Most businesses shop for internet the same way they shop for a phone plan. They look at the speed, compare the price, and pick the biggest number they can afford.
Then the connection drops in the middle of a payroll run, or a sales call, or a busy Friday at the register. Suddenly it’s not a matter of top speed. It’s a matter of who’s responsible for getting you back online.
When business relies heavily on reliable connectivity, it pays to have some guarantee of service. That guarantee for business internet is a Service Level Agreement (SLA). It turns the contract between you and the internet provider from “we hope your internet stays up,” to “here is what we promise, in writing.”
It is the difference between a connection that is fast on a good day and a connection your business can actually count on.
This guide breaks down what a business internet SLA covers, why an uptime guarantee can matter more than a the fastest speeds, and how to read one before you sign.
A business internet Service Level Agreement (SLA) is a written, contractual promise from your provider that defines the level of service you will receive. It sets specific, measurable targets for things like uptime, repair times, and network performance, and it spells out what the provider owes you if those targets are missed.
An SLA answers addresses three issues:
It’s also one of the distinguishing factors between consumer and business internet. SLAs are rare with consumer internet plans. But they’re quite common with Business internet.
Speed tells you how much data can move when everything is working. An SLA tells you what happens the rest of the time.
Picture two connections. One advertises a blazing 2 Gbps but runs on shared, best-effort infrastructure with no uptime promise. The other delivers a steady 500 Mbps on a dedicated line backed by a 99.999% uptime SLA. The first one wins a speed test. But, over a year of real operations, the second one keeps your point-of-sale terminals, VoIP phones, and cloud apps running while the first one leaves you waiting during every outage.
Commercial connections prioritize reliability and consistent performance, often through dedicated bandwidth and SLAs, where home plans are built mostly for streaming and browsing.
More than 90% of mid-size and large enterprises say a single hour of downtime costs them over $300,000, and 41% put the figure between $1 million and more than $5 million per hour. (ITIC, September 2024) Even for a micro business with fewer than 25 employees, downtime cost estimates are roughly $25,000-$75,000 an hour, which may be a conservative estimate.
Those losses are not just missed sales. They stack up across idle payroll, stalled orders, frustrated customers, and the scramble to recover. A team that cannot work still gets paid. An online store that cannot load still owes refunds and customers to serve.
An SLA does not prevent outages. What it does is put your provider on the hook to keep them rare, fix them fast, and compensate you when they do not.
Uptime percentages look reassuring until you translate them into real time. The gap between “three nines” and “five nines” sounds tiny. In practice, it is the difference between most of a workday offline and a coffee break.
Here is how common uptime guarantees convert into allowed annual downtime:
Uptime SLA | Nickname | Downtime per Year | Downtime per Month |
99% | Two nines | About 3.65 days | About 7.3 hours |
99.9% | Three nines | About 8.8 hours | About 44 minutes |
99.99% | Four nines | About 52 minutes | About 4.4 minutes |
99.999% | Five nines | About 5 minutes | About 26 seconds |
A jump from 99.9% to 99.99% may not seem like much, but for a business that runs on cloud software, card payments, or internet phones, it’s a significant, costly gap.
Uptime gets the headlines, but a strong SLA covers more than a single percentage. When you read one, look for these pieces.
This is the core promise: the percentage of time the network will be available over a billing period. Watch for how the provider defines availability, what counts as an outage, and whether scheduled maintenance is excluded from the calculation.
Speed is not the only performance benchmark that matters with an internet connection. Latency is a measurement of response, or delay. Jitter is how much that delay varies. Packet loss is a measurement of how much data never arrives to the intended destination. When these are not performing well, you’ll notice choppy video calls and distorted VoIP call audio.
An SLA puts targets on them. For example, an SLA might determine a goal of round-trip latency at or under 40 ms within the contiguous U.S. and monthly packet delivery of 99.5% or better. If your work depends on calls or real-time apps, a dedicated fiber internet connection with an SLA that includes clear latency and packet delivery is an ideal solution.
