Network capacity planning tutorial (1)

What is Network Capacity Planning?

Networks evolve with a business. Whether you are planning a new LAN or maintaining an existing one, you need to model the data capacity requirements on the business’s needs. So, your starting point for network capacity planning is to document your existing resources, the networks current performance, and assess potential changes in demand.

If you currently document your network manually, you will need to start off by finding a network management tool to map the network and gather statistics on its performance.

We get into detail below on tools that will also assist you during the capacity planning task, but if you only have time for a quick glance, here’s our list of the best tools for monitoring current network performance:

  1. SolarWinds Network Bandwidth Analyzer Pack (FREE TRIAL) A bundle that includes the3SolarWinds Network Performance Monitor and the SolarWinds NetFlow Traffic Analyzer. Both tools run on Windows Server.
  2. SolarWinds Flow Tool Bundle (FREE TOOL BUNDLE) Free gift of the network tools from SolarWinds. These interact with Cisco routers.
  3. Paessler PRTG Network Monitor All-in-one monitoring package that covers networks servers, and applications. Installs on Windows Server.
  4. ManageEngine OpManager Plus Network device monitoring and traffic analysis in one bundle. Runs on Windows Server and Linux.
  5. Nagios XI Extendible network monitoring tool with a large and active user community. Runs on Linux.
  6. WhatsUp Gold with Network Traffic Analysis Add-on WhatsUp Gold is a network performance monitor that runs on Windows Server. Extend it with the Network Traffic Analysis add-on for capacity planning.

Planning requirements

The basic outline of capacity planning tasks is very straightforward. You just need to work out the following three factors:

  1. Current system potential capacity
  2. Current capacity utilization
  3. Bandwidth demand of new equipment/software

If you currently run a network, you may scoff at the simplicity of that outline. However, when performing capacity planning, it really does pay to keep things as simple as possible. In the baseline phase, you need to take into account the load on the network links and equipment that will be needed to support the new requirement. For example, if you are adding on 20 new user endpoints to the network, the segment that will connect those new nodes together and links that will carry traffic between those terminals and the servers that hold the storage and software that those users are expected to use are key. Your firewall and load balancer capacity is not relevant in this scenario.

So, capacity planning only needs to concern those resources that will be directly involved in serving the new requirement. You will be expected to add on new applications or equipment throughout your career managing your company’s network. Therefore, it is better to get a baseline for the whole system upfront, so that you are ready to implement any new requirement that the business comes up with. Those system statuses need to be updated regularly so that future capacity planning exercises aren’t based on out-of-date network metrics.

Establishing a baseline

You will need to take into account the following factors when gathering information about your current system:

  1. Network equipment
  2. End-user equipment
  3. On-premises servers
  4. Offsite servers
  5. Outsourced services
  6. Existing applications
  7. Subnets
  8. Remote access requirements
  9. VM demands
  10. External demand

Getting your baseline information involves measuring the existing network’s performance. This involves tracking data from both your network devices and your link capacity at the moment. Understanding which applications are delivered to which users is also a benefit because this can help you re-organize subnetworks to reduce pressure on trunk links. You can also reorganize scheduled tasks to reduce demands on important links and free up bandwidth for user-facing applications during business hours.

Planning for New Networks

Creating a network from scratch to support a fully-operational new business with no historic network performance is a tough job. Fortunately, it is also very rare. No business starts up fully formed. New businesses need to perform market research, run trials of products and services and assemble a team. So you will have a period when you can try your new network and check on the performance of each application and business service as you test it on the server. So, you never really will be required to create a new network that will be live on day one. Capacity planning is a recursive process that takes place as the business sets up.

Monitoring tools

Data gathering on networks is a complicated task that requires views on a wide range of information types that originate from a large number of sources. It is impossible to keep track of all the variables that can impact network performance without an automated monitoring tool. So, during your baselining task, you need to use an efficient monitoring suite to gather all of the information that establishes an acceptable level of service.

