What is Network Topology? Explain the Different Types of Network Topologies. The term physical topology refers to the way in which a network is laid out physically input/output or more devices connect to a link; two or more links form a topology.
Two main types of networking topologies are 1) Physical topology 2) Logical topology Physical topology: This type of network is an actual layout of the computer cables and other network devices. A network topology is defined as the layout or arrangement of elements (usually nodes or links) in a communication network. Network topologies are used to define or describe the arrangement of various types of telecommunication networks â such as computer networks, command and control radio networks, and industrial field busses. What is a network topology? A topology is the layout of how a network communicates with different devices. In this video we discuss the star, bus, ring, mesh. A topology explains how physically the network is designed or what is the structure of the network. These designs are both physical and logical. There are many network topologies 4 like Bus, Star, Ring, and Mesh. But only two types of topologies are used in Ethernet i.e Bus and Star. So, let's know about these two topologies: 1) Bus Topology.
Definition of Network Topology
The term topology in computer networking refers to the way in which a network is laid out physically. Two or more devices connect to a link; two or more links form a topology.
The topology of a network is the geometric representation of the relationship of all links and linking devices (usually called nodes) to one another.
The cost and flexibility of a network installation are partly affected by as is system reliability. Many network topologies are commonly used, but they all have certain similarities.
Information is carried either through space (wireless) or cable. The cable must control the movement of information on the network so that data can be transmitted in a reliable manner.
Network Topology is the schematic description of a network arrangement, connecting various nodes(sender and receiver) through lines of connection.
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There are four basic topologies possible: mesh, star, bus, and ring.
The Different Types of Network Topologies
1. Mesh Topology
In a mesh topology, every device has a dedicated point-to-point link to every other device.
Slideflow 1 0 2 â slideshow on tv wirelessly. The term dedicated means that the link carries traffic only between the two devices it connects.
In a mesh topology, Node1 must be connected to n 1 nodes, node2 must be connected to ( n â 1) nodes, and finally, node n must be connected to (n â 1) nodes. We need n (n â 1) physical links. In other words, we can say that in a mesh topology.
Advantages of Mesh Topology
Disadvantages of Mesh Topology
2. Star Topology
In a star topology, each device has a dedicated point-to-point link only to a central controller, usually called a hub.
Star topology, computers are connected by cable segments to a centralized component, called a hub or switch.
Signals are transmitted from the sending computer through the hub or switch to all computers on the network. This topology originated in the early days of computing with computers connected to a centralized mainframe computer.
It is now a common topology in microcomputer networking.
Doctor 1 8 0 â convert your documents online. Each device has a dedicated point-to-point link only to a central controller, usually called a hub. The devices are not directly linked to one another.
The devices are not directly linked to one another. Unlike a mesh topology, a star topology does not allow direct traffic between devices.
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The controller acts as an exchange: If one device wants to send data to another, it sends the data to the controller, which then relays the data to the other connected device.
Advantages of Star Topology
Disadvantages of Star Topology
3. Bus Topology
The preceding examples all describe point-to-point connections. A bus topology, on the other hand, is multipoint. One long cable acts as a backbone to link all the devices in a network.
The bus topology is also known as a linear bus. In other words, all the nodes (computers and servers) are connected to the single cable (called bus), by the help of interface connectors.
This central cable is the backbone of the network and every workstation communicates with the other device through this bus. It depends on numerous factors including:
Advantages Bus Topology
Disadvantages of Bus Topology
4. Ring Topology
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.
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The ring topology connects computers on a single circle of cable. There are no terminated ends. A ring topology connects one host to the next and the last host to the first.
The signal travels around the loop in one direction and passes through each computer.
Unlike the passive bus topology, each computer acts as a repeater to boost the signal and send it on to the next computer.
Because the signal passes through each computer, the failure of one computer can impact the entire network.
A signal is passed along the ring in one direction, from device to device, until it reaches its destination.
Advantages of Ring Topology
Disadvantages of Ring Topology
5. Hybrid Topology
Before starting about Hybrid topology, we saw that network topology is a connection of various links and nodes, communicating with each other for the transfer of data.