An outage is not just about how often it happens. It is about how long it lasts. Mean Time to Repair, sometimes written as Time to Repair (TTR), is the provider’s promise on how quickly they will restore service after a problem is reported. A “4-hour SLA” usually means the provider commits to resolving qualifying outages within four hours, often with a credit owed if they’re outside that window.
A promise with no consequence is just marketing. This section explains what you get when the provider misses a target, usually a credit applied to your bill that scales with the severity or duration of the failure. Read it closely. Some credits are generous and automatic. Others are small, capped, and only paid if you file a claim within a tight window.
The best SLAs back the network with people. Look for 24/7 support, guaranteed response times, proactive monitoring, and a real human you can reach instead of a chatbot loop. When something breaks at 2 a.m., the quality of the support team is the SLA in action.
Most business outages trace back to one root cause: a shared, best-effort connection with no uptime guarantee. Best-effort broadband splits bandwidth among many users in your area. When that shared network gets busy, your speeds dip, and there is no contractual obligation to protect you. It is often cheaper, and for a small office doing email and light browsing, it can be enough.
SLA-backed dedicated internet works differently. You get a private connection reserved for your business, with symmetrical upload and download speeds and performance the provider is contractually bound to deliver. EarthLink Business describes this as the gap between sharing your connection with strangers and owning a dedicated, uncontested fiber line built only for you and your business. For operations that cannot afford to go dark, that difference is the entire decision.
SLAs are fairly straightforward but read yours carefully. You need to ask the right questions. Before you sign, run the contract through this checklist:
If a provider cannot answer these clearly, that is your answer. A real SLA is specific. Vague language usually means a weak guarantee. Have your general counsel or an attorney review it to ensure you’re getting the service levels your business needs.
EarthLink Business builds its pitch around a simple idea: it delivers more than just speed. Across its fixed wireless and dedicated fiber services, EarthLink backs its network with a Service Level Agreement promising 99.999% uptime on its , which works out to roughly five minutes of downtime per year.
That promise is paired with the support that makes an SLA mean something. EarthLink runs an onshore, fully monitored Network Operations Center (NOC) that tracks the health of your connection in real time, offers 24/7 U.S.-based support staffed by real people instead of chatbots, and assigns a dedicated account manager from day one. Connections are dedicated and symmetrical, with speeds scaling up to 10 Gbps.
If you want to know what your business should expect from an SLA-backed connection, the EarthLink Business team can check availability and walk through the guarantee at 844-356-5249.
SLA stands for Service Level Agreement. It is a contractual promise that defines the level of service a provider will deliver, including measurable targets for uptime, performance, and repair times, plus the remedies owed if those targets are missed.
For most businesses, 99.9% (three nines) is a reasonable baseline, and 99.99% or higher is strong. Mission-critical operations often look for 99.999% (five nines), which allows only about five minutes of downtime per year. The right level depends on how much an hour offline would actually cost you.
A 99.99% uptime SLA, known as “four nines,” guarantees that your internet will be available 99.99% of the time. That permits roughly 52 minutes of downtime per year, or about 4.4 minutes per month.
A channelized T1 divides its 1.544 Mbps of bandwidth into 24 separate 64 Kbps channels, which can be allocated to voice calls, data, or a combination of both. An unchannelized T1 — also called a Data T1 — dedicates the full 1.544 Mbps to data transmission only, making it faster and more efficient for internet access. Businesses that need both voice and data on a single line typically use an integrated T1, though sharing the connection between both uses reduces effective throughput for each.
When a provider misses an SLA target, compensation typically comes as a service credit applied to your bill. The credit usually scales with how severe or how long the failure was. Some credits are issued automatically, while others require you to submit a claim within a set time frame, so read the remedies section carefully.
Generally, no. Residential internet is sold as a best-effort service with no contractual uptime guarantee. SLAs are a defining feature of business-class connections, which is one of the main reasons companies choose business internet over a consumer plan.
