Four tips for network capacity planning and configuration

When designing an enterprise network, there is a fine line between under-provisioning and over-provisioning network resources. However, for many network architects, they worry more about not having enough network resources than about configuring too many.

This concern can result in networks with performance and throughput far exceeding what is needed. This rarely discussed practice of overprovisioning networks wastes money that could be better spent elsewhere.

Because networks typically last three to seven years, and because upgrades can be complex, disruptive, and costly, network professionals should purchase and deploy more network resources—slightly more than is needed over the entire network lifecycle.

Network configuration and capacity planning

Designing an enterprise network requires some research, buy-in from key business leaders, and following these steps to avoid overprovisioning.

Network capacity planning techniques include the following 4 steps:

• Review network baseline
• Review IT roadmap
• Understanding Network Hardware Limitations
• Identify business pivots

1. Review network baseline

When an enterprise plans to upgrade an existing network, the network capacity planning process should be initiated. Network professionals should review network monitoring tools using traditional Simple Network Management Protocol (SNMP) or modern network analytics platforms such as AI for IT operations (AIOps).

These tools monitor network component CPU, memory, and usage levels and graph network activity over time. They contain rich historical network usage and performance data that can serve as the basis for network capacity decisions.

If historical data is available (covering several months or even years), network architects can calculate the average growth in network usage and performance over time. The network team can use this information to predict future performance needs of the network.

Network professionals should also use historical information to review network bandwidth, especially at the Internet and WAN edge, to gauge whether throughput performance is reaching a point where it will hinder business operations.

Network professionals should also use this time to explore other Internet and WAN connectivity options. Many emerging technologies are available at reasonable price points (such as 5G), and, in many cases, multi-year contracts for connectivity services come with discounted prices. It is best to calculate the throughput required today and in the months and years ahead.

2. Review IT roadmap

While historical data is useful, teams should also consider future technology projects and their impact on network performance requirements. Common IT projects such as cloud migrations, IoT deployments, and big data analytics can cause dramatic changes in network throughput requirements, increasing, decreasing, or changing the flow of data throughout a company’s network.

For example, if the IT roadmap shows that applications and data currently managed on-premises will eventually move to the public cloud, then client and server data flows will change. These data flows will no longer be routed to the local data center. Instead, they will access public cloud services over the public Internet or direct WAN links.

This roadmap change will significantly alter the performance and throughput requirements of campus routers and switches. This means that as the IT infrastructure changes, the locations where teams provision network resources may also change.

3. Understand network hardware limitations

One way to understand hardware and software limitations, including maximum network throughput, is to refer to the network vendor's data sheet, which outlines all features, limitations, and upgrade possibilities.

For example, a chassis-based network switch can often have its core processor upgraded over time to increase backplane throughput. However, the chassis itself has an absolute maximum throughput it can handle, regardless of processor upgrades. Network professionals should understand these limitations to make the most cost-effective decision when upgrades are needed.

Likewise, switch stacks have become a popular option for the access and distribution layers of enterprise networks. However, unlike chassis-based switch hardware, when using a stack, the backplane capacity is permanent and cannot be upgraded. Network architects should keep in mind that when it is necessary to add additional switch hardware to the stack, each added switch will consume more throughput and eventually the limits of the stack backplane will be reached.

4. Identify business pivots

The fourth and often most difficult part to review when doing network capacity planning is to gauge the stability of the business. Network professionals should align network management strategies with the needs of their business. Ideally, if the business strategy is already determined, it means that network requirements will not change. In this case, the team should not allocate too many resources.

On the other hand, if the business strategy is likely to change, this creates resource allocation risk during the network capacity planning process. Pivots in network strategy may require more or less network resources. Therefore, business leaders need to determine how much over-provisioning risk they can take. They need to anticipate unforeseen needs, or they need to risk wasting resources - if the business strategy never changes.

This is where a what-if analysis comes in. You need to determine the likelihood of change and perform a cost-benefit analysis for each scenario as it relates to the network.

Weighing the costs of configuration and capacity planning

Before beginning this process, network teams should anticipate the costs of researching and planning for future network configuration and capacity. While inherent knowledge of business needs and future outcomes is an important component of network provisioning and capacity planning, network visibility tools make this task easier and less time-consuming.

Of course, network visibility tools also cost money and time to purchase and install. However, the good news is that the cost required to set up monitoring and analysis tools such as SNMP, AIOps, and NetFlow analyzers is worth the investment. In addition to monitoring, these tools can also troubleshoot network outages and performance issues. Most enterprises are willing to deploy these tools and use them for a variety of purposes, including network provisioning and capacity planning.