Logging equipment

Your first task, when establishing a baseline, is to create an inventory of all of your equipment. For network capacity planning you need to focus on your network devices, such as switches and bridges. For later phases in the capacity planning exercise, you will also need to list your end user devices and servers. If you have wifi routers in your network, you will also need to record the data throughput rate of each of them. If you use Software-as-a-Service online (SaaS) or employ cloud storage, you need to include those offsite resources as well.

Some network monitoring tools are able to cover entire WANs, so if you want to monitor many sites as an integrated network, you should be sure to choose a monitor that has multi-site capabilities.

You specifically need to know the total throughput capacity of each piece of network equipment. You should already know the bandwidth capacity of your cable type. It is not unusual for networks to include a mix of cable types. The upstream and downstream bandwidth availability of your internet service and the capacity of interfaces to external networks should also be logged. The throughput capacity of your firewalls, gateways, load balancers, and proxy servers also needs to be recorded.

With this data gathering phase, you fulfill the first information requirement of your capacity planning exercise, which is the potential maximum capacity of your network.

Map the network

Getting a visual representation of the network is very important. You may have a good equipment inventory tool that allows you to sort data and focus on each piece of equipment. However, there is nothing like a map to enable you to see instantly which switches are serving more links than the others. A visual representation also makes it easier to see how many links a typical conversation has to cross. The network mapping tool that you use should be able to display capacity utilization through color coding so you can spot congestion instantly.

If your business is web-based, your network traffic analyzer should specialize in tracking demand into your network from external sources. If you rely heavily on cloud-based services, your monitor should be able to track connections to those remote servers. Similarly, your bandwidth analyzer should be able to monitor internet links between sites if you run a WAN.

Gather capacity usage data over time

When you monitor your network, you will get to see which hours of the day, and which days of the month experience peak traffic loads, and when traffic levels are subdued. During regular operations, you should be able to schedule administrative tasks to run outside of business hours in order to avoid competing with user traffic at peak times. So, before you add on new services, you should have your network working efficiently. When your capacity planning study begins, you need to track the capacity utilization over several working days so that you can get a view of your peak utilizations over the resources that will serve the new demand.

Get a record of high, low, and average throughput on the links and equipment that are due to work for the new requirements. You need to know whether the peak demand is close to typical or only occurs on a limited period on any given day.

You also need to measure the packet loss rate. You should record this figure as a percentage. See whether the packet loss rate increases during high demand periods. Apply the packet loss rate to your bandwidth availability by deducting the calculated percentage from your figure of available bandwidth. Alternatively, you can choose to add that percentage to the new bandwidth requirements.

Now you have the second input to your capacity planning. That is, the current data throughput of your network.

Estimate new bandwidth demand

Getting a figure for bandwidth requirements for any new software that you intend to install is pretty easy. The providers of most software that is to be delivered across a network give information on the bandwidth that their software uses in its Systems Requirements statement. In some cases, this figure is expressed as a range. If that range is wide, the information won’t be much help to you. Usually, the bandwidth requirements express the throughput expected to serve one user, so if you are buying several licenses, you should plan to have the extra capacity to cater to the given bandwidth requirement multiplied by the number of licenses.

If the software company does not provide a bandwidth requirement, ask for a trial copy and run it over the network as a single instance to log its throughput. The commissioning manager in your company who requested the installation of this software will probably require an assessment period. That run through will enable you to gather bandwidth requirement data.

Your monitoring tool should enable you to track the traffic of a specific piece of software. If it doesn’t, you should be able to track protocol activity. If your new software is replacing a package that is already in use on the network, both the new and old software will probably use the same protocol or port number. In that case, you would need to record that traffic outside of normal business hours so that you don’t confuse the bandwidth used by both systems. Another option is to employ QoS tagging so that you can run the new software test while the old system is still in operation. Once you have a standard traffic pattern for one user, multiply that figure by the maximum number of users that will be allowed to use that software simultaneously.

If your capacity planning exercise is examining the effects of adding on new user devices to the network, record the amount of traffic to and from an existing node that serves the same work roles that will use the new devices. Multiply those traffic figures by the number of endpoints that you expect to add to the network.

