Network design

How to design a local network

Editor’s Note: If your customer wants you to design a local area network, there are many tasks to accomplish – working through a network hierarchy that stretches from the access layer to the core, determining which subnet mask to use, and, in general, learn the client’s networking conditions. This network design checklist provides tips on how to create a local area network. So, establish these network diagrams and get to work.

You finally have the consulting project you’ve been waiting for: A client is building a new office and asked you to design their entire local network (LAN) because their current infrastructure is obsolete and ports are breaking down every day.

It’s a consultant’s dream! However, it can become a nightmare for you and your business if you design the network incorrectly.

The following network design checklist examines some of the major network design issues to consider when designing a new local area network for your customers.

Plan the complexity of the network to be in line with the customer’s IT expertise

Switches and routers come with hundreds of features and functions. However, engineering too many bells and whistles in the network can create support issues in the future if customer IT staff do not have a basic understanding of the features and functions you are implementing. Recognize the needs of the business without making the network too complex.

To PoE or not to PoE?

More and more customers are deploying wireless network technology and IP telephony. Wireless LAN access points are easier to install when Power over Ethernet (PoE) is available. IP telephony uses phones that connect to the local network and draw power from it. The days of the traditional private branch exchange (PBX) system are numbered; all suppliers are moving towards IP PBX Systems and combined. Many customers will tell you “We are not using wireless” or “We will never switch to IP telephony”. That might not be the case now – at least to their manager’s knowledge – but if you do a good job on this project, your client will keep their equipment for at least three to five years. You will be doing your customer a great service if you can convince them to buy PoE switches now. Then, when the CIO decides to switch to wireless LAN or IP telephony in 18 months, the non-PoE switches will not need to be replaced.

Determine network needs

Just because 10 gigabit Ethernet is here today and higher speeds are coming, doesn’t mean you need these ports throughout the local network. Too often, customers buy the fastest equipment possible thinking they need it, even if their existing 100 Mbps network is only running at 5% capacity. While it is certainly prudent to ensure that the primary switches can support these higher speeds, you might be advising the customer to waste a lot of money if you tell them 10 Gb switches are needed everywhere.

Wireless LAN technology refresh and upgrades are among the top networking initiatives of 2018.


Network availability becomes more critical every year. Spend time planning a design that offers network redundancy from a physical and logical point of view. For example, use dual fiber optic uplinks between wiring closets and main switches. Make sure that the central chassis-based switches have two CPU boards. Make sure to think about things like default gateway redundancy. You can design the most redundant physical network in the world, but if it is not properly configured to provide Layer 3 Default IP gateway redundancy and an outage occurs, your customer’s network will suddenly shut down and you can be sure they will call you and ask you why.

Standards and maintenance

When design of a corporate network, try to standardize a few different types of devices, rather than using a different type of switch in each wiring closet, even if all of your equipment is from the same manufacturer. Standardization on a few different types of hardware simplifies configuration and troubleshooting. It also allows the customer to keep spare parts cold for each device with next business day maintenance, resulting in faster and more economical responses to device failures.

Network management tools

While these always seem to be left out in purchase orders, network management tools are invaluable in providing maximum network uptime. Software that periodically backs up all device configurations to a share on the network is simple but extremely useful. Also consider the following scenario: Two switches provide default IP gateway redundancy on your customer’s network. One of them fails, but you don’t realize it because the network is redundant. When the other fails, the client suffers a total network failure. This can be easily avoided by using a simple tool to ping all network devices and report their status.

There are a lot of other things to consider when designing a local area network for your customer. This network design checklist covers some of the most important ones that will hopefully point you in the right direction and, more importantly, provide you with a happy and loyal customer.

TechTarget network planning resources beyond this network design checklist include this feature on simplify overly complex networks and this preview of data center network design.

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