Designing A Computer Network For Your Business: A Step-By-Step Guide
Designing a computer network for your business is a challenging project with many complex steps. However, like any other project, you can tackle it by breaking it down into smaller steps. The best method for network design is to follow a structured approach, clearly defining the requirements, and meticulously documenting each step of the process.
This blog post takes you through a step-by-step process for designing a computer network that is optimal, cost-effective, and fulfills your business requirements.
How To Design A Computer Network?
Here are the steps for designing a computer network for your business:
In the following sections, we will discuss each step in detail.
The first step in designing a network is to find out what the network is expected to do. This is a three-step process that defines where you are, where you want to be, and the resources available to help in the transition. In the context of computer networks, the three stages can be described as follows:
Describe Your Existing Network
In this step, you evaluate the existing network to identify the existing network infrastructure, components, and services running on it. This is done during a site visit and walkthrough and the following data is collected:
Types of network devices, including servers, and their locations
WAN technologies and circuit speeds
Cabling layout on the floor and within the building
Routing protocols, network management, and security controls.
This step is useful not just for gathering information that is used for designing your new network but also for determining if any existing network components can be used in the redesign.
Define The Goals For The New Network
In this step, you describe the target state of the network. These can be a combination of business and technical goals. Here are some examples:
Improve network performance metrics such as throughput, latency, uptime, etc.
Upgrade network to latest technologies
Improve network security
Simplify network management
Reduce downtime and improve network availability
Clearly defining your goals helps you stay focused on what the business needs and you are not likely to get distracted by all the possibilities available.
Define The Possible Constraints
For most small and medium-sized organizations the foremost constraint is budget. The budget impacts the equipment you can get and from our experience, that has a huge impact on network performance. Even when the budget may not be a factor, there may be limitations with respect to cabling, WiFi use, a business requirement to run legacy applications, or strict security and compliance requirements. All of these factors will impact your network design.
To deliver optimal network performance you need to know the size of your network, which means you need to know the number of devices and their intensity of use. Be careful not to fall into the trap of designing the network based on the number of users as each user may have multiple devices in addition to network devices such as servers, printers, VoIP phones, and IoT devices, all of which add to the bandwidth demand. Pay special attention to technologies such as streaming and virtual reality that tend to eat a lot of bandwidth.
Study your office floor plan and plot the exact location of all endpoints such as desktops, servers, printers, etc. This is necessary for determining the location of switches. You will also want to know the location of desks, meeting rooms, work areas, and any Wi-Fi-connected devices so that the location of access points can be determined. You will also need to inventory electric outlets, network jacks, and wall-mounted patch panels.
Thorough knowledge of your office layout will help you in designing an optimal network layout where devices are never too far from switches or access points. The location of endpoints will also help you quickly assign switches and/or ports to the right subnets.
Your choice of Internet Service Provider (ISP) can have as big an impact on your network performance as any other factor. Your network performance goals will determine the type of ISP subscription you need. Unfortunately, not all ISPs work seamlessly everywhere. The location of your office building will often limit the ISPs you will have access to. If you are working with a managed IT service provider, their experience and expertise will help you choose the most suitable ISP based on your location and requirements.
This step is the heart of your network design process. The design specifications will be the basis for the implementation phase and need to support the availability, security, and performance goals as specified in the requirements. Therefore, at this stage, you will create logical and physical topologies, network diagrams, and define specific design information such as routing protocols, IP addressing, subnets, and security configurations.
1. Network Topology
Using all the information you have gathered so far, you can draw your network topology, which is a structural arrangement of a network, where the network endpoints are depicted as nodes and the connection between them as links. This is an important phase in your network design process because the choice of topology has a major impact on the scalability, configuration management, monitoring, and general performance of the network.
Network topology is commonly designed using the top-down method, where you start from the top layer of the OSI model and work your way down. In this method, you start by analyzing the requirements of the application layer and adapting your network design based on those requirements. You can use CISCO’s PPDIOO methodology as a framework to keep your design process organized.
2. Network Type
An important factor in the design of your network is the physical extent of your network. Whether your organization occupies a section in a shared office, an entire floor of a building, multiple floors, or has offices in multiple locations, each case will require a different type of network. Your design can range from a simple local area network (LAN) to a complex wide area network (WAN) connecting multiple geographic locations.