The figures you acquire with this phase of the study give you the third element of data that the capacity planning task requires — new bandwidth demand.

Basic network capacity planning

Your network performance monitor and your bandwidth analyzer should have provided you with the input data for your capacity planning enquiry. Hopefully, you also have a network administration tool that supports analysis functions.

The capacity test is a simple exercise of adding the new bandwidth requirements to your current peak and average bandwidth usage. Next, look at the maximum capacity of each piece of equipment and each network link that the traffic will pass through. You should know this route thanks to your network map. Look to the network element that has the lowest capacity. Don’t forget to adjust your figures for the packet loss rate. If your new demand is below that level, you are all clear.

If your tightest bottleneck can’t cope with the new traffic, look at other elements in the path in order of increasing capacity to see which of those also could not cope with the new traffic.

You may find that you have more than one element that needs to be replaced in order to keep the new service operating at an acceptable speed.

Capacity refinements

The discovery that your network cannot cope with the new capacity demand means that you need to make some decisions and you will probably need to include others in your decision making. You will need to present options to other managers in the business and so a network administration tool that has reporting functions will really help you in this task.

In any infrastructure capacity decision you always have three options:

  1. Buy new resources.
  2. Reorganize the network to add capacity to the path of this requirement.
  3. Cancel the new acquisition.

The initial capacity test showed you a list of equipment that could not cope with extra bandwidth demand. Get quotes for replacements of each element with new equipment that has greater capacity. This will give you the cost of the first option on the above list: buying new resources. One advantage is that you don’t have to throw your existing equipment away. It can be moved to other parts of the network to provide spare capacity that will cater to future extra demand. Every network administrator should plan for a continual increase in network bandwidth.

No-cost capacity options

You will need more information about your network in order to support this decision-making process. The no-cost option of reallocating underutilized resources is always going to be the choice of the board of directors, so you first need to investigate that possibility before raising their hopes. You can go in three directions to get the most out of your network:

  1. Physically move network equipment.
  2. Reallocate resources virtually.
  3. Implement traffic shaping.

All of these options require levels of analysis that cannot be achieved without network administration tools.

Reassign physical equipment

Option one on the no-cost options list would be nice, but you probably don’t have a spare switch on your network with links that carry almost no traffic. If you do, then you have probably overspent at some point in the past. The traffic throughput of all of your network devices shown on the network map will aid your decision making when looking for spare capacity. A printout of your network map, showing the capacity and utilization of all your links will add a visual element to your presentation when you need to include non-technical managers in the planning process.

Use your network administration tool’s analysis functions to log the maximum load on each switch and router. If there are two that serve less than half of their maximum capacity and one of them has enough spare sockets to take more cables, then you have the option of merging two segments and freeing up a switch. With that extra equipment, you can divide up the overloaded segment and double your capacity to those endpoints.

This is just one example of the steps you can take to physically expand the capacity on one part of your network at the expense of another in order to cater to new traffic demand. The monitoring capabilities and analytical functions of your network administration tool will get you through this complicated task.

Introduce virtualization

Virtual reallocation is possible if you have virtualization applications, such as Hyper-V or VMWare. Sharing a server among endpoints not only reduces hardware costs, but it can also reduce network traffic. When users log in to the processor remotely, much of the interfacing between applications and storage can be limited to one server or run over one link. This generates less traffic than messages passing back and forth across the whole network between user endpoints and servers.

Virtualization is complicated and difficult to assess, so you need a tool that is dedicated to monitoring the traffic that these systems create. If you don’t already implement virtualization, it is probably better to put off this option for consideration at a later date when you have less pressure on your time.

Implement traffic shaping

If you don’t have spare capacity anywhere on your network and the new requirement is going to overload part of your system, you could propose traffic shaping. The debate between buying new equipment and traffic shaping is one of the main reasons that you need to get senior staff involved in the decision over how to cater to the new requirement. Being able to distill network capacity information into easily-digestible graphs and summaries will ease the process of trade-off. Someone is not going to be happy about the results of this exercise.

