Network Capacity Planning

Today’s network managers have to balance two conflicting demands: the desire for increased speed of response and optimal end user performance, and the need to reduce operational costs. Traffic – business or otherwise – tends to expand to fill the available network bandwidth capacity, degrading performance across the most congested links. Network managers cannot simply throw bandwidth at the network capacity problem, but have to demonstrate that a link is experiencing congestion for a significant amount of time due to legitimate business usage before they can add additional network capacity. Break away from the traditional approach to capacity planning by understanding the new principles for effective network capacity planning.

 

Why effective network capacity planning is becoming critical

In any distributed organization, the cost of network connectivity is always difficult to quantify. Traffic on the network tends to expand to fill the available bandwidth, whether or not that traffic is crucial to the business. Usage of business-critical applications is also difficult to measure. It may be within expected parameters for 90% of the time, but no business wants to experience degraded performance for the remaining 10%.

Network performance requirements put constant pressure on IT to increase network capacity in order to provide an effective service to the business, while cost management requires that this is limited, or even reduced. So, how can an IT organization manage these conflicting pressures?

Technical Challenges With Network Capacity Planning

  • To identify a link that requires additional bandwidth capacity, you must demonstrate that it is experiencing congestion for a significant amount of time.
  • It can be costly, time-consuming (sometimes, depending on the tools used, even impossible) to correctly represent congestion over long time periods.
  • Congestion must be caused by legitimate business usage, not recreational or rogue usage (“other” traffic): bandwidth spending is the final resort, removing “other” traffic from the network comes as a much earlier option.

Common Approaches to Network Capacity Planning

  • Long-range views of average utilization: this will show a long-term trend of utilization, but the long-term view will average out those spikes of high utilization, thus hiding the problem.
  • Peak utilization, e.g. showing the busiest minute for each day in a month: This shows what days had a busy minute, but doesn’t give insight into the amount of time during which time a link is congested.
  • Traffic totals: easy to show all links on a single view, showing the links with most traffic and even periodic trends to show month-by-month usage. However, it does not give any indication of congestion except in extreme cases.

With NETSCOUT's TruView, you can monitor your WAN utilization across your entire network for capacity planning, even if you don't have NetFlow exporting from every site.

It has been difficult to get a long term understanding of interface utilization while maintaining accuracy and having an understanding of how that utilization maps to business application usage. NETSCOUT's solution for capacity planning allows you to make smart decisions on where you have the most and least room for growth.

The TruView Solution – Simple, Accurate, Effective Network Capacity Planning

Use the Capacity Overview to identify which links have been over-utilized, and for how much time. Those links that were over 80% utilized for more than a threshold timeframe are highlighted with a red icon.

  • Using a Burst-style view, TruView for network capacity planning displays the amount of time for which utilization is within each utilization band, from <30%, 30–60%. 60–80% and >80%. This clearly and simply shows what links spent the most amount of time in a congested state (<80%).
  • Based on 1-minute measurements, detail of congestion is never lost for views of months, weeks or even a year.
  • “Follow the red” to see the most congested links.
  • Reverse the ordering to see those links that were never utilized over 30% and thus may be downgraded.
  • Include a Business Hour filter to examine only daytime usage, eliminating interference from nightly backup and update jobs.
  • For those links which are not over-utilized, use >60% levels to help build long-range budget estimates.

View the utilization levels over time on the Capacity Detail page, and identify who and what made the links busy with Application and Host breakdowns.

  • Use a single-link view to easily determine if congestion is caused by valid business usage or unauthorized / recreational use.
  • SNMP and NetFlow data are combined to show when a link is busy, how busy it is, but also why it’s busy.
  • Burst detail broken out to a time trend to show if usage is stable, erratic or growing.
  • Simple-to-understand view, can be used as part of a business case for increased bandwidth spending.

Network Capacity Planning is one of several functions your organization can perform with TruView, a Network and Application Performance Monitoring system.