3. Physical Network
The physical network consists of cabling, faceplates, patch panels, and similar basic infrastructure work. The type of cabling will depend on the type of network you select as well as on the performance requirements. Solid underlying network cabling is a prerequisite for efficient networks. You can plan your cabling to include devices such as printers, IP cameras, etc. in the wired network so as to free the Wi-Fi spectrum from wireless-dependent mobile devices.
You should also consider using Power over Ethernet (PoE), which allows you to deliver DC power to devices over copper Ethernet cabling. PoE eliminates the need for separate power cables and outlets for connected devices, thus offering expanded options for how and where network endpoints can be placed, simplifying your cabling work.
4. Network Equipment
Network equipment such as routers, switches, and hubs form the core of your network infrastructure. It is not possible to build a business network without switches because they connect together devices, such as computers, printers, and servers in the network. Routers, on the other hand, direct traffic, choosing the most efficient route for the data packets to travel across the network. It also connects your local network to other networks such as the Internet.
Having a clear understanding of the various network components, their purpose, and how they work is necessary for designing an efficient and reliable network. Your knowledge of these network components will also help you choose the right type of equipment for your networking needs.
We have discussed this in detail in our previous blogs:
How to build a computer network for your small business - Part 1
How to build a computer network for your small business - Part 2
5. Addressing and Subnetting
Until now we have dealt with the physical parts of the network and now we will be dealing with the logical part of the network. In this phase, you will assign IP addresses to your networks. Each device connected to the network has its own IP address. The IP address assignment can be either static or dynamic, depending on your network practices and features. The Dynamic Host Configuration Protocol (DHCP) is the most commonly used protocol for automatically assigning IP addresses to network-connected devices.
For effective network management, resource allocation, and security reasons, your network is likely to be divided into sub-networks or subnets. The network endpoints may be assigned to a subnet based on their location, department, function, or any other criteria.
When designing a network, the most important thing to remember is that you cannot design the entire network in your head. You may think that you just need to link up your network equipment and things will work fine. But that’s never the case in a business environment, which is highly complex. Every device that you add to or remove from your network impacts its performance.
Therefore, it is highly recommended to document each and every step of your network design process. A clear plan and physical diagram will ensure that you do not miss any important aspect of the network and more importantly, will help in the implementation of the network.
Your design document should include the following:
The project’s goals.
Design requirements and constraints.
Details of existing network infrastructure including topology diagrams, network performance metrics, routing protocols, list of applications running, equipment list, and configurations.
Network design details including logical and physical topology, network diagrams, IP addressing, routing protocols, and configurations.
An implementation plan detailing the steps for the new installation, settings, and configurations.
By now you should have a general understanding of the various steps involved in network design. But once you embark on the design process, you will come across multiple questions, hurdles, and challenges. Many of these can be avoided by using best practices that have already been tried, tested, and used for many years.
Here are some important network design best practices:
1. Plan For The Future
The demands on your networks are always growing. In times of growth, there will be a sudden increase in the number of users and devices. At other times, organizations may be adopting new technologies such as video conferencing, virtual reality, and IoT devices that use up a lot of bandwidth and cause network congestion. Therefore, it is prudent to err on the side of caution and consider additional network load to accommodate the growth and adoption of new technologies in the future. The usual practice is to calculate based on the capacity you might need in the next year or two.
2. Backup And Failover
No matter how well we design a network to be, like any other device or technology, it is liable to break down due to the failure of or error in one or more of its components. Even when the network itself is stable, the ISPs tend to suffer from outages from time to time. You can safeguard against such breakdowns and outages by building redundancies into your network.
Redundancies built into your network core will ensure that the network will be up and running even if there are any issues with one or more of its components. The redundancy can include an alternate power supply, additional cabling forming multiple network paths, and a secondary backup ISP subscription.
3. Embed Security In Your Design
Anyone with access to your network has access to virtually your entire infrastructure. Therefore, you need to take network security very seriously and include it in your network design right from the start. We have talked about network security at length in the following blog posts:
4. Network Design Is Never Finished
Your job with the network is never really done. Even after you have implemented the network, you still need to verify that it meets the goals initially established, monitor the performance, ensure security, and apply tweaks as and when needed. Also, there is always the need to add new services and features that will impact the performance of the network. So you will need to keep modifying, updating, and maintaining the network.
Conclusion
Network design is a complex project and the complexity varies depending on the size, topology, performance requirements, geographical extent, and many other factors. Nevertheless, the design process described above gives you a framework you can start with no matter the size or complexity of your project.
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