If you tracked your network throughput over time and stored that data, your analysis tool will be able to replay that traffic and segment it by protocol and endpoints. So, you can identify which traffic generating tasks can be moved to overnight processing in order to free up capacity. If you have already used up that option to squeeze extra value out of your network budget, then you still have one more traffic shaping option: prioritization. Try queuing algorithms, such as Class-based Quality of Service (CBQoS) to ensure that some traffic gets through faster than others.

Your capacity planning tool will help you see the effects of this move. However, it ultimately means that some users will get slower response times for the applications that they need to use interactively. You should be able to print off reports from your planning tool in order to illustrate the effects of this policy.

Capacity planning decisions

If the existing services cannot be slowed down to create bandwidth space for the new requirement, your management team will be faced with the decision of spending money to buy new infrastructure or canceling the new project. These are decisions that are not within the realm of the network administrator. You should prepare all of the information needed to support the decision and provide stakeholders with illustrated scenarios. The reports from your monitoring tool and snapshots generated out of your capacity planning software will enable you to furnish this supporting documentation.

Capacity planning tools

You need a proficient capacity planning tool in order to support the decision makers in your business when a new project is proposed. That tool needs the following attributes:

  • Integration with network monitoring software
  • QoS capabilities
  • Time-based analysis
  • Link visibility and end-to-end connection analysis
  • Traffic replays
  • Storage of historical data
  • Reporting capabilities
  • Data visualizations

The five monitoring tools proposed earlier in this guide all fulfill these requirements. Here are further details of each of these options.

1. SolarWinds Network Bandwidth Analyzer Pack (FREE TRIAL)

SolarWinds Network Performance Monitor

SolarWinds produces the industry-leading Network Performance Monitor. This tool tracks the health of network devices. When you look into network capacity planning, you also need the SolarWinds NetFlow Traffic Analyzer, which examines network link performance. You can get these two tools together in the Network Bandwidth Analyzer Pack.

The Network Performance Monitor starts off with a network scan. This gives your baseline of network equipment capacity. The monitor runs continuously and tracks the status of network devices. This includes information on the throughput of data. Each device agent will raise an alert if the demands on that piece of equipment approach its full capacity. This monitoring continues and logs when queuing occurs – that indicates that the device has become overloaded. So, after running the Network Performance Monitor for a few days, you will have all of the preliminary baseline information that you need to perform network capacity planning.

The NetFlow Traffic Analyzer has a confusing name. NetFlow is the name of a network equipment reporting system designed by Cisco Systems. Other equipment manufacturers use NetFlow, but it is not a universal standard. So, you may be discouraged from buying this tool because you don’t want your equipment purchasing options to be limited to those devices that implement NetFlow. Don’t worry. The NetFlow Traffic Analyzer is also able to receive other network equipment messaging protocols. These include J-Flow from Juniper networks and NetStream, which is used by Huawei devices. Recognition of the manufacturer-neutral sFlow and IPFIX protocols are also built into the NetFlow Traffic Analyzer. This tool will report on the total capacity of each link in your network and also give you live reports on bandwidth usage. This information can be recorded for analysis.

The Network Performance Monitor and the NetFlow Traffic Analyzer are built on a common platform, so they can exchange data; there are some functions in the dashboard to which both modules contribute. The PerfStack analyzer is one of these. This enables you to build up a visual stack showing supporting services so that you can spot the source of network performance problems. This is an example of the visual tools that SolarWinds provides with this software pack. Another great feature is the network map, which can be customized and is based on live data. The network map shows traffic capacity utilization and makes it easy to see network traffic throughputs at a glance. A wireless heat map shows the signal footprints of your wifi routers, which you can show on the actual layout of your offices if you upload floor plans.

The NetFlow Traffic Analyzer is able to track CBQoS, so you can isolate any traffic when you are trying new software and network layouts. This feature is also useful for VLAN implementations that run your voice traffic over your data network. If you are looking for spare capacity, identifying types of traffic gives you traffic-shaping options.

