A Study on Topology in Computer Network

Qing Liu1, Qiuping Liu21Jiangxi Applied Engineering Vocational Institute, Jiangxi Pingxiang,337000,china

2Pingxiang University,Jiangxi Pingxiang,337000,china63032688@qq.com

Abstract-It is well known that well learning thecomputer network topology and its development trendis keenly important in the research of next generationnetwork It is necessary in a correct understanding ofthe current computer network development status andnetwork system structure based on the meaning andexpansion to meet the next generation networkdevelopment needs of a new generation of networkstructure research. Therefore, this article analyzed thecomputer network and current situation of thedevelopment of the computer network. In recent yearsthe evolution and development of computer networkare summarized and analyzed by focusing on themeaning of network system structure deeply andwidely. The conclusion of this article is important andkey to guide the next generation of computer systemnetwork.

Keywords- Computer Network; Next generationnetwork; Topology

1. IntroductionComputer networks have developed and obtained

huge achievements during past decades. In particular, as atypical representative of computer network Internet is aglobal, open integration, that anyone can use multiplenetwork applications across heterogeneous networks. Ithas deeply impacted politics, economics, technology andculture world widely. However, in recent years, withcommercialization of the Internet, emerging of newnetwork technologies, and the widely used Internetapplications of the rapid development, some flaws ofcurrent Internet structure have been emerged increasinglyvisible and prominent [1]. For example of the quality, it isdifficult to guarantee that service will be flexible. Thecustom network transparency is gradually lost. Someother problems are obvious, such as lack of security, moreand more complex hardware and software, twisted-tussle[2], are now growing intensified. There are some

indications show that, at this stage of the Internet,computer network has never been demonstrated by thesuccess and prosperity, while the corresponding structurehave also demonstrated the fragility and inadequacy thanever before. Correct understanding of the current status ofthe computer network, computer network, the trend ofdevelopment in different directions, and the review ofcomputer network structure, and the meaning of researchto built the next generation of network developmentneeds of the new generation network structure. Therefore,the reference of current network structures will be animportant guide.[3]

2. Summery of Network structureThe most famous network structure in current status is

Open Systems Interconnection model (OSI model), whichis a product of the Open Systems Interconnection effort atthe International Organization for Standardization. [4-6]This is a way to divide a communications system intoseven smaller parts which are called layers. Each layercontains similar functions which could provide servicesto the upper layer and receives services from down layer.On each layer, an instance offers services to the instancesat the upper layer and requests service from the downlayer.[7-10] The seven layers are shown as follows:

Physical LayerThe Physical Layer is regarding the electrical and

physical specifications for devices. The physical layersupplies an electrical, mechanical, and proceduralinterface to the transmission data. In particular, it definesthe relationship between a device and a transmission data,including voltages, hubs, adapters, and so on. This layermainly supplies the transmission of data.

Data Linking LayerThe Data Link Layer defines the functional and

procedural means regard data between network entitiesand to detect errors. As well this layer will correct theerror as far as possible. Originally, this layer was intendedfor P2P and P2M data. For local area network structure,this layer usually includes broadcast-capable multi-accessdata. In real practice, sliding window is only used in, butnot flow control. A famous application of sliding-window

2014 7th International Conference on Intelligent Computation Technology and Automation

978-1-4799-6636-3/14 $31.00 2014 IEEEDOI 10.1109/ICICTA.2014.18

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2014 7th International Conference on Intelligent Computation Technology and Automation

978-1-4799-6636-3/14 $31.00 2014 IEEEDOI 10.1109/ICICTA.2014.18

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2014 7th International Conference on Intelligent Computation Technology and Automation

978-1-4799-6636-3/14 $31.00 2014 IEEEDOI 10.1109/ICICTA.2014.18

45

2014 7th International Conference on Intelligent Computation Technology and Automation

978-1-4799-6636-3/14 $31.00 2014 IEEEDOI 10.1109/ICICTA.2014.18

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flow control is TCP, but this is still used in niches withgood performance. In another word, its main task is toproduce and recognize the frame boundary of data. Thiscan be conducted by attaching special bit patterns to thewhole progress of the frame. The input data can bedivided into different frames.

Network LayerThe Network Layer mainly provide the functional and

procedural means of transferring variable length datasequences on a different network, while guaranteeing thequality of service requested by the Transport Layer. TheNetwork Layer supplies network routing functions, andreport errors. Routers work at this layer to send data byusing the extended network. Actually, this is a logicaladdressing scheme according to the values chosen byengineers or workers. The progressing is not hierarchical.It operates subnet and determines the routing strategies.

