Multi-Connection Guide
Introduction
The following table provides an overview of the maximum number of concurrent connections supported for each ESP Bluetooth LE Host. In multi-connection scenarios, connection parameters must be configured appropriately. In general, as the number of connections increases, the connection interval should be increased accordingly. For detailed parameter configuration recommendations and SDK configuration details, please refer to the corresponding example code in the following table.
In this document, the maximum number of connections refers to the maximum number of simultaneous active connections that the device can maintain, whether operating as a central or peripheral.
Host SDKconfig
Host |
Max Connections |
SDKconfig |
Example |
|---|---|---|---|
ESP-Bluedroid |
9 |
||
ESP-NimBLE |
9 |
Controller SDKconfig
The configuration option BT_CTRL_BLE_MAX_ACT defines the maximum number of Bluetooth LE activities that the controller can handle simultaneously. Each Bluetooth LE activity consumes one resource, including:
Connections
Advertising
Scanning
Periodic sync
Therefore, this parameter should be configured as follows:
Maximum connections + required advertising, scanning and periodic sync instances
Example: If the Host supports up to 8 connections, and the application requires 1 advertising instance and 1 scanning instance concurrently, set BT_CTRL_BLE_MAX_ACT to 10 (8 + 1 + 1).
Note
The ability to support multiple connections highly depends on the application’s overall memory usage. It is recommended to disable unnecessary features to optimize multi-connection performance.
When the device operates in the peripheral role, connection stability and overall performance will be influenced by the central device and the negotiated connection parameters.