Other traffic attributes that the NetFlow Traffic Analyzer gives you include the ability to identify traffic by protocol or port number. Both the Network Performance Monitor and the NetFlow Traffic Analyzer can track the capacity utilization of wireless networks. The combo pack of tools can also reach out across the internet to cloud services and remote sites, logging all of the offsite services and equipment that your business uses.

Both of these tools include great visualizations in the dashboard. These include charts, graphs, histograms and dials, all of which are color-coded to show you statuses at a glance. All traffic data is shown live in the dashboard, but it can also be saved for analysis. The package ships with standard reports that will cover just about all of your presentation needs, but the system also allows you to create your own customizable reports.

The SolarWinds Network Analyzer Pack installs on Windows Server environments. It isn’t free. However, you can get the pack on a 30-day free trial.

SolarWinds Network Analyzer Pack Download 30 day FREE Trial at


2. SolarWinds Flow Tool Bundle (FREE TOOL BUNDLE)

SolarWinds NetFlow Tool Bundle

The SolarWinds Flow Tool Bundle is a free set of tools for testing network traffic volumes. The tool works with NetFlow v5 messaging through Cisco routers. NetFlow was invented by Cisco Systems to aid in the analysis of traffic patterns on networks. It can capture IP headers and send them to a collector for viewing and storage and it can also produce packet summary data on aggregated packet traffic.

The great advantage of the NetFlow system is that it doesn’t dump out all of the contents of the packets traveling around the system, so there is no danger that network admin staff will break the confidentiality of the company’s data while analyzing traffic flows. One downside of leaving NetFlow on all the time is that it will create extra traffic on the network and also generate large volumes of data that will need to be stored.

One of the elements of the Flow Tool Bundle helps you manage the activation of NetFlow on your routers. The other two tools in the pack aid network testing. These three utilities are:

  • NetFlow Configurator
  • NetFlow Replicator
  • NetFlow Generator

The NetFlow Configurator acts as an interface to your Cisco routers so that you can turn NetFlow on and off easily and tell the routers where to send the Netflow data. This saves you from having to visit each router, log in to it and click down through the menu to find the NetFlow function. So, the NetFlow Configurator is a very simple tool, but it will save you a lot of time.

The NetFlow Replicator lets you replay traffic data through your network. This will help you to see what happened on the network while you were occupied with other tasks. This is a great way to see errors, bottlenecks and traffic slowdowns. If the problem was caused by a temporary fault on a network device, those traffic challenges won’t arise during the rerun. If the problems were caused by a traffic surge. You will be able to see it and take action accordingly.

The NetFlow Generator will create fake traffic for you so that you can see how your current network infrastructure will cope with increased load. Although you should be able to calculate this on paper by adding expected increases in volume to your current throughput, actually seeing those traffic patterns live will make sure that you haven’t overlooked any part of the system. This is also a good exercise to test the capacity and efficiency of your load balancers, firewall, and network monitoring software to make sure that they can all cope with planned expansions in demand.

The three utilities on the Flow Tool Bundle will give you a free method to plan your network capacity and analyze any shortcoming in your current set up.

SolarWinds Flow Tool Bundle Download 100% FREE Tool Bundle


3. Paessler PRTG Network Monitor (FREE TRIAL)

Paessler PRTG network map

Paessler produces an all-in-one solution to infrastructure monitoring and called it PRTG. This tool includes both network device monitors and traffic analysis as well as server monitoring.

You can choose to install PRTG on premises or use it as a cloud service. Even if you go for the online version, you will have to install some software on one of your servers. This is a data collection agent and it runs on Windows Server, as does the full package if you opt for the on-site version.

The first task of PRTG after you activate it is to scan your network and create a device inventory. It will also create a network map from the information it gathers on switches and routers. The maps that PRTG generate are impressive. You will get a straightforward view of devices and the connections between them and PRTG offers some more sophisticated mapping options as well. If you have a WAN you can get your devices and links plotted on a map of the world which has a zoom option. PRTG includes a distinctive sunburst map format, which shows each hardware element, service, and application that support each other. A design tool lets you create your own custom maps.

