SLAs: The Contract Language That Actually Matters

Getting the Internet Right: Part 9 of 12

If you've been reading this series, you've seen the term SLA come up multiple times. It showed up when we talked about dedicated internet access, when we compared shared versus dedicated fiber, and in passing when discussing almost every connection type. That's because the SLA, which stands for Service Level Agreement, is often the single most important difference between a connection that's being sold as a business product and one that just happens to be available to businesses.

An SLA is, at its most basic, a set of promises that the provider puts in writing about the performance and availability of their service. It's also a set of remedies that define what happens when those promises aren't kept. Understanding what's in an SLA, what's typically not in one, and how to tell a strong SLA from a weak one gives you a much clearer picture of what you're actually buying when you sign a contract with an internet provider.

What an SLA typically covers

A standard ISP SLA for a business connection addresses several categories of performance. Not every SLA covers all of these, and the specific guarantees vary significantly from provider to provider. Here are the main ones to look for.

Uptime guarantee. This is the big one. The uptime guarantee expresses, as a percentage, how much of the time the provider commits to having your connection available and operational. You'll commonly see figures like 99.9%, 99.95%, or 99.99%.

These numbers look very similar at first glance, but the differences are significant when you translate them into actual downtime. A 99.9% uptime guarantee allows for about 8 hours and 45 minutes of downtime per year. A 99.99% guarantee allows for about 52 minutes. That's the difference between a full business day of outage being within acceptable bounds and less than an hour per year being the maximum.

When evaluating an uptime guarantee, pay attention to how the provider defines "downtime." Some providers define downtime as a complete loss of connectivity to your premises. Under that definition, a circuit that's up but performing so poorly that your phones are unusable and your cloud apps are timing out might not count as downtime. A better SLA defines downtime as failure to meet any of the performance guarantees, not just total loss of connectivity.

Also check whether the uptime guarantee excludes scheduled maintenance. Many SLAs do, meaning the provider can take the circuit down for maintenance and that time doesn't count against their uptime commitment. This is fairly standard, but you should know what the maintenance windows look like and how much advance notice you'll get.

Latency guarantee. This specifies the maximum round trip latency between your connection and the provider's backbone, or between their backbone and certain measurement points on the internet. A typical latency guarantee for DIA might be something like "less than 40 milliseconds round trip within our network." This is important for VoIP because, as we covered early in the series, excessive latency creates conversational delays that make phone calls feel unnatural.

Packet loss guarantee. This specifies the maximum acceptable rate of lost packets on the provider's network. A strong SLA will guarantee less than 0.1% packet loss. Some guarantee less than 0.01%. For voice traffic, even small amounts of packet loss cause audible quality degradation, so this number matters.

Jitter guarantee. Some SLAs include a maximum jitter figure, though this is less common than latency and packet loss guarantees. If it's included, you'll typically see a guarantee of less than 1 to 5 milliseconds. Given how sensitive voice is to jitter, having this in the SLA is valuable if you can get it.

Mean Time to Repair (MTTR). This specifies how quickly the provider commits to restoring service after an outage. A typical MTTR guarantee for DIA might be 4 hours. Some premium services offer 2 hours or even 1 hour. This doesn't mean every outage will be fixed within that window, but it sets an expectation and a baseline for credits if the provider exceeds it.

What happens when the SLA is violated

The enforcement mechanism in most SLAs is the service credit. If the provider fails to meet a guaranteed metric, they owe you a credit against your monthly bill. The credit amount is usually calculated as a percentage of your monthly recurring charge for each increment of time that the guarantee was missed.

For example, an SLA might specify that for each hour of downtime beyond the guaranteed uptime, you receive a credit equal to 5% of your monthly bill, up to a cap of 30% or 50% of one month's charges.

Let's be realistic about what this means. Service credits are not a windfall. They're not going to cover the business impact of a major outage. If your phones are down for six hours and you lose $10,000 in sales opportunities, a $200 credit on your $600 monthly bill doesn't make you whole.

