In the world today, information communication and technology has become one of the most relied upon pillars for economic development. It is through technology that the entire universe has been reduced to a small village whereby persons far away from each other can interact freely on real-time basis. Hence, every business enterprise and institution for instance is gearing towards modernizing its operations through Information technology.
As a result, one of the most vital resources to ensure Information technology revolution is and has been using computers. They have replaced and /or improved the working environment through recording, processing, and analyzing data by utilizing application software. It is that this point that the pre-requisite IT infrastructure comes in handy. Thus, internet facility is required to interlink various departments within an organization so as to improve efficiency.
However, to put in place the network infrastructure, a number of requirements and constraints have to be considered and includes the type of organization, desired network -its cost and reliance, and financial costs among others. The networking topology consists of two parts; physical and logical design networks, which are utilized further in various forms; bus, mesh, star, and ring network topologies (Raza, 2002). Each one of these has got its pros and cons. Hence, it is imperative while embarking on a mission to set up a network infrastructure, research extensively in order to determine the most feasible type. This has been covered to detail in the literature ahead to distinguish logical and physical design networks as well as related terminologies through a library based research.
The network topology refers to the layout of a network installation (David, & Skandier, 2005). The layout consists of two parts. First one is the physical network design which refers to the actual arrangement of all the devices that that are connected to the particular network. This is inclusive of the network location and cables installed. Second is the logical network design which refers to the way in which the network appears in the devices within the network or how data is transmitted within the network (Siamwalla, Sharma, & Keshav, 2000). These two types of layouts are consists of four different kinds of network topologies in network infrastructure is set up. These include, the bus, mesh, ring, and star topologies (Raza, 2002).
Types of network topologies
A mesh topology represents a Wide Area Network whereby there are quite a number of paths interconnecting various sites. In this topology, a router is used in identifying and determining which path is best for data transmission. For a simple network, for instance two to three sites, it is convenient to create but for quite a number of sites it becomes expensive. Reason being that every network site and subsequent additions of devices needs an independent cable connection. Besides, the amount of work involved while configuring network is cumbersome (Programming Languages: Logical and Physical Network Design, 2004); However, the biggest advantage with mesh network is that, in case one of the connections fails, it does not interfere with the rest. Mesh topology represents a physical design layout.
The bus topology in most cases is either a physical and/or logical design network. It generally utilizes Ethernet cables to connect and it is considered the simplest among the others. A backbone -common cable- is connects all the devices in a given network and any other device that is being added is connected to the same cable. It is therefore economical to implement as only one cable is used. The backbone connection transmits data through only this particular cable and interruption leads to disconnection of the whole network.
The ring topology is a physical design layout whereby each device in the network is connected to its two other neighboring devices. However, in case a new device is being added, the whole connection is disrupted and this involves a lot of work to configure the whole system. Nevertheless such conflicts in transmitting the data can be mitigated by applying token ring technology but this m, method is rarely used in setting up a network (Designing a Network Topology, 2004).
The star topology is usually either a physical and/or logical design layout whereby network devices have got one central location referred to as a hub or switch. This topology is the most advantageous because if one of the devices fails, the others are not affected. Configuring the network is simple as any one cable can easily be connected to the hub or switch. It is usually applied in Ethernet networks. Furthermore, all of these network topologies can be used in one single network to form a hybrid network topology (Thomas, 2008).
Differences between logical and physical network designs
Physical design layout outlines the pieces of the logical design network which are in a given network architecture. Besides, it refers to the arrangement of computers and other physical components. Its components include Fiber, ISDN and Ethernet (Johnson, 2002). The logical design network assumes a particular piece of a conceptual design in a network and assigns it a logical role in a within that framework. Its components consist of IP structures of the network such as Class A, B, or C address scheme (Johnson, 2002).
Factors to consider when designing a network
For a good network design the strategy and planning components are very vital. The overall project needs to be implemented in an orderly manner in order to achieve the goals set.
