What is a Network Topology? Network topology is the arrangement of the elements (links, nodes, etc.) of a communication network. Topologies are either physical (the physical layout of devices on a network) or logical (the way that the signals act on the network media, or the way that the data passes through the network from one device to the next)[1]. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial field busses, and computer networks.
Note: To illustrate a concrete example to physical and logical topologies, you can think of them as being wired (there is a physical layout) or being wireless (the signal act on the network media).
While network topologies can be applied into arrays of knowledge domain such as social networks, ontology models, and genomics, our focus herein is only limited (while the core concepts still hold and can be applied into other fields) to telecommunication systems which, in turn, hold significance to our understanding with the Internet — it is also important to note that the concepts we are building in this article are more closely related to the construction of the internet (with small “i”), nonetheless, understanding these concepts will build our foundations to comprehend the complexities of the Internet.
For all intents and purposes, I will leave a few notes to build our intuition with some notable concepts that have lead to the Internet.
1.1. Fundamental Elements of a Graphs: A brief overview of graph theory and network topologies
The abstraction of network topology is graph theory, that is, network topologies applies the notions established in graph theory.
What is graph theory: In discrete mathematics, graph theory is the study of graphs, which are mathematical structures used to model pairwise relations between objects. A graph in this context — does not pertain to a graph of a function (typically projected into some coordinate space) rather is made up of vertices (also called nodes or points) which are connected by **edges **(also called links or lines).
Whereas graph theory has a ton of stuff to offer into molding our basic knowledge of these topologies, our focus [in this article] is to build our understanding with some of the basic structures (topologies) of networks. So, this article will not discuss graph theory, in detail — if ever you are interested and want to build a deeper understanding with these networks I would recommend reading this article https://bit.ly/2yjWM5M.
Suffice to say, that the notion of vertices, edges, undirected (is a graph in which the two endpoints of each edge are not distinguished from each other.) and directed graphs (is one in which the edges have a distinguished direction, from one vertex to another) will help us understand the core concepts behind these topologies — introduced in the succeeding sections.
The very basic building block of the World Wide Web is built upon the concepts introduced here.
1.1.1. Bus topology (linear topology)
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Bus topology is a network type in which every computer and network device is connected to a single cable. It transmits the data from one end to another in a single direction.
Note: No bidirectional feature is in a bus topology, meaning the data transmits only in one direction.
The Big Idea:
A host[2]on a bus network is called a station. In a bus network, every station will receive all network traffic, and the traffic generated by each station has equal transmission priority. A bus network forms a single** network segment**[3] and a collision domain[4]. In order for nodes to share the bus, they use a media access control technology such as carrier sense multiple access (CSMA) or a bus master.
Advantages
● It is easy to connect a computer or device and typically it requires less cable than a star topology.
○ Very easy to connect a computer or peripheral to a linear bus.
○ Requires less cable length than a star topology resulting in lower costs
○ The linear architecture is very simple and reliable
○ It works well for small networks
○ It is easy to extend by joining cable with connector or repeater
○ If one node fails, it will not affect the whole network
Disadvantages
● The entire network shuts down if there is a break in the main wire and it can be difficult to identify the problem if the network shuts down.
○ The entire network shuts down if there is a break in the main cable or one of the T-connectors break
○ A large number of packet collisions on the network, which results in high amounts of packet loss
○ This topology is slow with many nodes in the network
○ It is difficult to isolate any faults on the Network
#networking #discrete-mathematics #computer-science #internet #information-technology
