Optimize network interface port speed and duplex to increase network performance

    This article explains how duplex and speed can affect your network data transfer capabilities.


    Have you ever been curious if your network is performing at its best? It's completely possible that it's not, so let's check a few settings.

    Sometimes, a network setup—whether internal or from your ISP—may hold you back from peak performance. And usually, there are two features that cause the most issues: interface speed and duplex configuration. This isn’t anyone’s fault. Most devices handle this stuff automatically that many people never check in on these two areas. /span>

    This article explains what these settings do, and how to make sure they’re configured in a way that’s ideal for your work needs.


    Before you dig in and start making changes to your network equipment, you’ll need access to your network devices (portal/command access). Some of the settings we’ll address here require you to be logged in to specific devices or sync with your IT company to handle the changes for you.

    Network interface speed

    Each network interface, or the physical port that the network cable connects to on a router, firewall, or computer, has a hardware speed limitation and a software speed configuration. 

    Hardware speed limitation: the maximum speed the network interface or port can physically transfer data, measured in megabytes (Mbps) or gigabytes (Gbps)

    Software speed configuration: gives the option to create speed limitations on the port of a router, firewall, or personal computer. For example, if you have a hardware port speed limit of 1000 Mbps, you can set the interface speed to only 100 Mbps if needed, or choose any option up to the full 1000 Mbps. Lowering the speed is often done to limit excessive usage on a network

    Network interface duplex

    The port on a router, firewall, or computer also has an option for configuring duplex. 

    Duplex setting: tells the port whether it should send traffic in only one direction at a time (half-duplex) or in both directions at the same time (full-duplex). Having full-duplex is the better option since it allows data to travel in both directions at the same time.

    Checking network devices speed and duplex

    Now that we’ve cleared up what speed and duplex mean, you can put that knowledge to use by checking your existing settings. 

    If your connection seems slower than you anticipated, it’s a good idea to check the capable devices for those settings. The best place to start is the device connected to your ISP’s equipment (modem) and go from there. 

    Most manufacturers have a quick step-by-step guide to finding and configuring your speed and duplex. Search the make and model of your device or operating system to get the right steps needed to make those changes. While you look through the settings, you may see some device configurations set to auto-negotiation by default. 

    Auto-negotiate automatically uses the best settings available on that interface. If you have a device connected that cannot support the full speed and duplex, it will automatically optimize for the slower device. We recommend using the auto-negotiate setting on your devices if they aren’t already configured for it.


    In most situations, “automatically” is a good thing. But when it comes to interface speed and duplex, it’s best to double-check device defaults and look over any potential areas you should handle yourself.

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