By: Hafsa Noor (roll number: 1111-BH-GEOG-2018)

NETWORK TOPOLOGIES

(Uses and types of topologies)

INDEX

1. Topology Physical topology Logical topology

2. Bus topology Distributed bus topology Linear bus topology

3. Mesh topology Fully mesh Partially mesh

4. Tree topology5. Ring topology

Unidirectional ring topology Bidirectional ring topology

6. Star topology Extended star Distributed star

7. Hybrid topology8. Point-to-point topology

Permanent point-to-point Switched point-to-point

9. Uses of network topologies 1)

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TOPOLOGY

Two different definitions of topology are as follows: physical and logical.

The physical topology of a network is the layout or actual appearance of the cabling scheme used on a network.

The logical topology of a network describes how the data flows through the physical topology.

Physical TopologiesAll physical topologies are variations of two fundamental methods of connecting devices: point-to-point and multipoint.

The following four types of physical topologies are frequently used in computer networking:

1. Star2. Bus3. Ring4. Hybrid

And also these topologies are divided into sub topologies, there are some other topologies also which are included in Logical topologies.

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BUS TOPOLOGY

Definition:Bus topology is a specific kind of network topology in which all of the various devices in the network are connected to a single cable or line. In general, the term refers to how various devices are set up in a network.A signal from the source is broadcasted and it travels to all workstations connected to bus cable. A terminator is added at ends of the central cable, to prevent bouncing of signals. A barrel connector can be used to extend it.

Figure:

Figure 1 BUS TOPOLOGY

Types of bus topology:There are two main types of bus topology:

1. Distributed bus topology2. Linear bus topology

o Distributed bus:In a distributed bus topology, there may be more than one linear pattern connected to the network.The type of network topology in which all of the nodes of the network are connected to a common transmission medium which has more than two endpoints that are created by adding branches to the main section of the transmission medium is known as distributed bus topology.

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o Linear bus topology:

Linear bus topology is a type of network topology in which each devices connected one after the other in a sequential chain. A linear bus topology implies that there is just one line associated with two distinct endpoints.

Advantages of bus topology: Bus topologies are often valued for their

simplicity and lower cost of implementation.

For a small network, bus topology works well. Installation of Bus topology is very easy as compared to other

topologies. Cable length required for this topology is the least compared to other

networks.

Disadvantages of bus topology: If the central line is compromised, the entire network will go down. It can be difficult to troubleshoot these kinds of systems, and problems

like data signal loss can occur with a longer linear cable. Its security is very low because all the computers receive the sent signal

from the source. Bus topology is not well workable for larger networks, Terminators are

required for both ends of the main cable.

MESH TOPOLOGY

DEFINITION:A network setup where each computer and network device is interconnected with one another, allowing for most transmissions to be distributed even if one of the connections go down is called mesh topology. Routers are used to provide the best and most efficient data path for effective communication. In the event of a hardware failure, many routes are available to continue the network communication process.

Figure:

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Figure 2 LINEAR BUS TOPOLOGYhttps://www.computerhope.com/jargon/l/linear-bus-

topology.htm

Figure 3 MESH TOPOLOGY

Types of Mesh topology:There are two main types of mesh topologies:

1. Fully connected network2. Partially connected network

o Fully mesh topology:In a full mesh topology, every computer in the network has a connection to each of the other computers in that network. This provides greater redundancy, because if any node fails, the network traffic can be directed using other nodes.

o Partial mesh topology: In a partially connected mesh topology, at least two of the computers in the network have connections to multiple other computers in that network. It is an inexpensive way to implement redundancy in a network.

Advantages of mesh topology: If a break occurs in a segment of cable, traffic can still be rerouted using

the other cables. This topology is rarely used because of the significant cost and work

involved in having network components directly connected to every other component.

A mesh topology provides redundant links across the network.

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Figure 4 FULLY MESH TOPOLOGYhttps://www.sciencedirect.com/topics/computer-

science/mesh-topology

Disadvantages of mesh topology: The chance of redundant connection is high, which adds to the high

cost and potential to reduced efficiency. The installation and maintenance of mesh topology is difficult. It is quite expensive as compared to other topologies.

TREE TOPOLOGY

Definition:A tree topology is a special type of structure in which many connected elements are arranged like the branches of a tree. Tree topologies are frequently used to organize the computers in a corporate network, or the information in a database.Experts may define a tree topology as a combination of star and bus topologies, where multiple elements are connected through a single lateral connection.

Figure:

Figure 5 TREE TOPOLOGY https://fcit.usf.edu/network/chap5/chap5.htm

Advantages of tree topology: A Tree topology is a good choice for large computer networks as the tree

topology "divides" the whole network into parts that are more easily manageable.

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Detection and correction of faults is easy because each device is connected to a central device through a dedicated link.

Easy to expend and implementation the network. If one device is damaged then the other devices are not affected.

Disadvantages of tree topology: If there is a problem with the main cable, the entire network goes

down. This network is not secure, anyone can see transmitted data. The maintenance becomes difficult as more and more nodes and

segments are added

RING TOPOLOGY

Definition: The topology in which all of the nodes are connected in a closed loop and messages travel around the ring, with each node reading those messages addressed to it. This type of topology is called ring topology.Ring topology refers to a specific kind of network setup in which devices are connected in a ring and pass information to or from each other according to their adjacent proximity in the ring structure.