What service credits do accomplish is creating an incentive structure. The provider has a financial motivation to meet their guarantees because SLA credits come directly out of their revenue. Providers also track SLA performance internally, and poor performance affects their operational metrics. The SLA creates accountability even when the dollar amounts of individual credits are small.

Claiming SLA credits

Here's something most businesses don't realize: in many cases, you have to proactively claim SLA credits. The provider won't automatically credit your account when they miss a guarantee. You need to notice the issue, document it, submit a claim within a specified time frame (often 30 days), and the provider then evaluates the claim against their records.

This means you need to be monitoring your connection's performance, at least at a basic level, to know when the SLA is being violated. You also need to read the SLA's claims process so you know the deadline and requirements. Many valid SLA claims go unclaimed simply because the customer didn't know about the process or didn't submit the paperwork in time.

Some providers have started making this process more transparent, with dashboards that show performance metrics and automated credit processing. If you're evaluating two similar DIA proposals, the provider with a more transparent SLA credit process is, all else being equal, the better choice.

Shared connections and SLAs

One of the most significant differences between shared and dedicated connections is the SLA, or the lack of one.

Most cable internet plans, even business ones, either don't include a meaningful SLA or include one that's so weak it barely qualifies. A typical cable business SLA might guarantee uptime with generous exclusions but include no guarantees whatsoever about latency, jitter, or packet loss. The connection could be up but performing terribly, and the SLA hasn't been violated.

Shared fiber products are similar. Some include modest SLAs, but they generally don't guarantee the performance metrics that matter most for voice quality. You might get a vague commitment to "best effort" performance, which means the provider will try but doesn't promise anything specific.

DIA connections come with the strongest SLAs. Guaranteed uptime with narrow exclusions, guaranteed latency, guaranteed packet loss, often guaranteed jitter, and defined remedies for violations. This is a major part of what you're paying for with the premium pricing of DIA.

If your VoIP provider ever tells you that your call quality problems are on the ISP side, having an SLA with performance guarantees gives you something concrete to hold the ISP accountable with. Without an SLA, you're left explaining symptoms and hoping the provider investigates. With an SLA, you can point to specific guaranteed metrics and say, "You committed to less than 0.1% packet loss, and my monitoring shows 2% over the last week."

Reading between the lines

A few things to watch for when evaluating SLAs:

Credit caps. Most SLAs cap the total credits you can receive in a billing period, typically at 30 to 100% of one month's charges. This means that even in a catastrophic outage lasting days, your maximum credit is one month free. Know what the cap is and consider whether it's reasonable given the impact an extended outage would have on your business.

Exclusions. Read the exclusion list carefully. SLAs commonly exclude downtime caused by scheduled maintenance, force majeure events, issues with your equipment, issues with services or networks outside the provider's control, and outages you cause or contribute to. These exclusions are mostly reasonable, but some providers have creative exclusion language that narrows their obligations more than you'd expect.

Measurement methodology. How does the provider measure the guaranteed metrics? Do they measure at your premises, at their edge, or at some other point? A latency guarantee that only covers the provider's backbone network and excludes the last mile isn't covering the segment that's most likely to have issues.

Term versus month to month. Some SLAs are only available on term contracts (12, 24, or 36 months). The SLA on a month to month arrangement, if there is one, may be weaker. Understand what you're getting and what commitment you're making in return.

The bottom line on SLAs

An SLA is not a guarantee that nothing will ever go wrong. Things go wrong with every provider, every connection type, and every technology. What an SLA gives you is a clear set of expectations, a defined measurement framework, and a mechanism for accountability when those expectations aren't met.

For businesses that depend on their internet connection for revenue generation, customer communication, and daily operations, the presence and strength of the SLA should be a significant factor in the buying decision. Not the only factor, but one that deserves real attention rather than being treated as fine print to skip past.

Next up: Redundancy and Failover: When One Connection Isn't Enough, building a backup plan for the thing that everything depends on.