We also saw various advantages and disadvantages of Star, Bus, Ring, Mesh. Hybrid, as the name suggests, is a mixture of two different things.
Similarly in this type of topology, we integrate two or more different topologies to form a resultant topology which has good points (as well as weaknesses) of all the constituent basic topologies rather than having characteristics of one specific topology.
This combination of topologies is done according to the requirements of the organization.
It is two different types of topologies which is a mixture of two or more topologies.
For example, if there is an existing ring topology in one office department while a bus topology in another department, connecting these two will result in Hybrid topology.
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Remember connecting two similar topologies cannot be termed as Hybrid topology. Star-Ring and Star-Bus networks are the most common examples of the hybrid network.
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).
Advantage of Hybrid Topology
The disadvantage of Hybrid Topology
Diagram of different network topologies.
Network topology is the layout of the connections (links, nodes, etc.) of a computer network.[1][2]
There are two main
The names used - such as ring or star - are only rough descriptions. The computers on a home network can be arranged in a circle but it does not necessarily mean that it represents a ring network.
Basic topology types[change | change source]
There are seven basic topologies:[3]
Which of these is chosen depends on what devices need to be connected, how reliable it has to be, and the cost associated with cabling.
Physical topology[change | change source]
The shape of the cabling layout used to link devices is called the physical topology of the network. This refers to how the cables are laid out to connect many computers to one network. The physical topology you choose for your network depends on:
Types of Physical topologies[change | change source]
The mapping of the nodes of the network and the physical connections between them â the layout of wiring, cables, the locations of nodes, and the interconnections between the nodes and the cabling or wiring system.[1]
Types Of Network Topology PptPoint-to-point[change | change source]
The simplest topology is a permanent link between two endpoints (the line in the illustration above). Switched point-to-point topologies are the basic model of conventional telephony. The value of a permanent point-to-point network is the value of guaranteed, or nearly so, communications between the two endpoints. The value of an on-demand point-to-point connection is proportional to the number of potential pairs of subscribers, and has been expressed as Metcalfe's Law.
Bus[change | change source]
Bus network topology
What Is TopologyStar[change | change source]
Star network topology
Ring[change | change source]
Ring network topology
Mesh[change | change source]
Fully connected mesh topology
In most practical networks that are based upon the partially connected mesh topology, all of the data that is transmitted between nodes in the network takes the shortest path between nodes. The network used a longer alternative path in the case of a failure or break in one of the links. This requires that the nodes of the network possess some type of logical 'routing' algorithm to determine the correct path to use at any particular time.
Tree[change | change source]
Tree network topology
Also known as a hierarchy network.
Jixipix artista impresso pro. The type of network topology in which a central 'root' node (the top level of the hierarchy) is connected to one or more other nodes that are one level lower in the hierarchy (i.e., the second level) with a point-to-point link between each of the second level nodes and the top level central 'root' node. Each of the second level nodes that are connected to the top level central 'root' node will also have one or more other nodes that are one level lower in the hierarchy (i.e., the third level) connected to it, also with a point-to-point link, the top level central 'root' node being the only node that has no other node above it in the hierarchy (The hierarchy of the tree is symmetrical.)
Types Of Network Topologies
Each node in the network having a specific fixed number, of nodes connected to it at the next lower level in the hierarchy, the number, being referred to as the 'branching factor' of the hierarchical tree. This tree has individual peripheral nodes.
Logical topology[change | change source]
Logical topology describes the way in which a network transmits information from network/computer to another and not the way the network looks or how it is laid out. The logical layout also describes the different speeds of the cables being used from one network to another.
The logical topology, in contrast to the 'physical', is the wignals act on the network media, or the way that the data passes through the network from one device to the next without regard to the physical interconnection of the devices. A network's logical topology is not necessarily the same as its physical topology. For example, twisted pair Ethernet is a logical bus topology in a physical star topology layout. While IBM's Token Ring is a logical ring topology, it is physically set up in a star topology.
The logical classification of network topologies generally follows the same classifications as those in the physical classifications of network topologies but describes the path that the data takes between nodes being used as opposed to the actual physical connections between nodes.
