Design and Implementation of a Scalable and Secure Network Infrastructure for a Medium-Sized Enterprise

1. Introduction

Much of the business function in the modern digital world hinges on the reliability and scalability of a network infrastructure on which it operates. This particular work is in line with the development of a complete network system into an enterprise that has an average of about thirty employees or varied operational departments. The main objective of erecting this network is to ensure that it is secure, efficient, and scalable according to the present needs of the business, but more importantly, it should not constrain tomorrow’s growth [1,2,3].

The design therefore translates into a two-story facility where the first story is to host servers and the printing office, while the second would comprise the interior department’s Finance, Sales, Customer Service, IT, and executive functions. A structured network topology that is a ring is designed for high availability and high-speed data transmission while minimizing the effects of collision and consequently providing good performance across departments. Effective traffic management and simple network administration can be achieved through the strategic planning of IP addressing and subnetting. Security is assured by careful physical access and future planned firewall installation. This report provides floor plans and network diagrams as well as justification for design choices, static routing tables and the chosen topology: all serve to demonstrate a sound basis for digital operations in the enterprise [4,5].

The floor plan provided for mid-size company is shown in Figure 1. The first floor has not been developed to accommodate employees as it is dedicated to the servers. Further, it has a printing area to perform bulk printing. An area to sit is provided to connect the server and printing room for the visitors managing the server or waiting for the printer. The floor provides wireless connectivity to the internet for its visitors. Moreover, a key card machine will be established to keep unauthorized persons at bay from entering the premises. Visitors like maintenance crew have the privilege to avail of our premises ensured by entry along with one of the employees for privacy and security for our company [6].

Figure 1. Floor 1 Floor Plan.

Figure 1. Floor 1 Floor Plan.

Figure 2. Floor 2 Floor Plan.

Figure 2. Floor 2 Floor Plan.

Alongside granting an independent working space for each department, a maximum capacity of 30 employees can therefore be accommodated on level two. In addition, we’ve allocated a surveillance room and a CEO’s office. Just for a little extra, we also provided a meeting room for 20 employees in departmental meetings or some discussions needing more than one department. This floor also accommodates a prayer room and restrooms for both genders. Key card access is further in place for this floor so that unauthorized individuals cannot access it [7].

Figure 3. Network Diagram.

Figure 3. Network Diagram.

There are 4 subnets in the network with 30 PCs, 6 Printers, 2 Access Points, 5 Servers, 4 Switches and 4 Routers. The default gateway for floor one will be 192.168.11.1, for the Sales and Finance department is 192.168.31.1, for the Customer Service and IT department is 192.168.51.1 and for CEO’s room, Meeting rooms and surveillance room is 192.168.71.1. Network devices will be in their department. Furthermore, each communication between routers has its own network. R1 and R2 are using the network 192.168.101.x, R2 and R3 are using the network 192.168.102.x, R3 and R4 use 192.168.103.x and R4 and R1 use the network 192.168.104.x as show in Table 1 and Table 2.

2. Literature Review

Network topology is a key aspect of developing scalable and fault-tolerant enterprise networks. Ring topology, which is used within this project, has each machine connected to only two other devices through a ring-shaped data path. According to authors recommendations [8], this topology achieves effective data transmission as traffic flows in a single direction, which reduces packet collision and aids in load balancing. Moreover, fault detection and isolation are simpler for ring topologies since network monitoring software is able to identify and correct connection faults instantly [10,11].

The use of static routing in this architecture supplements the inherent ring structure. Static routing is preferred in small, well-organized networks with lower change rates. Static routing simplifies routing tables and improves predictability [12]. Although it lacks the flexibility of dynamic routing protocols, simplicity supplements inherent performance constancy, making it suitable for medium-scale business organizations with pre-coded traffic behaviors.

IP addressing and subnetting techniques also occupy a core role in network effectiveness and security maintenance. In every subnet, the subnet mask 255.255.255.0 was chosen to have a large number of hosts per subnet and to maintain organized traffic control by departments. The Network Seal [13] declares that these subnetting schemes in Class C networks allow for growth scalability and simple IP management.

Local Area Networks (LANs), such as the one established in this project, benefit from structured segmentation by departments, with their own IP blocks. This not only improves security but also permits easier fault identification and maintenance. As the outlines, structured LAN designs using segmented topology and distributed switches lead to improved performance and expansion readiness [14].

Overall, the literature confirms the network design rationale—favoring ring topology, static routing, and departmental subnetting—as suitable for a growing medium-sized company in need of performance, scalability, and fault tolerance.

3. Methodology

The approach used in this project was a systematic network planning method, beginning with the analysis of the physical layout and proceeding through to logical network configuration. The first phase was requirement gathering, where the needs of the company were established in terms of the number of employees, departmental structures, and expansion in the future. Based on floor plan analysis, certain of the key features such as a dedicated server room, departmental segregation, and restricted access were included to satisfy functionality along with security [15,16,17].

Subsequently, the appropriate network topology was selected. Ring topology was implemented after extensive research and keeping in mind the fault tolerance, scalability, and best data routing requirements of the organization. This choice is in favor of medium-sized company local area network (LAN) best practices that provide a stable and expandable infrastructure [18,19,20]. Following the determination of the topology, IP address planning and subnetting were undertaken. A logical IP addressing scheme was devised, allocating four separate subnets to different departments: 192.168.11.0/24 for the print and server area, 192.168.31.0/24 for Sales and Finance, 192.168.51.0/24 for IT and Customer Service, and 192.168.71.0/24 for the CEO office, Meeting Room, and Surveillance. Each subnet utilized a default subnet mask of 255.255.255.0 for a maximum of 254 usable hosts, leaving space for expansion.

Static routing configuration was then implemented using manual routing table configuration in each of the routers that formed the ring topology. This gave direct control of department-to-department traffic and minimal routing overhead, which reduced complexity that typically comes with dynamic routing protocols. Device allocation and network segmentation were then performed, where switches and routers were assigned according to department layout and estimated device load. Each hardware item, including PCs, servers, printers, and access points, had a static IP address assigned to avoid conflicts as well as network management issues.

For more robust physical as well as network security, key card systems were introduced at central access points on both floors. Secure Wi-Fi access was also recommended with log-in credentials, along with the introduction of adding a firewall at later stages to provide better security for data and user privacy too. Finally, the network configuration was confirmed by generating simulated network maps and detailed IP addressing tables. These graphical and tabular representations ensured readability, confirmed the functionality of the setup, and facilitated documentation of the overall network structure.

This Figure 4 depicts the static routes that have been set up on Router 1. These routes define the paths used in order to reach different subnets across the network, so that information meant for Finance and Sales, Customer Service and IT, and CEO’s office networks will be routed efficiently. Router 1 is one of the central nodes in the ring topology and a key intermediary in allowing inter-departmental communication.

Figure 5 show the Router 2’s static routing table, as shown here, contains entries that allow it to forward packets to their respective neighboring routers and departments. This is crucial in maintaining the logical flow of traffic and allows for the ring topology’s redundant data paths that enhance fault tolerance.

Figure 6 depicts Router 3’s routing setup that gives good data delivery to the Customer Service and IT department. Router 3 is connected to Router 2 and Router 4, continuing the ring’s logical loop and ensuring a continuation of communication even if one link is severed.

Above Figure 7 shows the Router 4 closes the ring by returning to Router 1 and by continuing its connections to the CEO’s office and security systems. Its static routing table helps in smooth communication in the network and offers backup routing paths in case of failure of other segments.

As illustrated in Figure 8, this network design is based on a ring topology. The subnet mask for this network is 255.255.255.240 which can support a maximum of 16 hosts. There are 4 routers being used in our current design, but additional routers can be used if the company wants to extend the company to other floors using the assistance of other IP addresses.

According to the NetworkSeal (2016), the table below demonstrates some subnet masks and their host capacity. The table is a guide to why the subnet mask 255.255.255.0 was chosen to be used in the internal departmental subnets, giving 254 usable host Ips per subnet. This allows for departmental growth and offers redundancy for network growth.