Two communication methods of BLE module

Before the connection is established, the BLE devices can communicate by broadcasting and scanning. Once the connection is established, the two parties can communicate through the client/server mode (a link layer connection is established). Therefore, for the BLE network, there are two communication methods. Mode: Broadcast Communication Mode and Connection Communication Mode.

Broadcast Communication Mode

1. It is a connectionless approach

2. It is one-way and can send data to any person or receiver.

3. The role of participation is Broadcasting and Observing

4. Broadcast communication is to communicate through broadcast and scan response,

5. Is a connectionless way to send data to any scanning device or receiver

6. There are no security measures for using broadcast communication, any listening device can receive it, so it may not be suitable for sensitive data. unless some encryption method is used in the broadcast data

7. Broadcast packets and scan response packets include a maximum payload of 31 bytes (BLE 5.0 adds broadcast capabilities), so using broadcast communication, the maximum data can only be 62 bytes (advertisement and scan response), the transmitted Information is limited by that size

8. On the other hand, if both parties only want to transmit a small amount of data or to transmit information to multiple devices around, using broadcasting is a convenient option. Such as Apple's iBeacon, Google's Eddystone beacon, positioning based on BLE broadcast, etc.

Connection Communication Mode

In essence, the connection is only the way that the data can be exchanged between two devices and the representation of the data is different. With the connection, the content of the data transmission is richer, such as encrypted data. The two sides of the device establish a permanent connection, and periodically exchange data between the two devices, and the data content is diverse.

The participants are the master and the slave. After the connection is established, the two devices can communicate periodically (connection events). The data transmission and reception of the two devices are independent, and their roles do not affect the data throughput. Or the priority is limited, from the perspective of data communication, the two are independent.

A device may be both central and Peripheral

A central can connect multiple Peripheral based connections to expand a richer network topology.

One Peripheral can connect to multiple centrals, and now HYXKIOT's BLE 5.1 module HY-TB01B supports multiple connections.