Notes:
Daisy chains[change | change source]
Except for star-based networks, the easiest way to add more computers into a network is by daisy-chaining, or connecting each computer in series to the next. If a message is intended for a computer partway down the line, each system bounces it along in sequence until it reaches the destination. A daisy-chained network can take two basic forms: linear and ring.
Centralization[change | change source]
The star topology reduces the probability of a network failure by connecting all of the peripheral nodes (computers, etc.) to a central node. When the physical star topology is applied to a logical bus network such as Ethernet, this central node (traditionally a hub) rebroadcasts all transmissions received from any peripheral node to all peripheral nodes on the network, sometimes including the originating node. All peripheral nodes may thus communicate with all others by transmitting to, and receiving from, the central node only. The failure of a transmission line linking any peripheral node to the central node will result in the isolation of that peripheral node from all others, but the remaining peripheral nodes will be unaffected. However, the disadvantage is that the failure of the central node will cause the failure of all of the peripheral nodes also,
If the central node is passive, the originating node must be able to tolerate the reception of an echo of its own transmission, delayed by the two-way round triptransmission time (i.e. to and from the central node) plus any delay generated in the central node. An active star network has an active central node that usually has the means to prevent echo-related problems.
A tree topology (a.k.a. hierarchical topology) can be viewed as a collection of star networks arranged in a hierarchy. This tree has individual peripheral nodes (e.g. leaves) which are required to transmit to and receive from one other node only and are not required to act as repeaters or regenerators. Unlike the star network, the functionality of the central node may be distributed.
As in the conventional star network, individual nodes may thus still be isolated from the network by a single-point failure of a transmission path to the node.If a link connecting a leaf fails, that leaf is isolated; if a connection to a non-leaf node fails, an entire section of the network becomes isolated from the rest.
In order to alleviate the amount of network traffic that comes from broadcasting all signals to all nodes, more advanced central nodes were developed that are able to keep track of the identities of the nodes that are connected to the network. These network switches will 'learn' the layout of the network by 'listening' on each port during normal data transmission, examining the data packets and recording the address/identifier of each connected node and which port it's connected to in a lookup table held in memory. This lookup table then allows future transmissions to be forwarded to the intended destination only.
Decentralization[change | change source]
In a mesh topology (i.e., a partially connected mesh topology), there are at least two nodes with two or more paths between them to provide redundant paths to be used in case the link providing one of the paths fails. This decentralization is often used to advantage to compensate for the single-point-failure disadvantage that is present when using a single device as a central node (e.g., in star and tree networks). A special kind of mesh, limiting the number of hops between two nodes, is a hypercube. The number of arbitrary forks in mesh networks makes them more difficult to design and implement, but their decentralized nature makes them very useful. This is similar in some ways to a grid network, where a linear or ring topology is used to connect systems in multiple directions. A multi-dimensional ring has a toroidal topology, for instance.
A fully connected network, complete topology or full mesh topology is a network topology in which there is a direct link between all pairs of nodes. In a fully connected network with n nodes, there are n(n-1)/2 direct links. Networks designed with this topology are usually very expensive to set up, but provide a high degree of reliability due to the multiple paths for data that are provided by the large number of redundant links between nodes. This topology is mostly seen in military applications. However, it can also be seen in the file sharing protocol BitTorrent in which users connect to other users in the 'swarm' by allowing each user sharing the file to connect to other users also involved. Often in actual usage of BitTorrent any given individual node is rarely connected to every single other node as in a true fully connected network but the protocol does allow for the possibility for any one node to connect to any other node when sharing files.
Network Topology DiagramHybrids[change | change source]
Hybrid networks use a combination of any two or more topologies in such a way that the resulting network does not exhibit one of the standard topologies (e.g., bus, star, ring, etc.). For example, a tree network connected to a tree network is still a tree network, but two star networks connected together exhibit a hybrid network topology. A hybrid topology is always produced when two different basic network topologies are connected. Two common examples for Hybrid network are: star ring network and star bus network
References[change | change source]
Tendaishe Sigauke, (2007: 46) Explaining networking terms
Other websites[change | change source]
Tendaishe Sigauke, (2007: 46) Explaining networking terms
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