How to Configure Roaming on UniFi Access Points

Configuring Roaming Parameters on UniFi Controller 9.5.21 for Access Points

To configure roaming parameters on a UniFi controller version 9.5.21 for access points, you need to optimize the Minimum RSSI parameters, enable fast roaming protocols 802.11r/k/v, properly configure access point channels and power, and use the Roaming Assistant function to manage transitions between access points. The main problem with connecting to a distant access point at the entrance is solved by setting the optimal Minimum RSSI value in the range of -70 to -75 dBm and ensuring coverage overlap of access points at the level of -68 dBm.

Table of Contents

• Basic Roaming Parameters in UniFi 9.5.21
• Setting Up Minimum RSSI for Connection Management
• Fast Roaming Protocols 802.11r/k/v
• Optimizing Access Point Placement and Power
• Using Roaming Assistant
• Recommendations for Channels and Coverage Overlap
• Practical Configuration and Testing

Basic Roaming Parameters in UniFi 9.5.21

UniFi controller version 9.5.21 provides several key parameters for fine-tuning roaming between access points. The main parameters are located in Settings → WiFi → SSID Settings and Devices → Access Points → Settings. It’s important to understand that the UniFi controller doesn’t manage roaming directly but configures parameters on the access points themselves, which then decide when a client should switch to another access point.

Main parameters affecting roaming:

• Minimum RSSI - minimum signal level for maintaining connection
• Minimum Data Rate - minimum data transfer rate
• Roaming Assistant - function for managing transitions
• Channel Width - performance and interference configuration
• Transmit Power - coverage area control

Important: For successful roaming, you need to ensure coverage overlap between neighboring access points of at least 15-20%, so that clients have a choice between multiple access points in overlap areas.

Setting Up Minimum RSSI for Connection Management

Minimum RSSI (Received Signal Strength Indicator) is one of the most important parameters for managing roaming. This parameter determines the minimum signal level (in dBm) at which a client will maintain a connection with an access point. When the signal level drops below this value, the client starts searching for another access point with a stronger signal.

Optimal values for Minimum RSSI:

• For office environments: -70 to -75 dBm
• For densely populated areas: -68 to -72 dBm
• For open spaces: -75 to -80 dBm

According to research, setting a value in the -70 dBm range often solves the problem where clients remain connected to a distant access point. Research shows that values in the -70 to -75 dBm range are optimal for most office environments.

How to configure Minimum RSSI:

1. Go to Devices → Access Points
2. Select the desired access point
3. Go to the Settings tab
4. Find the Minimum RSSI parameter and set the value
5. Apply settings to all access points

Warning: Too aggressive values (below -75 dBm) can cause constant reconnections, while values that are too high (above -65 dBm) won’t allow clients to switch to closer access points.

However, some experts warn that Minimum RSSI can do more harm than good, as it disconnects clients regardless of whether there are other access points nearby. Therefore, it’s important to find a balance and conduct a site survey.

Fast Roaming Protocols 802.11r/k/v

To ensure seamless roaming in modern UniFi networks, it’s recommended to enable fast roaming protocols 802.11r/k/v. These protocols significantly reduce the time to switch between access points from several seconds to milliseconds.

802.11r (Fast Initial Link Setup):

• Allows clients to quickly authenticate to a new access point
• Reduces roaming time to 50-100 ms
• Enabled in SSID settings: Settings → WiFi → SSID Settings → Advanced Settings → 802.11r

802.11k (Radio Resource Measurement):

• Allows access points to exchange information about neighboring access points
• Helps clients make roaming decisions based on real data
• Recommended to enable for environments with high access point density

802.11v (Wireless Network Management):

• Manages client access to the network (BSS Transition Management)
• Allows access points to recommend client transitions
• Works in conjunction with Roaming Assistant

Enabling these protocols is especially important for mobile devices such as laptops and smartphones, which often experience roaming issues without support for modern standards.

Optimizing Access Point Placement and Power

Proper placement and configuration of access point transmit power are critically important for quality roaming. Even with perfect roaming settings, poor coverage planning will prevent clients from switching to closer access points.

