top of page
  • Writer's pictureAnthony Jones

When is Gigabit internet not Gigabit?

A common question is, “I have Gigabit Internet in theory, but only get a fraction of that in practice. Why?” In almost every case, the answer to this is, “Because your network isn’t good enough to support Gigabit internet effectively.”

A good way to think about this is that your Internet speed is the water pressure at the point at which water enters the house, while your home network is the piping and taps and shower-heads inside the house. You can have the greatest water pressure from the street in the history of plumbing, but if you have thin pipes and rusty taps and a useless shower, that’s not going to matter a great deal. So it is with your Internet connection. It is extremely common for users to purchase a Gigabit Internet package, or similar, and then to connect it to a home network that is running at a fraction of that speed—or, at the very least, that has a bottleneck somewhere within their chain that cuts the speed to a crawl. This guide will run you through the necessary steps to make sure that you get as much out of your fast internet connection as possible.

If your ethernet adaptor isn't up to the task, you will show the fastest possible connection AFTER the choke point. Also, you're getting a gigabit in, the 1000mbps are shared between however many devices are on the network at any one time, and how this is divided depends on how they connect, ie wired or WIFI.

Even with a hardwired gigabit connection to the home/ONT, the overheads are approximately 9%, so roughly 90mbps are taken up with actively directing or controlling the transfer of user information or the detection and correction of errors. So on a standard speed test it is almost impossible for your device to show 1000Mbps, it will most likely fall within the 900-950Mbps range,

Check Your Router

Your router is almost always the first unit within your internal network, and thus is usually the first choke-point that can slow down your Gigabit Internet connection. In most networks, the purpose of a router is to send traffic between (1) the array of devices that are connected to it locally, and (2) the Internet outside. The diagram below shows you the order in which core devices are connected in a typical home network:

Because it serves as the “gate” between your home network and the outside Internet, the maximum speed at which your router translates data between the two is, practically speaking, also the maximum speed of your internet connection. For example, if you have an Internet connection that runs at 1,000mb/s (Gigabit) and a modem that runs at 1,000mb/s (Gigabit) but a router that maxes out at 300mb/s, then in practice the maximum internet speed that any device is going to get is 300mb/s. Or put another way: To enjoy a Gigabit network, you need a Gigabit router. If you are using a combination modem/router that was provided by your ISP, check with them that it supports the speeds for which you are paying. If you are using you own, check to see what the maximum throughput is. You may find that it is too slow for your new connection.

Note that the key variable when looking at router speed is not how fast a router can transfer data between devices connected to it locally, but rather how fast a router can translate data from its WAN port (the port to which the outside connection is connected) to its LAN ports (the port(s) to which inside devices are connected) or its Wi-Fi antennae. On most consumer equipment, these two speeds are different—and considerably so. The Apple Airport Extreme, for example, can handle local traffic at the full 1000mb/s, but translates from WAN to LAN at a maximum of only ~330mb/s. To get an accurate grasp of the difference between your internet speed as delivered to your home, and your internet speed once filtered through your router, perform the following test:

Connect a fast computer directly to your modem, and run one of the many speed tests that are available online. The two most reliable tests are by and nPerf. The maximum speed you get with this direct connection is what you’re ideally aiming for on the rest of your network.

Repeat this test, with the same computer, behind your router. If the speed drops, your router is acting as a chokepoint.

The WAN to LAN behavior described above does not apply to IPv6 traffic, which is not “translated.” That, however, is beyond the scope of this article.

Check Your Switches

In addition to a router, some networks have one or more “switches” installed at various points in the chain. Essentially put, a switch is used to “cross-connect” wired devices together. Suppose that you have a single ethernet cable running into your office but have five wired devices you need to add to your network. Well, by plugging both the single ethernet cable that runs into your office and the cables from each of your five devices into the switch, you can put them all on the same network. As an example, the diagram below adds a switch to the hypothetical network outlined above:

To ensure that your switch is not serving as a choke point, ensure that your switch is capable of switching data at 1,000mb/s (Gigabit). If you do not, anything behind your switch will run at the switch’s maximum throughput, which, obviously, can be significantly slower than you need.

Check Your Wi-Fi

Wi-Fi is a little more complicated a topic than routers or switches, because the speeds associated with its different protocols are more theoretical than is the case with wired devices. As a rule, wired connections are extremely efficient and are not affected a great deal by external factors within your home. This is not at all the case with wireless, the speed and reliability of which can be dramatically reduced by, among other things:

Walls, floors, and other physical structures

Competing radio signals, including other people’s Wi-Fi

Cell phones, cordless phones, baby monitors

Garage door openers

Microwaves (amazingly, 2.4Ghz is the frequency used by most Wi-Fi units and by most microwaves)

The number of devices wirelessly attached in a given location

How far away your devices are from the original Wi-Fi signal

There are two “bands” currently in use by consumer Wi-Fi devices: 2.4Ghz, and 5Ghz. The maximum theoretical speed within the 2.4Ghz band is 450mb/s (802.11n). The maximum theoretical speed within the 5Ghz band is 1300mb/s (802.11ac). That word “theoretical” is important: In the real world, because of the interference described above, it is rare to get anything like these speeds. If you can, run a wire.

Nevertheless, there are some important things you can do to maximize your Wi-Fi speed, and thus to get as close as possible to experiencing your Gigabit Internet at full speed.

Make sure that your Wi-Fi access point — or you router, if your router has built-in Wi-Fi — supports the 802.11ac standard, and that you have switched on the 5Ghz band. There is no reason to switch off the 2.4Ghz band when you do this. The two can co-exist, and it can be useful to have both, given that, while it is slower, the 2.4GHz band has greater range.

Avoid connecting Wi-Fi access points together using Wi-Fi. If you have more than one access point—or if you are using a “mesh” network such as Google Wi-Fi—try to connect the units together using ethernet cables where possible. This will ensure that the communication between the Wi-Fi devices runs at full speed, and that you are not wasting bandwidth on internal communication.

If you have multiple wireless access points—and if their physical coverage overlaps—check to see if you can customize their RSSI values (received signal strength indicator). By setting a minimum RSSI setting on each access point, you can suggest to each device on the network which access point is the best fit.

Check Your Devices

Obviously, the devices on your network (e.g. the computers, phones, games console, etc.) also have to be able to support your network’s maximum speed, or they themselves become chokepoints. Ensure that wired devices from which you need high performance have Gigabit (“10/100/1000”) ethernet cards, and that wireless devices have at least 802.11n, and preferably 802.11ac, capability.

Check Your Cables

It is extremely unlikely that you will be using ethernet cables incapable of supporting Gigabit, but it’s worth making sure. Cat5e, Cat6, Cat6a, and Cat7 are all guaranteed to support Gigabit. Old Cat5 cables (non-“e”) can support Gigabit over short distances, but it is not guaranteed.

Cables and other related equipment are available on my store should you require any additional items.

78 views0 comments

Recent Posts

See All


bottom of page