Fibre Performance

How to improve your business internet speed on the fibre you already pay for

Most offices leave speed on the table long after the fibre is installed. The fixes are rarely a faster package; they are the router, the wiring, the traffic rules and a plan for power. Here is how to get every megabit you are paying for.

50%+upload as a share of download, minimum
20–30%speed headroom to buy for growth
≤5:1contention ratio on premium business lines
20–40 mina 1000 VA UPS keeps your router online

The short answer

How do I improve my business internet speed with fibre?

Match the package to your real usage with 20 to 30% headroom, then fix your own network: a business-grade router with quality-of-service, wired connections for fixed devices, and traffic rules that put VoIP and video first. Add a UPS and a failover line so a power dip does not take you offline.

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comfortable for a 10 to 50-user office
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per user each way keeps video calls smooth
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fault-response window a strong SLA promises
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rand buys a business-grade UPS for your router

A Neat South African Office Network Cabinet With A Business-Grade Router And Switch, Cabling Tidy And Labelled
Your fibre line is only as fast as the network behind it. Most speed problems live in the router and the wiring, not the ISP.

What fibre speed does your business actually need?

Buying more speed than you use is a waste; buying too little throttles every call. Size it to your team and applications, then add a growth buffer.

Most small businesses (1 to 10 users) run comfortably on 10 to 20 Mbps. Mid-sized operations (10 to 50 users) typically want 50 to 100 Mbps, and larger teams or those running video production, heavy cloud apps or big data transfers need 200 Mbps or more. South African fibre packages now span 2 Mbps to 1 Gbps, though what you can get depends on the network at your address.

The number most businesses get wrong is upload. Consumer packages are asymmetrical, fast down, slow up. But cloud backups, video conferencing and VoIP all lean on upload. Aim for upload at least 50% of your download, and closer to symmetrical if the budget allows. A team of five on video calls needs roughly 2 to 3 Mbps per person in each direction, plus headroom for everything else.

Bottom line: calculate your peak concurrent need, then buy 20 to 30% more. Growth and busy-hour spikes eat that buffer faster than you expect.

How to choose the right fibre package

Four dimensions decide whether a package performs: speed tier, contention ratio, data policy and the SLA. Price alone tells you almost nothing.

Contention ratio is the one most buyers never ask about. It measures how many users share the same upstream capacity. A 20:1 ratio means you share with 19 other businesses, and at peak hours your speed can sag. Premium business lines offer 5:1 or lower, and fibre-to-the-premises usually beats fibre-to-the-cabinet on contention.

Data policy still matters here despite fibre’s capacity. Some business packages are truly uncapped; others apply a fair-use threshold. If you back up large datasets, stream, or run video surveillance, an uncapped or unshaped business line is worth the small premium.

The SLA is your safety net: it defines guaranteed uptime (for example 99.5%), a fault-response window (often 4 hours) and sometimes credits when performance drops. A cheap line without an SLA gets expensive the first time it goes down during business hours.

Package type Typical speed Contention
Consumer fibre 10–100 Mbps 20:1 to 50:1
Business fibre 50–200 Mbps 10:1 to 20:1
Enterprise fibre 200 Mbps–1 Gbps 1:1 to 5:1

The hardware fixes that unlock your line

Your ISP’s connection is only as fast as your own network allows. This is where most offices quietly lose a third of their speed.

Upgrade the router. The free box bundled with a fibre line prioritises cost over performance and often lacks proper quality-of-service. A business-grade router (vendors like Ubiquiti, MikroTik and Draytek are common choices) gives you traffic prioritisation, dual or tri-band radios to cut congestion, gigabit ethernet, WiFi 6 for the long term, a real firewall and a management dashboard.

Wire what stays put. Desktops, printers and security systems belong on Gigabit ethernet (Cat6 or Cat6A). Wireless is convenient but slower and prone to interference, so reserve it for laptops and phones.

Segment the network. Put guest WiFi on its own VLAN so visitors cannot eat your business bandwidth, and separate departments or priority levels where it helps. For coverage across a larger floor, a mesh or multi-access-point setup beats one router straining to reach the boardroom.

Where your speed actually goes: the line vs your network

Fibre lineBusinessrouter + QoSWired: fast, stableWiFi: interferenceFixedMobile

A faster package fixes nothing if a single large download can still starve the whole office. Traffic rules, not more megabits, protect your calls.

WhichVoIP editorial view

How to set QoS so calls always come first

Quality of Service is the art of sending bandwidth where it matters. Without it, one person downloading a large file can tank everyone’s VoIP quality.

