadvantages of a Hybrid Topology

  1. Expensive

 

EVALUATION:    1. Discuss the types of networks according to topology

  1. Draw the flow diagrams for each network topology
  2. Discuss the advantages and disadvantages of each                    network topology

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively