Edison_Corvera,Krystal+Jayne-Assignment+no.1

Network In information technology, a network is a series of points or [|node]s interconnected by communication paths. Networks can interconnect with other networks and contain subnetworks. The most common [|topology] or general configurations of networks include the[|bus], star, [|token ring], and mesh topologies. Networks can also be characterized in terms of spatial distance as local area networks (LANs), metropolitan area networks (MANs), and wide area networks ([|WAN]s). A given network can also be characterized by the type of data transmission technology in use on it (for example, a [|TCP/IP] or [|Systems Network Architecture]network); by whether it carries voice, data, or both kinds of signals; by who can use the network (public or private); by the usual nature of its connections (dial-up or switched, dedicated or nonswitched, or virtual connections); and by the types of physical links (for example, [|optical fiber], [|coaxial cable], and [|Unshielded Twisted Pair]). Large telephone networks and networks using their infrastructure (such as the [|Internet]) have sharing and exchange arrangements with other companies so that larger networks are created. Network Topology Network topology is the layout pattern of interconnections of the various elements ([|links], [|nodes], etc.) of a [|computer network].[|[1]][|[2]] Network topologies may be physical or logical. Physical [|topology] means the physical design of a network including the devices, location and cable installation. [|Logical topology] refers to how data is actually transferred in a network as opposed to its physical design. Topology can be considered as a virtual shape or structure of a network. This shape does not correspond to the actual physical design of the devices on the computer network. The computers on a home network can be arranged in a circle but it does not necessarily mean that it represents a ring topology. Any particular network topology is determined only by the graphical mapping of the configuration of physical and/or logical connections between nodes. The study of network topology uses [|graph theory]. Distances between nodes, physical interconnections, transmission rates, and/or signal types may differ in two networks and yet their topologies may be identical. A [|local area network] (LAN) is one example of a network that exhibits both a physical topology and a logical topology. Any given node in the LAN has one or more links to one or more nodes in the network and the mapping of these links and nodes in a graph results in a geometric shape that may be used to describe the physical topology of the network. Likewise, the mapping of the data flow between the nodes in the network determines the logical topology of the network. The physical and logical topologies may or may not be identical in any particular network.  Types of Network Topologies

Bus Topology: In this type of network topology, all the nodes of a network are connected to a common transmission medium having two endpoints. All the data that travels over the network is transmitted through a common transmission medium known as the bus or the backbone of the network. When the transmission medium has exactly two endpoints, the network topology is known by the name, ‘linear bus topology'. In case the transmission medium, also called as the network backbone, has more than two endpoints, the network is said to have a distributed bus topology. Bus topology is easy to handle and implement and is best suited for small networks. But the downside of this topology is that the limited cable length limits the number of stations, thus limiting the performance to a less number of nodes. Ring Topology: In a ring topology, every node in the network is connected to two other nodes and the first and the last nodes are connected to each other. The data that are transmitted over the network pass through each of the nodes in the ring until they reach the destination node. In a ring network, the data and the signals that pass over the network travel in a single direction. The dual ring topology varies in having two connections between each of the network nodes. The data flow along two directions in the two rings formed thereby. The ring topology does not require a central server to manage connectivity between the nodes and facilitates an orderly network operation. But, the failure of a single station in the network can render the entire network inoperable. Changes and moves in the stations forming the network affect the network operation. Mesh Topology: In a full mesh network, each network node is connected to every other node in the network. Due to this arrangement of nodes, it becomes possible for a simultaneous transmission of signals from one node to several other nodes. In a partially connected mesh network, only some of the network nodes are connected to more than one node. This is beneficial over a fully connected mesh in terms of redundancy caused by the point-to-point links between all the nodes. The nodes of a mesh network require possessing some kind of routing logic so that the signals and the data traveling over the network take the shortest path during each of the transmissions.

Tree Topology ** : ** It is also known as a hierarchical topology and has a central root node that is connected to one or more nodes of a lower hierarchy. In a symmetrical hierarchy, each node in the network has a specific fixed number of nodes connected to those at a lower level.
 * Star Topology:** In this type of network topology, each node of the network is connected to a central node, which is known as a hub. The data that is transmitted between the network nodes passes across the central hub. A distributed star is formed by the interconnection of two or more individual star networks. The centralized nature of a star network provides a certain amount of simplicity while also achieving isolation of each device in the network. However, the disadvantage of a star topology is that the network transmission is largely dependent on the central hub. The failure of the central hub results in total network inoperability.

Apart from these basic types of network topologies, there are hybrid network topologies, which are composed of a combination of two or more basic topologies. These network mappings aim at harnessing the advantages of each of the basic topologies used in them. Network topologies are the physical arrangements of network nodes and wires. What is interesting is that the inanimate nodes and wires turn 'live' for the transmission of information!