The short version
Businesses usually size internet by picking a speed that sounds adequate. That produces two failure modes: paying for capacity that is never used, or discovering at 11am on a busy Tuesday that voice and video fall apart while a speed test still reports fine.
A better approach is to work from what runs at the same time, pay attention to upload, and leave headroom.
| Activity | Constraint it creates |
|---|---|
| Cloud phone calls | Modest bandwidth, high sensitivity to jitter and loss |
| Video meetings | Sustained upload as well as download |
| Cloud file sync and backup | Heavy upload, often unnoticed |
| Hosted applications | Steady, latency-sensitive |
| Remote access to a site | Upload from the site’s perspective |
| Camera remote viewing | Upload from the site’s perspective |
| General browsing and email | Download, bursty, tolerant |
Count concurrent activity, not headcount
Headcount is a poor proxy. A ten-person business where everyone is on video calls to clients uses far more than a thirty-person warehouse operation where most staff are not at a screen.
Work through a realistic busy period and estimate:
- How many phone calls run at once
- How many video meetings run at once
- Whether large files move in or out during the day
- Whether backups run during business hours
- How many people access hosted applications continuously
- Whether anyone views cameras or accesses the site remotely
That last group is easy to miss and pushes upload, because from the site’s point of view the data is going out.
Upload is usually where it breaks
Most business services still advertise download prominently, but the things that fail first are the two-way ones.
Every participant in a call or video meeting is sending. Cloud backups push upstream continuously. File sharing to clients is upload. Remote camera viewing is upload. On a connection where upload is a fraction of download, that path fills long before anyone notices a download problem — which is exactly why the symptom presents as “the phones are bad” rather than “the internet is slow”.
If the business runs cloud phones, upload capacity should be the number driving the decision. Dropped calls on cloud phones covers what under-sizing looks like in practice.
Consistency beats headline speed
For voice and video, a smaller connection that behaves predictably outperforms a larger one that varies.
The measurements that matter are jitter, latency and packet loss under real load. A connection that speed-tests well at 7am tells you very little about how it behaves at 11am when everyone is working.
This is where connection type matters more than plan size. Services differ in how they handle contention at busy periods, and a business-grade service with stronger commitments may deliver a better experience than a faster plan on a contended service. NBN business fibre vs Enterprise Ethernet vs 5G covers the trade-offs.
Find the hidden consumers
Before upgrading, it is worth checking what is already consuming the connection. Common findings:
- Backups running during business hours rather than overnight
- A single workstation syncing a large dataset
- Guest Wi-Fi with no limits, carrying streaming traffic
- Software updates downloading to every device simultaneously
- A device stuck in a retry loop, consuming capacity while achieving nothing
Several of these are free to fix by rescheduling or applying limits. A business that upgrades without looking may pay monthly for capacity that a scheduling change would have released.
Leave headroom, and prioritise
Two design choices make a connection behave better than its size suggests.
Headroom. A connection running near capacity at peak has nothing left for an unusual day. Size for the busy case with room above it, not for the average.
Prioritisation. Marking voice traffic so it is sent ahead of bulk traffic means a backup job cannot degrade a call. Most congestion occurs in your own upload queue, so this is within your control regardless of the plan.
A practical sizing method
- List concurrent activity at a genuinely busy time
- Separate upload from download requirements
- Identify the critical services — usually voice, then hosted applications
- Check what already consumes capacity and reschedule what can be moved
- Add headroom above the peak
- Choose the connection type on consistency, not only speed
- Prioritise voice on the gateway
- Size the failover path for essential traffic, covered in business internet failover and redundancy
Helpful starting points
If phones and cloud applications are struggling, start with business internet and measure the connection under load before changing plans. If the local network may be the real constraint, Wi-Fi and network solutions covers switching and coverage. For a new site, size the service before ordering — see internet lead times for a new tenancy.