The most expensive mistake in corporate connectivity is buying a circuit sized for the average load rather than the peak, and the second most expensive is buying one sized for a peak that never happens.
Start with three numbers: concurrent users, the heaviest cloud application in daily use, and your month-end or payroll burst. Office productivity traffic is remarkably light — 200 kbps per user is generous for mail and documents. A single video call doubles it. A cloud ERP session with large attachments can multiply it fivefold.
Then add the things nobody counts. Backups to offsite storage that run at 2 AM can consume your entire circuit. Guest WiFi on a separate VLAN will consume whatever you let it. CCTV streaming offsite at 4 Mbps per camera adds up far faster than most finance teams expect.
Once you have a peak figure, apply a headroom factor of 30%. That is your dedicated bandwidth requirement. If the answer is 20 Mbps, buying 100 Mbps does not make your staff faster — it makes your invoice larger.
Where a second circuit earns its keep is redundancy, not speed. Two diverse paths, ideally from different carriers and different physical routes, protect against the fibre cut that no SLA can prevent. Diversity is the real value of a second link.