Figure:

Figure 6 RING TOPOLOGY http://slogcsc104.blogspot.com/2012/11/networks.html

Types of ring topology:There are two types of the Ring Topology based on the data flow:

1. Unidirectional ring topology2. Bidirectional ring topology

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o Unidirectional ring:Most ring topologies allow packets to travel only in one direction, called a unidirectional ring network.

o Bidirectional ring:Most ring topologies permit data to move in either direction, called bidirectional.

Advantages of ring topology: it can span larger distances than other types of networks because each

node regenerates messages as they pass through it. It has ability to handle heavy network communications better than some

other setups. Installation and troubleshooting are also relatively easy with this kind of

network. Installation and troubleshooting are also relatively easy with this kind of

network. Reduced chances of data collision as each node release a data packet

after receiving the token.

Disadvantages of ring topology: Just one failure to transmit data can impact the entire network. The hardware needed to connect each workstation to the network is

more expensive than Ethernet cards and hubs/switches. Moving, adding and changing the devices can affect the network. In ring topology, the maximum ring length and numbers of nodes are

limited.

STAR TOPOLOGYDefinition:In a star network devices are connected to a central computer, called a hub. Nodes communicate across the network by passing data through the hub.Figure:

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Figure 7 STAR TOPOLOGY https://fcit.usf.edu/network/chap5/chap5.htm

Types of star topology:There are two types of star topology:

1. Extended star 2. Distributed star

o Extended star:The extended star network topology extend a physical star topology by one or more repeaters between the central node and the peripheral (spoke) nodes.

o Distributed star:A type of network topology that is composed of individual networks that are based upon the physical star topology connected in a linear fashion is known as distributed star topology.

Advantages of star topology: In a star network, one malfunctioning node doesn't affect the rest of the

network. Easy to install and wire. No disruptions to the network when connecting or removing devices. Easy to detect faults and to remove parts.

Disadvantages of star topology:

It requires more cable length than a linear topology. If the hub, switch, or concentrator fails, nodes attached are disabled. It is more expensive than linear bus topologies because of the cost of the

hubs, etc.

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HYBRID TOPOLOGY

Definition:Hybrid topology uses two or more different network topologies. These topologies include a mix of bus topology, mesh topology, ring topology, star topology, and tree topology.

Figure:

Figure 8 HYBRID TOPOLOGY

https://www.slideshare.net/siddiqueibrahim37/network-topologyppt

Advantages: It is very reliable and easy to detect the Faulty system. Troubleshooting from hybrid topology is easy. It includes both wired and wireless network. It is an expandable network.

Disadvantages of hybrid topology: Its design is difficult to understand. The cost of this network design is high, because of the requirement

of a lot of cables, cooling systems, etc. For hybrid topology, MAU ( Multi-station Access Unit) is required.

POINT-TO-POINT TOPOLOGY

Definition:Point To point (PTP) topology connects two nodes directly together. n this topology, two same ports of devices are connected directly to each other.

The following EXAMPLES are pure point to point links:

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•Two computers communicating via modems.•A mainframe terminal communicating with a front end processor.•A workstation communicating along a parallel cable to a printer.

Figure:

Figure 9 POINT-TO-POINT TOPOLOGY

http://academy.delmar.edu/Courses/ITNW2313/3Topology.html

Types:There are two types of point-to-point topology:

1. Permanent point-to-point2. Switched point-to-point

Advantages: Highest Bandwidth Low Latency Very simple connectivity Easy to handle Replace it in few seconds Genuinely

Disadvantages:There are no bad points for this topology except Link fails due to port fails.

DAISY CHAIN TOPOLOGYDefinition:Daisy chain is the other most adopted topology in traditional industrial automation networks. Cable segments interconnect multiple devices, being the devices part of the network cable.

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Figure:

Figure 10 DAISY CHAIN TOPOLOGY https://www.tutorialspoint.com/data_communication_computer_network/computer_network_topologies.htm

Types: There are two types of daisy chain topology:

1. Ethernet daisy chain2. Deploying daisy chain

Disadvantages of daisy chain topology: Dual port Ethernet devices only support 10 Mbit/s and/or 100 Mbit/s

operational speeds and must use one or the other. The network will operate only as fast as the slowest device that is

connected to the network.

USES OF NETWORK TOPOLOGIES

1. Network topologies plays a significant role in the functioning of networks.

2. Network topologies Helps us better understand the networking concepts.

3. Network topologies Plays a crucial role in performance.4. These topologies Helps reduce the operational and maintenance costs

such as cabling costs.5. A network topology is a factor in determining the media type to be used

to cable a network.6. Error or fault detection is made easy using network topologies.7. Effective utilization of resources and networking components.

REFERENCES

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https://www.sciencedirect.com/topics/computer-science/mesh- topology

https://www.computerhope.com/jargon/m/mesh.htm https://www.orosk.com/tree-topology/ https://fcit.usf.edu/network/chap5/chap5.htm https://www.computerhope.com/jargon/r/ringtopo.htm http://slogcsc104.blogspot.com/2012/11/networks.html https://pctechnicalpro.blogspot.com/search?q=star+topology https://studylib.net/doc/9428722/point-to-point-topology http://academy.delmar.edu/Courses/ITNW2313/3Topology.html https://www.tutorialspoint.com/

data_communication_computer_network/computer_network_topologies.htm

http://techgenix.com/network-topology/

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