Tier 1 – criticalVoIP, video conferencing and cloud apps. Guarantee a minimum, for example 2 Mbps per active call, and tag by protocol (RTP) or port.
Tier 2 – highEmail and web browsing. Let it use up to about half the available bandwidth when the critical tier is quiet.
Tier 3 – backgroundBackups, updates and large downloads. Let these use whatever capacity is left after the higher tiers.
Use the presetsMost business routers ship with VoIP and video presets. Enable them on day one, and if your Cloud PBX uses specific ports, give those the highest priority.

How to monitor and troubleshoot slow speeds

Ongoing monitoring catches degradation before your team complains. Establish a baseline, then look for trends.

Run a speed test weekly at the same time of day using a reputable tool such as Speedtest.net (Ookla) or a South African-hosted tester that measures within local infrastructure. Record the results. If speeds consistently sit 20% below your contracted rate, that history is your evidence when you call the provider.

Symptom Likely cause First move
Slow on every device, wired and wireless, same time daily ISP-side or contention Log it, raise with provider
Only WiFi slow; ethernet fine Router or interference Reposition or replace router
Everything slow after an outage Session stuck Power-cycle modem + router

To isolate the problem, plug a laptop straight into the modem by ethernet. If wired speed is normal but WiFi is not, your router needs repositioning, reconfiguration or replacement rather than an ISP call.

A Small Ups Unit And A Fibre Router On A Shelf In A South African Office, Keeping The Connection Alive During A Power Outage
A modest UPS on the router and ONT keeps WiFi and calls alive through a power dip, buying 20 to 40 minutes or bridging to a generator.

Keeping the connection up when the power drops

Fibre itself carries light, not electricity, so the cable is fine during an outage. The equipment that turns that light into internet is not, and that is what you plan for.

Put the router on a UPSA 1000 VA unit keeps your modem, ONT and router online for roughly 20 to 40 minutes, so WiFi stays up and calls do not drop. Budget R1,500 to R3,000 for a business-grade unit.
Add a failover linePair fibre with a 4G or 5G mobile connection. When fibre drops, traffic reroutes automatically and the switch is seamless for users.
Keep critical services in the cloudEmail, CRM and backups hosted with redundant data centres stay reachable from any working connection, so a local outage becomes a non-event.
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Watch this: a UPS on the PCs but not on the router is a common miss. If the router loses power, everything is offline no matter what else is running. Protect the whole path from ONT to router first.

Our verdict

Faster fibre is the last lever to pull, not the first. Right-size the package with headroom, insist on a sensible contention ratio and an SLA, then invest the real effort in your own network: a proper router, wired connections where they count, QoS that protects voice, and a UPS-plus-failover plan for power. Do that and the line you already pay for will perform like a faster one.

Our recommendation: audit your current speed against your contracted rate this week, fix the router and QoS first, and only upgrade the package if the numbers still fall short.

Outgrown your current fibre line?

Compare business fibre packages on speed, contention and SLA, and get quotes matched to your team size.

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Frequently asked questions

Why is my fibre slower than the speed I pay for?
The most common causes are your own router and WiFi, not the ISP. A bundled router without QoS, interference, or a device on WiFi that should be wired all cap real-world speed. Test with a laptop plugged straight into the modem: if that is fast but WiFi is not, the fix is on your side.
What upload speed does a business need on fibre?
Aim for upload at least 50% of your download, and closer to symmetrical if you run cloud backups, video calls or VoIP. Consumer packages skimp on upload, which is exactly what business applications depend on.
What is a contention ratio and why does it matter?
Contention ratio is how many users share the same upstream capacity. A 20:1 ratio means peak-hour slowdowns are likely; premium business lines offer 5:1 or lower. It is the single most overlooked spec when comparing packages that look identical on speed and price.
How do I keep VoIP calls clear when the office is busy?
Enable quality-of-service on a business-grade router and give VoIP and video the top priority tier, with a guaranteed minimum of about 2 Mbps per active call. That stops a single large download from starving your calls of bandwidth.
How do I keep internet running during load shedding?
Fibre works during an outage, but the router and ONT need power. Put them on a 1000 VA UPS (about R1,500 to R3,000) for 20 to 40 minutes of runtime, and add a 4G or 5G failover line that takes over automatically if fibre drops.
Should I upgrade my package or my hardware first?
Hardware first, almost always. Right-size the package with headroom, then fix the router, wiring and QoS. Most offices recover a third of their apparent speed loss from hardware and configuration before they ever need a faster line.

Keep reading

How much internet speed a contact centre needs
Choosing the best fibre package for business
Best business WiFi solutions in South Africa
Compare fibre providers

Sources: WhichVoIP editorial guidance on South African business fibre; Ookla Speedtest methodology for baseline testing. Speed, contention and SLA figures are typical 2026 SA market ranges, not a single provider’s package. Verified 14 July 2026.


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