What is the Maximum packet size to send data over bluetooth in Android?

Question

I'm working on an Android Bluetooth project to send and receive data from a custom made hardware. I used Bluetooth Chat Sample in SDK as basis.

I am sending data from one device to another (LG Nexus 4). All is ok until I reach a length of 1004 bytes (it is the audio data). At that point it splits it into 2 messages of 990 and 14 bytes in most of cases. but is strange sometimes its sending 1004 without splitting (approx. 4 times in 100).

I am sending this packet of 1004 bytes, in which there is 4 bytes is my header and rest of 1000 bytes is actual data which I want to use as per command in header, now if packets are splitting as per above mentioned way than I cannot handle the flow.

So, please let me know why packets are splitting in such way and how can I stop this splitting or, if I cannot do this, than please suggest me any alternative way to do this.

Thanks.

Answer 1

Data sent via Bluetooth socket is abstracted as a stream. Here the transport layer is broken into packets, where packet has a maximum size of almost 1KB(1000 bytes). So you can devise a mechanism in which you can send the message length info in the header, then on receiving side you will have to make subsequent read() calls; each returning data for one packet.