Internet topology

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Internet topology is the network topology of the Internet.

Network topology arrangement of the various elements of a computer network; topological structure of a network and may be depicted physically or logically

Network topology is the arrangement of the elements of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial fieldbusses, and computer networks.

Internet Global system of connected computer networks

The Internet is the global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide. It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and file sharing. Some publications no longer capitalize "internet".

Contents

The Jellyfish and Bow Tie models are two attempts at modeling the topology of hyperlinks between web pages. [1] [2]

Models of web page topology

Jellyfish Model

The simplistic Jellyfish model of the Internet centers around a large strongly connected core of high-degree web pages that form a clique; pages such that there is a path from any page within the core to any other page. In other words, starting from any node within the core, it is possible to visit any other node in the core just by clicking hyperlinks. From there, a distinction is made between pages of single degree and those of higher order degree. Pages with many links form rings around the center, with all such pages that are a single link away from the core making up the first ring, all such pages that are two links away from the core making up the second ring, and so on. Then from each ring, pages of single degree are depicted as hanging downward, with a page linked by the core hanging from the center, for example. In this manner, the rings form a sort of dome away from the center that is reminiscent of a jellyfish, with the hanging nodes making up the creature's tentacles.

Strongly connected component subgraph of a directed graph containing paths in both directions between each pair of vertices

In the mathematical theory of directed graphs, a graph is said to be strongly connected or diconnected if every vertex is reachable from every other vertex. The strongly connected components or diconnected components of an arbitrary directed graph form a partition into subgraphs that are themselves strongly connected. It is possible to test the strong connectivity of a graph, or to find its strongly connected components, in linear time.

Degree (graph theory) number of edges incident to a given vertex in a node-link graph

In graph theory, the degree of a vertex of a graph is the number of edges incident to the vertex, and in a multigraph, loops are counted twice. The degree of a vertex is denoted or . The maximum degree of a graph G, denoted by Δ(G), and the minimum degree of a graph, denoted by δ(G), are the maximum and minimum degree of its vertices. In the multigraph on the right, the maximum degree is 5 and the minimum degree is 0. In a regular graph, all degrees are the same, and so we can speak of the degree of the graph. A complete graph is a special kind of regular graph where all vertices,p ,have the maximum degree, p-1. A complete graph is denoted with the form Kp where p is the number of vertices in the graph.

Clique (graph theory) subset of the vertices of a node-link graph that are all adjacent to each other

In the mathematical area of graph theory, a clique is a subset of vertices of an undirected graph such that every two distinct vertices in the clique are adjacent; that is, its induced subgraph is complete. Cliques are one of the basic concepts of graph theory and are used in many other mathematical problems and constructions on graphs. Cliques have also been studied in computer science: the task of finding whether there is a clique of a given size in a graph is NP-complete, but despite this hardness result, many algorithms for finding cliques have been studied.

Bow Tie Model

The Bow Tie model comprises four main groups of web pages, plus some smaller ones. Like the Jellyfish model there is a strongly connected core. There are then two other large groups, roughly of equal size. One consists of all pages that link to the strongly connected core, but which have no links from the core back out to them. This is the "Origination" or "In" group, as it contains links that lead into the core and originate outside it. The counterpart to this is the group of all pages that the strongly connected core links to, but which have no links back into the core. This is the "Termination" or "Out" group, as it contains links that lead out of the core and terminate outside it. A fourth group is all the disconnected pages, which neither link to the core nor are linked from it. [3] [4]

The Bow Tie model has additional, smaller groups of web pages. Both the "In" and "Out" groups have smaller "Tendrils" leading to and from them. These consist of pages that link to and from the "In" and "Out" group but are not part of either to begin with, in essence the "Origination" and "Termination" groups of the larger "In" and "Out". This can be carried on ad nauseam, adding tendrils to the tendrils, and so on. Additionally, there is another important group known as "Tubes". This group consists of pages accessible from "In" and which link to "Out", but which are not part of the large core. Visually, they form alternative routes from "In" to "Out", like tubes bending around the central strongly connected component. [3] [4]

See also

Related Research Articles

Routing is the process of selecting a path for traffic in a network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone network (PSTN), and computer networks, such as the Internet.

World Wide Web System of interlinked hypertext documents accessed over the Internet

The World Wide Web (WWW), commonly known as the Web, is an information space where documents and other web resources are identified by Uniform Resource Locators, which may be interlinked by hypertext, and are accessible over the Internet. The resources of the WWW may be accessed by users by a software application called a web browser.

Hyperlink computing term; reference to data that the reader can directly follow either by clicking, tapping, or hovering

In computing, a hyperlink, or simply a link, is a reference to data that the reader can directly follow either by clicking or tapping. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks. The text that is linked from is called anchor text. A software system that is used for viewing and creating hypertext is a hypertext system, and to create a hyperlink is to hyperlink. A user following hyperlinks is said to navigate or browse the hypertext.

Scalable Coherent Interface organization

The Scalable Coherent Interface or Scalable Coherent Interconnect (SCI), was a high-speed interconnect standard for shared memory multiprocessing and message passing used in the 1990s. The goal was to scale well, provide system-wide memory coherence and a simple interface; i.e. a standard to replace buses in multiprocessor systems without the inherent scalability and performance limitations of buses. The IEEE Std 1596-1992, IEEE Standard for Scalable Coherent Interface (SCI) was approved by the IEEE standards board on March 19, 1992.

