Slow Internet? (Maybe) Don’t Blame Your ISP

When it comes to customer satisfaction, or rather dissatisfaction, it’s hard to beat an Internet Service Provider. With government-sanctioned duopolies limiting any real competition in the vast majority of the United States, your local cable or phone company has little incentive to strive towards anything more than mediocrity. But while stories of ISPs behaving badly abound, these companies often shoulder the blame for things that really aren’t their fault.

Take the speed of your connection for example. Whether it’s delivered through cable, phone lines, or fiber optic connections, all ISPs are consistently dinged in customer reviews for delivering less than the advertised speed. But the speeds reported by sites like or are really giving you the speed of the weakest link in an increasingly complex mesh of different connections. It’s entirely possible for that weakest link to be somewhere other than your ISP.

To illustrate this it’s helpful to think of a long road-trip. Large portions of the trip may take place on empty highways with speed limits of 70mph or more, but the total time it takes to get from point A to point B is still limited by smaller roads with lower speed limits, traffic in major areas, road construction etc. You can’t blame those big empty highways for the delays imposed on other parts of the trip.

When it comes to connectivity, those limiting factors can often be somewhere on our local networks, before the traffic even reaches the ISP. Wi-Fi is the biggest culprit here, having historically been far slower and less reliable than a wired connection. It’s such a common issue that it’s often the first question an ISP’s tech support rep will ask when faced with a speed complaint. But everything from a misconfigured switch port to a bad cable or overtaxed router can limit the overall speeds experienced by users. 

Just how big a difference can these things make? Here’s some real speed tests from my own home network:

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You can see a pretty significant bump in speeds from January 28 to February 2. There’s no plan upgrade here; I’m on the same 300Mbps plan I’ve had for a a full year now. What is different is the equipment. The previous setup consisted of an old Apple AirPort Extreme acting as a wired switch and router, with wireless functionality coming from a modern, enterprise-grade wireless access point from Cisco. In the current setup, the CPU-intensive routing is being perfomed on an eight-core server running an open-source firewall project called pfSense.

Despite the “extreme” moniker, the AirPort Extreme, like most consumer-grade routers, never had a particularly powerful processor. As Internet speeds have increased over the decade or so since it was released, it no longer has the horsepower required to translate packets between external and internal network addresses at a fast enough to match the speed of my connection, resulting in speed tests of only about 215-230 Mbps downstream. Moving to a platform with a lot more processing power removed that bottleneck and enabled higher speeds. As an interesting note, I’m still using the AirPort Extreme as a switch; unlike routing, switching does not require much computational power, so the AirPort is no longer limiting the total speeds I can achieve.

An overtaxed router is actually somewhat unusual; there’s plenty of other culprits that you’ll see more often. In both small and large business networks, firewalls or security appliances can be common sources of slowdowns. Features like Intrusion Detection or Protection Systems (IDS/IPS), Deep Packet Inspection (DPI), and Virtual Private Networks (VPNs) are very CPU-intensive. Since these devices sit in between the user and the outside world, any slowdown here will limit overall performance. This can also be a particularly common problem on devices where routing and security features are combined, as a single CPU has to deal with multiple functions at once.

Even something as basic as a bad cable can cause major issues. A few a few months ago I spent hours trying to figure out why a single link in a brand new Ubiquity-based setup I’d installed for a client was operating at a suboptimal speed. After resetting everything, upgrading device firmware, and a lot of head scratching I finally swapped the network cable and everything worked like a charm. If your Internet is delivered through Cable or DSL, the quality and the condition of the wiring inside your home or building can also make a dramatic difference.

There’s also a solid possibility that there’s nothing wrong with either your network  or your ISP. Slowdowns can and do occur on the other side of the connection, where the website, server, or application resides. Misconfiguration, hardware failure, denial of service attacks and more impact companies as large as Facebook, Google and Amazon. Network congestion at intermediate points along the way can also affect performance, as can equipment failures, power loss, and even a ship’s anchor cutting through undersea communication cables.

So the next time you’re dealing with slow Internet, think twice before blaming your ISP.

If you need help diagnosing connectivity issues or poor performance, please don’t hesitate to contact us!