Check out our UniFi Expert's Corner video for a quick overview of wireless speeds. Follow these guidelines, and those in Optimizing Wired Network Speeds, to maximize your total network throughput.
Wireless throughput is affected by more than just how you configure your network and UniFi Access Points (APs). This article will explore the most common causes of slow speeds and provide suggestions for improving them.
Before you continue, please note that maximized speeds are not the ultimate benchmark of a high-performance network. For context, streaming Ultra HD content on Netflix only requires 25 Mbps of bandwidth. Achieving the highest rate possible isn’t required to ensure quality connectivity. As such, your most pressing concern should be achieving stable speed and bandwidth rates that reliably support all connected devices.
Setting Realistic Expectations
Unlike wired connections that support full-duplex communication, wireless communication is half-duplex. This means that a 1 Gbps wireless connection can only support a simultaneous upload/download speed of 500 Mbps.
Furthermore, wireless protocol overheads typically result in 25-40% speed reduction compared to the theoretical maximum. This applies to all vendors and wireless access points.
In general, it is safe to assume that you are in good shape if you are achieving ~50% of your theoretical maximum speeds.
Increase Your Channel Width
Larger channel widths allow for faster speeds. Doubling your channel width will nearly double your wireless speed. Increase widths cautiously, though, as this will decrease your WiFi range and could increase channel interference. High-density or crowded RF environments with a large channel width can decrease network performance and cause more device disconnections.
UniFi Network supports the following channel widths:
- 2.4 GHz: 20 MHz (Default) / 40 MHz
- 5 GHz: 20 MHz / 40 MHz (Default) / 80 MHz / 160 MHz
Larger channel widths result in more interference. If you have a high-density deployment or high utilization, we recommend reducing your channel widths.
Use Band Steering to Move Compatible Clients to 5 GHz
UniFi APs currently only support the 2.4 and 5 GHz bands. Soon, we will launch the U6-Enterprise which will support the upcoming 6 GHz standard and deliver the fastest possible WiFi speeds. Here’s a simple breakdown of the two currently supported bands:
- 2.4 GHz: Delivers slower speeds and more interference, but broadcasts further due to better signal penetration through solid surfaces.
- 5 GHz: Delivers faster speeds and offers less-crowded channels. However, some legacy clients are incompatible with the band.
Enable Band Steering to automatically move compatible clients to the 5 GHz band.
Improve Client Signal Strength
To maximize your speeds, we recommend maintaining signal strengths between -50dbm and -60dbm. Numbers closer to zero indicate higher signal strength and throughput.
You can improve your signal strength by:
- Moving clients closer to your AP.
- Adding more APs to your network.
- Setting your TX power to Auto or High.
Note: Increasing the transmit power of your devices can negatively impact their performance, especially in a very high density environment.
Select Non-Overlapping and Low-Interference Channels
We recommend enabling Nightly Channel Optimization to ensure you are on the least-crowded, non-overlapping channels. Your network will continue to work during nightly scans.
Wireless clients use a shared airspace for communication. This is true for all devices in a given area, even if they are not connected to your network (e.g., your neighbor has a lot of IoT devices). This is why having high-density deployments may contribute to speed or connectivity issues.
If you prefer to manually assign channels, here are a couple of rules to keep in mind:
- If you must use 2.4 GHz, you should only ever use Channel 1, 6, or 11. These will optimize connectivity since they are the only non-overlapping channels.
- Nearby APs should use different channels. If you have three APs, you can set one each to Channel 1, 6, and 11 on the 2.4 GHz band. This concept applies to 5 GHz as well.
- You can perform an RF Scan in the UniFi Network Application to identify channels with the lowest interference. Unlike Nightly Channel Optimization, this scan may interrupt client connectivity while in progress.
Use APs That Support the Latest WiFi Standards and Technology
Each AP has its own specifications (such as WiFi standard or supported MIMO streams) that affect its maximum speeds. For optimal performance, we recommend our WiFi 6 access points.
Ensure That Your Clients Support the Latest WiFi Technology
Client specifications are just as important as your AP’s. A legacy client connected to the 2.4 GHz band using the WiFi 1 (802.11b) standard with 1x1 MIMO support will never be able to experience the benefits of your U6 Pro (e.g., 5 GHz WiFi 6 connectivity, 4x4 MU-MIMO and OFDMA functionality, etc.).
Remove Upstream Bottlenecks from Your Network
It is important to identify any bottlenecks throttling your speeds. For example, a wireless client will never achieve a 25 Mbps Netflix stream if it is limited by a 10 Mbps Internet connection or switch port / Ethernet connection upstream.
Minimize Meshed Network Usage
It is always preferable to hardwire APs to your network. Wirelessly meshing APs typically results in a ~50% throughput reduction per hop. If you prefer a meshed network, we recommend no more than two hops between a downstream AP and its first hardwired uplink.
Expedite Your Support Request
Prior to reaching out to support, we recommend gathering/verifying the following information. Including these details in your request will expedite your support experience.
- What are your expected speeds?
- How widespread is your throughput issue? Does it affect wired clients, wireless ones, both, or just certain devices?
- What is your channel width? You can find this in your Global AP Settings, or by opening the device details panel of a specific AP.
Also, please include the following information, which can be found by selecting the affected device(s) on the Client Device page in your Network application.
- Make and model
- Band utilization (2.4 or 5GHz)
- MIMO support (e.g., 1x1, 2x2)
- WiFi standard (e.g., WiFi 5, WiFi 6)
- Signal strength while experiencing reduced throughput