Scale-free network network whose degree distribution follows a power law

A scale-free network is a network whose degree distribution follows a power law, at least asymptotically. That is, the fraction P(k) of nodes in the network having k connections to other nodes goes for large values of k as

Web mining is the application of data mining techniques to discover patterns from the World Wide Web. As the name proposes, this is information gathered by mining the web. It makes utilization of automated apparatuses to reveal and extricate data from servers and web2 reports, and it permits organizations to get to both organized and unstructured information from browser activities, server logs, website and link structure, page content and different sources.

Ring network network topology

A ring network is a network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node - a ring. Data travels from node to node, with each node along the way handling every packet.

Backbone network part of a network that connects other networks together

A backbone is a part of computer network that interconnects various pieces of network, providing a path for the exchange of information between different LANs or subnetworks. A backbone can tie together diverse networks in the same building, in different buildings in a campus environment, or over wide areas. Normally, the backbone's capacity is greater than the networks connected to it.

Computer network collection of autonomous computers interconnected by a single technology

A computer network is a digital telecommunications network which allows nodes to share resources. In computer networks, computing devices exchange data with each other using connections between nodes. These data links are established over cable media such as wires or optic cables, or wireless media such as Wi-Fi.

Barabási–Albert model

The Barabási–Albert (BA) model is an algorithm for generating random scale-free networks using a preferential attachment mechanism. Several natural and human-made systems, including the Internet, the world wide web, citation networks, and some social networks are thought to be approximately scale-free and certainly contain few nodes with unusually high degree as compared to the other nodes of the network. The BA model tries to explain the existence of such nodes in real networks. The algorithm is named for its inventors Albert-László Barabási and Réka Albert and is a special case of a more general model called Price's model.

In the study of scale-free networks, a copying mechanism is a process by which such a network can form and grow, by means of repeated steps in which nodes are duplicated with mutations from existing nodes. Several variations of copying mechanisms have been studied. In the general copying model, a growing network starts as a small initial graph and, at each time step, a new vertex is added with a given number k of new outgoing edges. As a result of a stochastic selection, the neighbors of the new vertex are either chosen randomly among the existing vertices, or one existing vertex is randomly selected and k of its neighbors are ‘copied’ as heads of the new edges.

Core router type of router designed to operate in the Internet backbone

A core router is a router designed to operate in the Internet backbone, or core. To fulfill this role, a router must be able to support multiple telecommunications interfaces of the highest speed in use in the core Internet and must be able to forward IP packets at full speed on all of them. It must also support the routing protocols being used in the core. A core router is distinct from an edge router: edge routers sit at the edge of a backbone network and connect to core routers.

EMMAN

EMMAN was a company limited by guarantee and jointly owned by its members, eight Higher Education Institutions in the East Midlands region of the United Kingdom.

Evolving networks

Evolving Networks are networks that change as a function of time. They are a natural extension of network science since almost all real world networks evolve over time, either by adding or removing nodes or links over time. Often all of these processes occur simultaneously, such as in social networks where people make and lose friends over time, thereby creating and destroying edges, and some people become part of new social networks or leave their networks, changing the nodes in the network. Evolving network concepts build on established network theory and are now being introduced into studying networks in many diverse fields.

The webgraph describes the directed links between pages of the World Wide Web. A graph, in general, consists of several vertices, some pairs connected by edges. In a directed graph, edges are directed lines or arcs. The webgraph is a directed graph, whose vertices correspond to the pages of the WWW, and a directed edge connects page X to page Y if there exists a hyperlink on page X, referring to page Y.

Torus interconnect

A torus interconnect is a switch-less network topology for connecting processing nodes in a parallel computer system.

Hierarchical network model

Hierarchical network models are iterative algorithms for creating networks which are able to reproduce the unique properties of the scale-free topology and the high clustering of the nodes at the same time. These characteristics are widely observed in nature, from biology to language to some social networks.

Bianconi–Barabási model

The Bianconi–Barabási model is a model in network science that explains the growth of complex evolving networks. This model can explain that nodes with different characteristics acquire links at different rates. It predicts that a node's growth depends on its fitness and can calculate the degree distribution. The Bianconi–Barabási model is named after its inventors Ginestra Bianconi and Albert-László Barabási. This model is a variant of the Barabási–Albert model. The model can be mapped to a Bose gas and this mapping can predict a topological phase transition between a "rich-get-richer" phase and a "winner-takes-all" phase.

Hub (network science)

In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.

References

  1. Siganos, Georgos; Sudhir L Tauro; Michalis Faloutsos (Dec 7, 2004). "Jellyfish: A Conceptual Model for the AS Internet Topology" (PDF). Retrieved 2007-12-29.
  2. "IBM Almaden - News - Researchers Map the Web" . Retrieved 2008-11-11.
  3. 1 2 Broder, Andrei; Kumar, Ravi; Maghoul, Farzin; Raghavan, Prabhakar; Rajagopalan, Sridhar; Stata, Raymie; Tomkins, Andrew; Wiener, Janet (2000). "Graph structure in the Web" (PDF). Computer Networks. 33: 309–320. doi:10.1016/S1389-1286(00)00083-9 . Retrieved 2018-04-02.
  4. 1 2 Metaxas, Panagiotis (2012). Why Is the Shape of the Web a Bowtie?. World Wide Web (WWW) Conference, WebScience Track. Lyon, France. Retrieved 2018-04-02.