Placement recommendations:

1. Even distribution - access points should be positioned so that coverage areas overlap by 15-20%
2. Obstacle removal - avoid placing access points behind thick walls or metal structures
3. Optimal height - for offices, installation height of 2.5-3 meters is recommended
4. Installation angle - direct antennas toward areas where clients are expected to gather

Transmit power configuration:

• For 5 GHz: typically 16-20 dBm for office environments
• For 2.4 GHz: 14-18 dBm (due to larger coverage area)
• Important: Too high power can lead to interference, while too low power can result in coverage gaps

Experts recommend configuring power levels to ensure even coverage without excessive overlap. This will help clients make roaming decisions based on actual signal quality.

Using Roaming Assistant

Roaming Assistant is a feature introduced in UniFi Network version 9.2 that uses BSS (Basic Service Set) Transition Management technology to improve roaming. This feature significantly enhances the performance of modern clients that support 802.11v.

How to configure Roaming Assistant:

1. Go to Settings → WiFi → SSID Settings
2. Find the Roaming Assistant parameter
3. Set the value to Enabled
4. Configure the threshold for roaming recommendation (typically below -70 dBm)

The Roaming Assistant feature works in conjunction with the 802.11v protocol, allowing access points to recommend clients switch to another access point when the current signal becomes weak. This is especially useful for mobile devices that may not always make the correct roaming decisions on their own.

Recommendations for Channels and Coverage Overlap

Proper channel configuration is also important for quality roaming. Incorrect channel settings can lead to interference and degraded connection quality.

Channel recommendations:

1. 5 GHz: Use different channels for each access point
2. 2.4 GHz: When using multiple access points, use channels 1, 6, 11
3. Channel width: For 5 GHz, 40 MHz is recommended; for 2.4 GHz, 20 MHz or 40 MHz

Coverage area overlap:

• Coverage areas of neighboring access points should overlap at the -68 dBm level
• This creates a “transition zone” where a client can smoothly switch to another access point
• Too little overlap can lead to connection loss during roaming

Reddit users recommend using 5 GHz only if there are no legacy devices or IoT devices that can be placed on a separate SSID. It’s also important to remember that all access points should operate on different channels to avoid interference.

Practical Configuration and Testing

After theoretical preparation, let’s look at practical steps for configuring roaming for your network with 3 access points:

Step-by-step configuration:

1. Site survey:

   • Use the UniFi Mobile app to conduct a survey
   • Identify areas with the lowest signal levels
   • Check connection quality in coverage overlap areas

2. Basic settings:

   markdown

   - Minimum RSSI: -70 dBm
   - Minimum Data Rate: Auto (or 5.5 Mbps for 2.4 GHz, 6 Mbps for 5 GHz)
   - Roaming Assistant: Enabled
   - 802.11r/k/v: Enabled
   - Transmit Power: Optimized for even coverage
   

3. Roaming testing:

   • Use an application to measure connection quality (e.g., NetSpot)
   • Walk through the office with a mobile device, tracking handoffs
   • Check speed and connection stability while moving

4. Final configuration:

   • Adjust parameters based on test results
   • Pay special attention to Minimum RSSI values
   • Ensure coverage areas overlap sufficiently

For optimal results, it’s recommended to conduct a site survey to determine the most suitable parameter values for your specific environment.

Sources

1. UniFi WiFi SSID and AP Settings Overview – Ubiquiti Help Center
2. UniFi’s Advanced Wi-Fi Settings Explained — McCann Tech
3. Perfect roaming Wi-Fi setup : r/UNIFI
4. Wi-Fi Roaming UniFi & iPhone & Android - IT Pro Expert
5. Understanding and Implementing Minimum RSSI – Ubiquiti Help Center
6. How UniFi Handles Seamless Roaming : Min-RSSI Band Steering Best Practices
7. UniFi Minimum Data Rate Control: A step by step guide

Conclusion

Configuring roaming parameters on a UniFi controller version 9.5.21 requires a comprehensive approach, including optimizing Minimum RSSI, enabling fast roaming protocols, proper access point placement, and using modern features like Roaming Assistant. To solve the problem of clients staying connected to a distant access point at the entrance, start by setting Minimum RSSI in the range of -70 to -75 dBm and ensure coverage overlap at the -68 dBm level. Always conduct a site survey and testing to achieve optimal results in your specific environment.