MetricSplit › Network capacity planning
Network capacity planning from your own flow data
Capacity planning is deciding, before the renewal or the complaint, which circuits are the right size, which are too small and which are too big. MetricSplit bases that decision on how full each WAN circuit runs at its busiest business-hours moments, in each direction, and on what the traffic actually is.
Four questions for every circuit
- How full does it run when it matters? The 95th percentile of 5-minute readings in business hours over 7 days, per direction. Averages hide the busy hour; a single peak overstates it.
- Is there room elsewhere at the same site? If the other circuit has room, rebalancing is the fix, and no purchase is needed.
- What is filling it? If non-business traffic takes enough room, limiting it can bring the circuit back under the line. MetricSplit shows how much room that would free.
- Could the site survive losing a circuit? For every site with two circuits, MetricSplit checks whether the remaining one could carry the whole site at its busiest moment. A site can be fine day to day and still not survive a failure; that is a separate decision.
The planning lines
| How full at its busiest | State | What it means |
|---|---|---|
| Over 85% | Needs action | Rebalance, restrict or upgrade now. |
| 60 to 85% | Approaching | Not urgent. Enter the next plan's price so the decision is ready. |
| Under 60% | Healthy | Room to spare. |
| Under 1% | Almost unused | Check the flow export, then price a smaller plan. |
An upgrade is recommended only when rebalancing and limiting apps can't bring the circuit under 85%, or when even a rebalanced site would still run above 60%. Verdicts are marked provisional until a circuit has 30 days of data.
Questions about network capacity planning
How do you calculate the bandwidth a site needs?
Measure what the site uses at its busiest business-hours moments, in each direction, over at least a week, and compare it with the circuit's capacity. Add the room the site needs to survive a circuit failure if it has two circuits. Averages over a day understate the need.
When should we upgrade a WAN circuit?
When it runs above 85% at its busiest moments and neither moving traffic to another circuit nor limiting non-business applications can bring it under that line.
How much data does capacity planning need?
A week of 5-minute readings gives a first, provisional answer. MetricSplit marks verdicts provisional until a circuit has 30 days of data.
Plan capacity on your own traffic
Flow records only, never in your traffic path. First findings arrive within days.