Transport LayerThe transport layer receives reliable data from upper

layers and transfers data between end users. TheTransport Layer determines the reliability of a given linkby using flow control, segmentation/de-segmentation, andtolerant of error. Some protocols are state and connectionoriented.

The Session LayerThis Layer provides a user interface to the network

where the user negotiates to build a connection. The usermust supply the remote address to be contacted. Its majorwork is to transfer data from the other application to thisapplication so that this is mainly utilized for transferredlayer.

Presentation LayerThe Presentation Layer build context among all

Application Layers, that the upper layer may utilizedifferent syntax and semantics if the presentation serviceprovides a mapping between them.

Application LayerThe Application Layer is the OSI layer closest to the

end user, which means that both the OSI application layerand the user interact directly with the softwareapplication.

3. Analysis of Internet TopologyIn current main network structures, there are main

eight basic topologies: Point-to-point, Bus, Star, Ring,Mesh, Tree, Hybrid, Daisy chain.[11-17] The detailedinstructions are given as follows,

Point-to-pointThis structure is also called P2P. This is a famous

network structure. The simplest topology is a permanent

link between two endpoints. The value of an on-demandP2P connection is positive proportional to the number ofpotential pairs of network nodes.

Bus

Fig1 Bus network topology

The structure of BUS is shown in Fig 1. This kind ofstructure is widely used in local area networks. In thisstructure, each node is connected to a single cable. Inpractice, each CPU or server is connected to the singlebus cable. Signals from the source transfers in positiveand negative directions. Throughout this method, bothCPU or severs can be connected the bus cable. As wellthis kind structure can be intended with extra recipient.

Star

Fig 2 Star network topology

Another well used topology in local area networks is astar topology. A central hub connected distribute networkhost with a P2P connection method. In this topology,every node is connected to central node called hub orswitch. The switch is the server and the peripherals arethe clients, which are shown in Fig 2. The advantage ofthis kind topology is the simplicity. It is convenient toadd additional nodes, while the most obviousdisadvantage is that the hub is the weakness of the whole

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network. If the central hub be destroyed, the wholenetwork won't work any more.

Ring

Fig 3 Ring network topology

The Ring topology is shown in Fig 3. Each deviceincorporates a receiver for the incoming signal and atransmitter to send the data on to the next device in thering. The network is dependent on the ability of the signalto travel around the ring. Actually, if the scale of networkis huge, any two nodes will destroy the connection of thewhole network.

MeshThis structure can be cataloged as two situations

according to the connection method. One is fullyconnected and the other one is partially connected. Theoverview of the two kinds are shown as follows,

In Fig 4, the figure is shown the situation named Fullyconnected

Fig. 4 Fully connected mesh topology

The number of connections in a full mesh = n(n - 1) /2.

Fig.5 shows the situation named partially connected.p y

Fig 5 Partially connected mesh topology

The type of network topology in which some of thenodes of the network are connected to more than oneother node in the network with a point-to-point link thismakes it possible to take advantage of some of theredundancy that is provided by a physical fully connectedmesh topology without the expense and complexityrequired for a connection between every node in thenetwork.

Tree

Fig. 6 Tree network topology

The type of network topology in which a central 'root'node (the top level of the hierarchy) is connected to oneor more other nodes that are one level lower in thehierarchy (i.e., the second level) with a point-to-point linkbetween each of the second level nodes and the top levelcentral 'root' node, while each of the second level nodesthat are connected to the top level central 'root' node willalso have one or more other nodes that are one levellower in the hierarchy (i.e., the third level) connected toit, also with a point-to-point link, the top level central'root' node being the only node that has no other nodeabove it in the hierarchy (The hierarchy of the tree issymmetrical.) Each node in the network having a specificfixed number, of nodes connected to it at the next lowerlevel in the hierarchy, the number, being referred to as the

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'branching factor' of the hierarchical tree. This tree hasindividual peripheral nodes.

HybridHybrid network is a combination of two or more

topologies mentioned above. By combination, eachnetwork does not exhibit one of the standard topologies.For example, a mesh network connected to a meshnetwork is still a mesh network topology. However, ahybrid topology is always produced when two differentbasic network topologies are connected.

Daisy chainThe main advantage of daisy chain is easy to add

more computers or servers into a network by connectingeach computer in series to the next. Data will be intendedfor a computer partway down the line, each systembounces it along in sequence until it reaches thedestination.

4. ConclusionsIn this paper, we mainly discussed the main stream

network topology structures. We present the mainadvantage and disadvantage about the eight structuresmentioned above. According to the analysis, we know thecharacters about different architectures so that it isconvenient for us to build new network in practice. Aswell all the conclusions are meaningful for engineers todevelop the next generation network.

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