Network Topology is the schematic description of a network arrangement, connecting various nodes(sender and receiver) through lines of connection.

#### Topology Names:

• BUS Topology
• RING Topology
• STAR Topology
• MESH Topology
• TREE Topology
• HYBRID Topology
• ### BUS Topology:

Bus topology is a network type in which every computer and network device is connected to single cable. When it has exactly two endpoints, then it is called Linear Bus topology.

#### Features of Bus Topology:

• It transmits data only in one direction.
• Every device is connected to a single cable.
• #### Advantages of Bus Topology:

• It is cost effective.
• Cable required is least compared to other network topology.
• Used in small networks.
• It is easy to understand.
• Easy to expand joining two cables together.
• #### Disadvantages of Bus Topology:

• Cables fails then whole network fails.
• If network traffic is heavy or nodes are more the performance of the network decreases.
• Cable has a limited length.
• It is slower than the ring topology.
• ### RING Topology:

It is called ring topology because it forms a ring as each computer is connected to another computer, with the last one connected to the first.

#### Features of Ring Topology:

• A number of repeaters are used for Ring topology with large number of nodes, because if someone wants to send some data to the last node in the ring topology with 100 nodes, then the data will have to pass through 99 nodes to reach the 100th node. Hence to prevent data loss repeaters are used in the network.
• The transmission is unidirectional, but it can be made bidirectional by having 2 connections between each Network Node, it is called Dual Ring Topology.
• In Dual Ring Topology, two ring networks are formed, and data flow is in opposite direction in them. Also, if one ring fails, the second ring can act as a backup, to keep the network up.
• Data is transferred in a sequential manner that is bit by bit. Data transmitted, has to pass through each node of the network, till the destination node.
• #### Advantages of Ring Topology:

• Transmitting network is not affected by high traffic or by adding more nodes, as only the nodes having tokens can transmit data.
• Cheap to install and expand.
• #### Disadvantages of Ring Topology:

• Troubleshooting is difficult in ring topology.
• Adding or deleting the computers disturbs the network activity.
• Failure of one computer disturbs the whole network.
• ### STAR Topology:

In this type of topology all the computers are connected to a single hub through a cable. This hub is the central node and all others nodes are connected to the central node.

#### Features of Star Topology:

• Every node has its own dedicated connection to the hub.
• Hub acts as a repeater for data flow.
• Can be used with twisted pair, Optical Fiber or coaxial cable.
• #### Advantages of Star Topology:

• Fast performance with few nodes and low network traffic.
• Hub can be upgraded easily.
• Easy to troubleshoot.
• Easy to setup and modify.
• Only that node is affected which has failed, rest of the nodes can work smoothly.
• #### Disadvantages of Star Topology:

• Cost of installation is high.
• Expensive to use.
• If the hub fails then the whole network is stopped because all the nodes depend on the hub.
• Performance is based on the hub that is it depends on its capacity.
• ### MESH Topology:

It is a point-to-point connection to other nodes or devices. All the network nodes are connected to each other. Mesh has n(n-1)/2 physical channels to link n devices.

#### Features of Mesh Topology:

• Fully connected.
• Robust.
• Not flexible.
• #### Advantages of Mesh Topology:

• Each connection can carry its own data load.
• It is robust.
• Fault is diagnosed easily.
• Provides security and privacy.
• #### Disadvantages of Mesh Topology:

• Installation and configuration is difficult.
• Cabling cost is more.
• Bulk wiring is required.
• ### TREE Topology:

It has a root node and all other nodes are connected to it forming a hierarchy. It is also called hierarchical topology. It should at least have three levels to the hierarchy.

#### Features of Tree Topology:

• Ideal if workstations are located in groups.
• Used in Wide Area Network.
• #### Advantages of Tree Topology:

• Extension of bus and star topologies.
• Expansion of nodes is possible and easy.
• Easily managed and maintained.
• Error detection is easily done.
• #### Disadvantages of Tree Topology:

• Heavily cabled.
• Costly.
• If more nodes are added maintenance is difficult.
• Central hub fails, network fails.
• ### HYBRID Topology:

It is two different types of topologies which is a mixture of two or more topologies. For example if in an office in one department ring topology is used and in another star topology is used, connecting these topologies will result in Hybrid Topology (ring topology and star topology).

#### Features of Hybrid Topology:

• It is a combination of two or topologies.
• #### Advantages of Hybrid Topology:

• Reliable as Error detecting and trouble shooting is easy.
• Effective.
• Scalable as size can be increased easily.
• Flexible.
• #### Disadvantages of Hybrid Topology:

• Complex in design.
• Costly.

• ### Basic Concept of Memory Management - CPU, MMU & TLB :

Memory Management is the functionality of an operating system that handles or manages the primary memory and disk during execution. Main memory is also known as RAM.

### Algorithm and Flowchart, Symbols in Flowcharts and Examples of flowcharts :

TCP/IP is an industry-standard protocol suit for Wide Area Networks (WANs) developed in the 1970s and 1980 by the U.S Department of Defense (DoD).

### Basics of Asymmetric Crypto-systems (Encryption, Decryption & Cryptography) :

In networking and telecommunications, it cannot be read by unauthorized users. Cryptography comes from the Greek words "secret writing".

## Computer Science Engineering

Special Notes

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