The network traffic analysis section of PRTG uses Ping to detect the packet loss rate on each of the links on your network. The data flows detected by PRTG can be filtered by application, endpoint addresses, or protocol/port number. This tracking extends out over the internet to cover links to remote sites and Cloud services. The network tracking also covers any wifi systems that you operate in your offices.

Traffic flows are registered through the use of NetFlow, IPFIX, jFlow, and sFlow. PRTG also includes a packet sniffer to gather sample data for analysis. The SNMP capabilities of the monitor gets bandwidth capacity feedback from each network device and you can set alerts that will notify you when each piece of equipment is approaching full capacity.

PRTG is capable of monitoring VLAN traffic, particularly VoIP traffic passing over the data network. The monitor can log your traffic flows that are tagged for the QoS, CBQoS, and IP SLA standards.

The dashboard of PRTG includes charts and dials to help you see statuses quickly. Alert conditions show up in red, which makes them easy to spot. Alerts can be sent to you by email notification or SMS message. You can also decide which team member receives alerts for specific data sources or alert types. It is also possible to customize the dashboard to give different team members access to different functions. The reporting tool provides a good source of presentation material when you are called upon to explain the capacity of the system and its ability to take on new requirements.

The PRTG system ships with a large number of “sensors.” Each condition on a network is monitored by one of these sensors. For example, the package includes a Ping sensor, a packet sniffing sensor and a NetFlow sensor. You don’t have to turn all of the sensors on, so the PRTG system can be tailored to cover just one aspect of your infrastructure. The service is charged according to the number of sensors that you activate. PRTG is free if you only need to monitor up to 100 sensors. You can get a 30-day free trial of PRTG with unlimited sensors.

Paessler PRTG Network Monitor Download FREE 30 day Trial at


4. ManageEngine OpManager Plus

OpManager Network Map

OpManager Plus combines a network device monitor and a bandwidth analyzer with a server and application monitor, an IP address management system, a switch port manager, and a configuration manager. This is a very comprehensive infrastructure administration tool, but it is particularly the device monitor and the bandwidth analyzer modules that will assist you with your network capacity planning activities.

The network monitor module is available to buy as a separate module, called OpManager and you can also buy the NetFlow Analyzer separately. If you buy these two modules, they will integrate together because they were built on a common platform that facilitates data interchange. All ManageEngine products run on Windows or Linux.

The network device monitor module includes a discovery function that will map your entire network, recording the statuses of each device. This utility is able to reach over the internet to log Cloud-based servers and the remote sites of a WAN. The discovery process also covers wireless network equipment and the connections between hardware and services that form virtualizations.

The discovery process keeps running throughout the service life of OpManager Plus, giving live updates on statuses. The monitor uses the SNMP protocol, which allows device agents to send alerts to the central controller. Alert conditions include warnings when a piece of network equipment is approaching its bandwidth capacity, so you can avert device overloading, or implement queuing. All data gathered by the network device monitor and the bandwidth analyzer can be stored for use in analysis and capacity planning.

The device inventory forms the basis of a network mapping module, which plots all of your switches, routers and wireless APs automatically, showing the links between them. You can filter the map to show just switches, or just routers and you can also get your WAN devices plotted on a world map. That map includes a zoom option so you can examine all of the devices on an individual site. You can choose to have each device label show the hostname, MAC address, or network IP address. Other mapping options include a server cabinet view and a server room layout plan.

SNMP gives device bandwidth utilization data and the bandwidth analyzing module of OpManager Plus gives greater detail on traffic flows across each link on your network. The analyzer can collect network traffic statistics reported by the NetFlow, IPFIX, jFlow, NetStream, sFlow, cFlow, AppFlow, and FNF device messaging systems. The metrics that arise from these messages are shown live on screen and can also be stored for analysis and capacity planning. The bandwidth utilization data can also be used to support alerts that look for capacity exhaustion.

Data is shown in the dashboard both as lists and as graphical elements, such as dials, graphs, and charts. The title band of the dashboard screen can be used as a summary strip, showing small icons of color-coded graphs that show live data. Each icon acts as a link to a detail screen for the metric that it represents. The dashboard can be customized and you can set up user roles and accounts, giving limited controls and data views to different team members. The dashboard can also be accessed remotely from mobile devices.

