TOPOLOGY
Definition:
The term physical topology refers to the way in which a network is laid out physically. It refers to the configuration of cables, computers, and other peripherals. The topology of a network is the geometric representation of the relationship of all the links and linking devices (usually called nodes) to one another.
There are six types of topologies:
i. Mesh topology.
ii. Star topology.
iii. Ring topology.
iv. Tree topology.
v. Bus topology.
vi. Hybrid topology.
Mesh Topology:
In a mesh topology, every device has a dedicated point-to-point link to every other device. The term dedicated means that the link carries traffic only between the two devices it connects. Here, if we have n nodes, then we need to connect to n-1 nodes and n(n-1) physical links. However, if each physical link allows communication in both directions (duplex mode), we need n(n-1)/2 links.
Advantages of a Mesh Topology
Disadvantages of a Mesh Topology
Star Topology:
In local area networks where the star topology is used, each machine is connected to a central hub. The star topology allows each machine on the network to have a point to point connection to the central hub. All of the traffic which transverses the network passes through the central hub. The hub acts as a signal booster or repeater which in turn allows the signal to travel greater distances.
Advantages of a Star Topology
Disadvantages of a Star Topology
Ring Topology:
In local area networks where the ring topology is used, each computer is connected to the network in a closed loop or ring. The signal passes through each machine or computer connected to the ring in one direction, from device to device, until it reaches its destination. Each machines or computers connected to the ring act as signal boosters or repeaters. When a device receives a signal intended for another device, its repeater regenerates the bits and passes them along.
Advantages of a Ring Topology
· It is relatively easy to install and reconfigure.
Disadvantages of a Ring Topology
· Only one machine can transmit on the network at a time.
· The failure of one machine will cause the entire network to fail.
Tree Topology:
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, while 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
Advantages of a Tree Topology
Disadvantages of a Tree Topology
Bus Topology:
In local area networks where bus technology is used, each machine is connected to a long, single cable. The cable acts as a backbone to link all the devices in a network. Each computer or server is connected to the single bus cable through drop lines and some kind of connector. A terminator is required at each end of the bus cable to prevent the signal from bouncing back and forth on the bus cable.
Advantages of Bus Topology
Disadvantages of Bus Topology
Hybrid Topology:
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.). A hybrid topology is always produced when two different basic network topologies are connected.
Advantages of a Hybrid Topology
· It provides a better result by it.
· It can be designed in many ways for various purposes.
Disadvantages of Hybrid Topology
· It is costly.
References:
· Data Communication and Networking By Behrouz A Forouzan.
· Wikipedia and other websites.
Created By- A.H.M Tasbir Farid,
B.Sc in Telecommunication & Electronic Engineering, Hajee Md. Danesh Science & Technology University, Dinajpur, Bangladesh.
he most commonly used network topology is a hybrid topology called the Star Bus Topology
in bus topology computers are connected with each other by a wire in a approximately strait manner..and if one computer stops working the whole network will stop. while in star topology every computer is connected with the host computer & much wire is require..and if any client computer tops working it will not effect the whole network.----ravi singh chauhan...7275974787
Can a single physical topology support multiple logical topologies give a proper reason.
The main communication or network protocol is the TCP/IP protocol. (Transmission Control Protocol/Internet Protocol)
Star Topology, where Hubs can act as repeaters.
The advantages of ring network are:
A Bus
Source: Page 195 Network+ Guide to Networks 5e
ALL types of networks LAN/WAN/MAN and SAN.... this is simply a preference as tp how you would like it to be set up.
the inventor of star topology is Sean Ross Remigio that connect the pc to stars.
generally its used for fail-over and reliability. obviously the more connections you have the more reliable your connection however you also have to be aware that the more connections you have on multi-point you also have more security risks involved versus point-to-point connections in which there is only one port to watch and secure which will lower your total surface of attack area.
The internet uses a very complex topology, due to the massive number of nodes and the high redundancy that is characteristic of high availability systems like the internet. Different parts of the internet look like different topologies. The internet would be best approximated as a mesh topology.
For an image of a simple mesh topology, and a discussion of the different possible network topologies, see the wikipedia article in the links below.
the advantage of information points:
the disadvantage of information points:
A star topology is a method of connecting several computers to one another in a network. The cables used in a star topology are twisted pair cables or coaxial cables. Coaxial cables would be the cheapest solution.
The minimum needed to make the mesh. "Mesh" could refer to several types of groups of computers. There is grid computing, where a large number of small computers all work in parallel. Modern supercomputers, like those used by physicists and weather forecasters (seriously), use grids. Another is distributed computing. Nearly identical in description, the difference is in parlance. Grid may refer to large numbers of computers at one company under control of a dedicated group, where distributed computers usually means dispersed computers. An example might be many computer systems at top research universities working on the same problem. Another is cloud computing. Clouds are groups of computers not necessarily working together on something. The Internet is one example. Seti@Home is famous for harnessing the individual power of millions of (simple, low-power) computers throughout the Internet cloud to create an ultrapowerful distributed grid. You no longer need to create your own supergrid software. You can hire a company like grid.org to solve your problem. For example, analyzing chemicals to see if they'd have any effect on cancerous cells.
Sure, the machines have to be connected somehow. A star topology is quite common.
Considerations for selecting a topologySelecting an appropriate topology for your deployment environment depends upon several factors.
When you select a topology pattern, consider the following factors:
15 usually but it can change over time