Physical topology defines the physical layout of the network components in a network while logical topology is about the flow of data from one component to another on a network. There are five main types of physical topologies that we can choose from when implementing out network infrastructure. The selection of the physical topology will be based on the ability of the topology to ensure that scalability is achieved. There is also a key question maintaining, the topology should enable the network administrator to easily configure and trouble shoot whenever there is a problem. Examples of physical topologies include; bus, ring, star, mesh and hybrid topology. They are implemented by organizations based on their needs. The physical topology that will be implemented for this project is tree or hybrid topology. This is because tree topology allows expansion of the existing network infrastructure. This means that if there will be a need for the organization to expand the network it will be very easy. Tree topology combines the capability of star and line or bus topology. This means that it has the benefits of two network topologies combined together. The figure below shows the hybrid or tree topology that has been selected for this project.
Fig. 1 Tree topology
As stated earlier, star topology and bus topology capabilities are combined to form tree topology. The topology has small or grouped star topology joined together with each other through a bus or a large network cable. This is the perfect design because the organization has different departments and sections that are on different building and areas. A single star topology can be implemented for a given department. This ensures that if the employees want to access information within their department it will be faster. It will also be easy to manage other departments that do not need connection to other departments. For instance, it will be required that the finance department network is not accessible by the other departments or employees hence it can be removed or set protocols of accessing the network. It will also ensure that security is enhanced at different levels of the organization.
Tree topology is also supported by many hardware and software vendors. This means that it will not be a problem to get the required components to set up the network. There are segments that allow connection of individual networks. This ensures that there is quick transfer in data or exchange of information by the users. The other reason for selecting this network is the incorporation of the line topology which is cheaper to install and maintain. The cost of purchasing concentrators is eliminated. The bus or linear topology reduces the length of cables needed. This is because all computers are connected to each other through a bus cable. This means that we only need short cables to connect the bus and the computer. It is easy to expand the network with star topology. This is possible by just adding more connectors on the network.
The logical topology that will be implemented will be bus logical topology. This is because of the type of media that will be used to network the organization. Ethernet normally uses bus logical topology with a combination of bus, star and point-to-point physical topologies. The logical topology selected is a perfect match for the selected physical topology.
Network security concerns of the organization are a very serious issue that the CIO has considered. The current network infrastructure is becoming more complex by the day. Many years back it was easy to secure network and computer systems because there were few people who accessed a computer network. Simple measures such as physically securing the building where computers are stored were enough to secure data and information stored and processed. Computers are becoming smaller in size making it hard to secure in an organization. These computers are also connected to the internet using wireless technology making it more difficult to secure them.
In the past like fifty years back organizations did not contact their business across the internet. Issues of online banking and shopping were far from becoming a reality in those early days of network invention. Currently million transactions are done daily by a many people. There is overreliance of business to transact businesses is becoming beyond control. Million of money is transactions each day over the network through the bank and credit card purchases. Fraud and theft are the main network problems that many network administrators face today. This is motivated by the large amount of money transacted only and value of information if intercepted.
The nature and requirements of network security has changed rapidly over the past years because of the continued security issues it faces. Network security is becoming more demanding because of the shift in the factors that contribute to insecurity from network level threats, connection-oriented attacks ad denial of services (DoS), contend-based threats like Viruses, Worms, Trojan and Phishing. The key question is what are the modern trends in network security? There are several trends as detailed below.
Just as stated in the introduction there has been rapid change in the network structure. The network structure of 20 years ago could be comprised simple LAN connection to the WAN connection and few remote access points. Currently the network environment is comprised of many access points such as 802.11 wireless and Local Area Network LAN with many portable devices such as laptops, personal digital assistance and smart phones. The current network is also full of web portals, file transfer protocol FTP servers, email servers and end-users accessing the network with modern communication tools. The treats to the network are presented in figure 2 below.
The modern trends in network security can also be looked at by looking the changing trends at work place. Workforce is becoming more mobile where people are able to work from home; the telecommuters and mobile office work those who are not in the same location for a longer period. This is a new trend to network security.
Figure 2 security of the network: complexity of network structure (source: www.esoft)
Network applications are rapidly becoming more sophisticated. For instance when Windows NT was deployed it only had 5 million lines of code in 1994 but few year later, Windows Vista was launched with 50 million lines of code representing 1000% growth which is very huge. Server systems become more vulnerable with the complexity in the applications. Attacks are also on the same trend of increased complexities. Attacks in early 2000’s was simple on the Denial of Services but currently is has become more complex in targeting server systems.
There is a need to look at how to ensure that there is integrity and confidentiality of data collected. This means that the organization must come up with clear policies because the company deals with sensitive information. Since all the computers of the organization will be connected and accessed by the employees from any point. There are high chances that data integrity will be a big issue. There are those who will want to take this opportunity to accomplish their malicious acts. The threats are both internal and external. The firewall, antispyware and antivirus are will be implemented to deal with external data breach attempts. This means that the network administrator will be able to ensure that only authorized used access files externally if they have the authority. Those who may want to attack the network and bypass the security of the network will be handled by the up to date software applications.
The issue of internal security will be enforced by access control mechanisms. The first security measure will be the physical access to the computer rooms by the employees those who have the credentials will pass through the door and those who do not have the access to the room will be restricted. The use passwords to access the information in the system will also be use to ensure that users can only see what they are supposed to see. The system log files will be used to ensure that network resources are used according to the policy and regulations of the organization.
This project has selected the network structure that is needed by the organization. Bus logical topology is used because of the type of media and quick transfer of information between users. Tree topology which combines the star and linear topology capabilities is implemented at the physical topology. The key question of security is addressed by enforcing security measures. Ethical consideration has also been addressed by coming up with regulations on how data is accessed, utilized and shared among the stakeholders. The network plan is clearly designed to allow future expansion of the network.
Reference
Simeonidou, D., Nejabati, R., Arnaud, B. S., Beck, M., Clarke, P., Hoang, D. B., & Travostino, F. (2004, October). Optical network infrastructure for grid. InGrid Forum Draft, GFD-I (Vol. 36).
Appendix
Fig. 2. Components of the network infrastructure
Fig 3. security appliance that requires for the netwok (source: www.esoft)
Fig. 4. Communication within a single star topology of the organization