Both the charts and maps as well as data lists can be printed out as reports. The live data and stored historical records can be filtered and sorted to help your management and capacity planning activities. A Ping function will track the packet loss rate on each link of your network to help you adjust capacity data. You can also implement IP SLA in the monitor to measure performance metrics such as jitter, latency, Mean Opinion Score, and packet loss. The bandwidth analyzer will also report on round-trip time on connections to remote facilities. Data and map displays can be filtered by application or port number/protocol activity.

The analyzer integrates the Cisco Network Based Application Recognition (NBAR) methodology to segment traffic data. It is also capable of implementing and monitoring traffic shaping and VLAN tagging methods, including Access Control Lists (ACL) and Quality of Service (QoS). OpManager Plus is able to use Class-Based QoS to help you prioritize traffic through queuing policies.

A special Capacity Planning section in the dashboard gives you time-based bandwidth utilization graphs and supports your planning for natural traffic growth through predictive functions.  Capacity figures get collected around the clock and seven days a week, so you can examine out of hours activity to find periods suitable for processor-intensive batch jobs. These planning services include some great graphics to ease the capacity planning process.

ManageEngine offers all of its products on a 30-day free trial. You can use the standalone network device monitor, which is called OpManager, for free to monitor up to 10 devices.

5. Nagios XI


Nagios XI is an infrastructure management package that covers networks and servers. The processing engine of Nagios is an open source project. You can use it for free in the guise of Nagios Core. This free tool doesn’t have a very good interface however, and you won’t find much support for analysis and capacity planning in it. In order to get a better dashboard, you would either have to research other analysis tools that are compatible with Nagios or upgrade to the paid Nagios product, which is Nagios XI.

Nagios XI runs on RHEL and CentOS Linux. It isn’t available for Windows, but you could get it on a Windows environment by running it through a virtual machine (VM). The command center can communicate with devices running non-Linux operating systems and firmware and it can also monitor virtual environments. The monitor extends to remote locations, Cloud servers, and wifi systems.

Unlike the other network tools on this list, Nagios doesn’t use SNMP to monitor network devices. It has its own proprietary method built into the Nagios Core engine, which communicates with devices to gather status reports. The metrics that are gathered regularly by the monitor appear as live data in the dashboard and you can also opt to store data for analysis later. The Nagios community is a forum where you can pose questions and get tips from other Nagios users. Many users produce their own modules for Nagios because the system can be extended by plug-ins. There is an SNMP plug-in available from the community if you want to stick to this industry standard monitoring method rather than the default Nagios monitoring routines.

The types of data that you can monitor with Nagios include device capacity, bandwidth usage over time, and packet loss on each link. The interface includes a capacity trend graph that shows you how data throughputs and system usage has expanded over time, continuing on to predictions of future capacity needs.

Nagios XI maintains a device inventory and presents you with a network map, which is drawn automatically. The map and all data can be set to replay traffic data during your capacity planning exercise. This enables you to see the network’s capacity performance over several days at one time.

The dashboard is completely customizable. When you buy Nagios XI you get a package of widgets. You pick a widget and place it on the dashboard canvas, thus producing your own layout that features the metrics that are important to you. You can create several versions of the dashboard and allocate them to user roles. You are also able to set up user accounts for access to the Nagios system and you allocate a role to each account. This enables you to create different views and controls for the network and allocate those dashboards to different team members.

Nagios XI includes some pre-written report formats, but you can also create your own layouts in a reporting tool that is included in the package. The graphs and other data visualizations, such as the network plan, can all be printed out to provide you with presentation material to support collaborative decision making.

You can try out Nagios XI before you invest any of your company’s money in the system by taking up a 60-day free trial. The Nagios XI is available in two levels of service. The pre-written capacity planning capabilities are only included with the higher service level. However, you could create your own capacity planning reports or look for free planning add-ons from the community if you opt for the cheaper version of the tool.