Policies should be put in place when designing a network (Network Diagrams, 2010). They stipulate to detail how the network resources are to be used by the users concerned. Another scenario that policies become a necessity is at a point when network security becomes paramount -for instance firewall technology (Designing a Network Topology, 2004). Technical users responsible for managing the network require adequate training on tasks to be undertaken in the network management. When designing the network, the cost of the budget should be a pre-requisite consideration as well as the benefits to be realized. Feasibility study should be carried on both costs and benefits (Network management reference architecture, 2010).
To design a logical network, there are two options; one can either design/install a new network from the scratch or upgrade an already existing logical network. However, a number of factors are supposed to be considered before commencing the design work: What services will you be providing to the clients/users? What possible network traffic patterns that crop up as a result from your particular plan? What are the expected bottle necks and how to avoid? Another important consideration is to determine whether your internet connection is going to be for internal network users only or if outside users’ domain will be given access to the network resources (Network Tutorials, 2010).
In addition, scalability and extensibility of the network design are crucial considerations. Hence factors such as: Economic constraints -in most cases one has to compromise the capability of Wide Area Network links, the switching routers’ capabilities, the kind of interfaces used, and at some instances the of redundancy achieved; Labor-in either of the network design, the degree of effort and the level of knowledge required to admit a new client to the new network and/or expand the capacity of the network infrastructure are of great concern (Craft, 2006); The processor speed -increases on regular basis and therefore makes the internet traffic levels to rapidly increase. Computational limitations that most often engulf any particular network design are correlated to processing of route updates, security filtering, encryption, translation of address and packet forwarding; Space consists of the value of air-conditioned points of references (POPs) an/or the collocation facilities (Scots & Ogletree, 2003); Time-to-market is another issue to be considered as while designing a network, clients might be have looked for alternatives by the time it becomes operational (Mueller & Ogletree, 2003).
Designing a network calls for meeting the necessary requirements and constraints and putting into consideration other external factors for instance, cost of setting up the network, scalability and extensibility, and the future prospects of the particular network design. Nevertheless, the choice of the network design depends on its reliability and the resources are available for its adoption.
Craft, M. (2006). How to Cheat at Designing a Windows Server 2003 Active Directory Infrastructure. Syngress.
David, G., Skandier, T. (2005). Network+ study guide, fourth edition’. Sybex, Inc.
Designing a Network Topology. (2004) .Cisco Press & Priscilla Oppenheimer. Retrieved
February 15, 2010, from www.topdownbook.com/chapters/Chapter05.ppt
Network Tutorials. (2010). Retrieved February 14, 2010, from
Network management reference architecture. Retrieved February 14, 2010, from
Mueller, S., & Ogletree, T. (2003). Network design strategies; Planning and design components.
Upgrading and repairing networks. (4th ed.) .Que. Retrieved February 14, 2010, from
Megaessays: Network topology. Retrieved February 14, 2010, from,
Network Diagrams. Retrieved February 14, 2010, from,
Johnson, J. (2002). Ask the Networking Expert: Questions & Answers. Retrieved Feb 14, 2010,
Network Topologies, Retrieved February 15, 2010, from
Programming Languages: Logical and Physical Network Design. (2004). Retrieved February 15,
2010, from http://www.cheathouse.com/essay/essay_view.php?p_essay_id=47389
Raza, K. (2002). Cisco Network Topology and Design. Cisco Press. Retrieved February 15,
2010, from http://www.ciscopress.com/articles/article.asp?p=25188
Siamwalla, R., Sharma , R., & S. Keshav (2000). Discovering Internet Topology. Cornell
Network Research Group Department of Computer Science Cornell University. NY:Ithaca.
Scott, M., Ogletree, W. T. (2003). Upgrading and repairing networks. (4th ed.).Que. Part of the upgrading and repairing series.
Thomas, S. (2008).Network design checklist: Six factors to consider when designing LANs.
Retrieved February 14, 2010 from