6. WhatsUp Gold with Network Traffic Analysis add-on

WhatsUp Gold is a network monitor that focuses on the health of network equipment. The company that produces WhatsUp Gold, Ipswitch, created a series of add-on modules that integrate into its main product. One of these, the Network Traffic Analysis Add-on will give you data about traffic flow across network links. Both of these software packages run on Windows Server.

When you install WhatsUp Gold it will search the network and record all of the network devices. The system builds up an inventory of your network devices, including their bandwidth capacity. The software will automatically draw up a network map from this information.

The WhatsUp Gold monitor continues to query all devices to get an update on their statuses. This includes the amount of throughput that each device is handling. The information derived from these queries gets updated in the equipment inventory and also gets reflected in the network map. An extra benefit of this process is that you don’t have to update the inventory or redraw the map if you add or remove devices. Each piece of equipment in the network map is shown as a round icon. The edge of the disk is color-coded to show the health of the device that it represents. If the device approaches its full capacity, that circle will turn red.

The links drawn on the network map are also color-coded. Those statuses are gathered by the Network Traffic Analysis add-on. This module receives traffic metrics from network devices via a number of messaging protocols. These are NetFlow, NetFlow Lite, IPFIX, jFlow, sFlow, and QUIC.

The main WhatsUp Gold package and the Network Traffic Analysis add-on will provide you with all of the information on existing traffic capacity and utilization for your capacity planning exercise. If you need to run a test of the new applications that you want to add to the network, you can use the CBQoS and NBAR capabilities of the Network Traffic Analysis module to track its traffic patterns.

For analysis and capacity planning, the traffic monitor presents data that can be sorted, filtered, and aggregated to show you the capacity of each link and network device. These traffic patterns can be derived from live data as well as historical data. This shows the peak traffic events on each network element. You can apply analysis to a group of devices, which enables you to focus just on the areas of the network that will be affected by new projects.

The WhatsUp Gold system ships with standard reports that show traffic by a range of different attributes. These reports can show a league table of the top sources of traffic by software package, application, protocol, or IP address. Data in the dashboard is represented in lists and also in graphical content such as line graphs, charts, and dials. The data presentation features of this software will help you explain the network status to non-technical staff. You can get a 30-day free trial of WhatsUp Gold and the Network Traffic Analysis add-on to put them through their paces.

Other capacity issues

When you intend to expand the services of your network, there are peripheral issues to consider. You may have room on your server for new software, but will your server’s CPU be able to handle all of the additional demand for processing? Will your server’s network card still be able to send out and receive in all of the traffic that your existing programs generate and still have bandwidth for these extra requirements?

If you interface heavily with the internet, your firewalls, load balancers, proxy servers, and DDoS mitigation capacity may need to be upgraded. Does your internet service agreement have throughput limits? Will your service provider be able to cope with the extra internet traffic that your system changes might generate?

The network does not operate in isolation, so there will be other hardware considerations to take into account when you plan to expand. In each case, measuring current resource usage, recording resource capacity limits, and estimating new capacity requirements will all have to be applied in a capacity planning phase before you can start the implementation of your new project.

Network capacity planning

No business is static and hopefully, the constant change that your organization experiences is all generated by expansion. You need to allow for growth in traffic which will occur naturally as the business grows even if your users don’t demand any new software or hardware. As a network administrator, you need to keep an eye on live data showing traffic volumes because they will rise and the alerts that your system raises to notify you of approaching capacity exhaustion will occur more and more frequently until you add on new resources.

Resource monitoring and capacity planning are two activities that go hand-in-hand. There are many reasons why you may need to run a capacity planning exercise. However, one constant is that you will always need to have very detailed information on your network’s current activities before you can start to plan for the future.

Do you use network monitoring tools that give you capacity planning support? Which is your favorite tool? Have you tried and rejected other network planning software that isn’t on our list? Do you recommend any of the systems that we have featured in this guide? Let us know about your experience by leaving a message in the Comments section below.

Image:  Information Technology Industry 4 from Max Pixel. Public domain