Chained Advertisement

RE: Chained Advertisement

Olivier Balitch — Wed, 26 Sep 2018 15:04:40 GMT

Hi Mihir,

Thanks for your answer. I got the answer on another thread:

https://devzone.nordicsemi.com/f/nordic-q-a/38702/maximum-extended-advertising-data-length-supported

Nordic confirmed that the maximum advertising data length from host to link layer is 255 bytes. Their advertising chain can contain up to 255 bytes.

Best regards,

Olivier

RE: Chained Advertisement

Mihir Tailor — Sat, 22 Sep 2018 05:15:46 GMT

This link help you to understand further.

Kindly see Extended Advertisements Section in this link

https://blog.nordicsemi.com/getconnected/bluetooth-5-advertising-extensions

RE: Chained Advertisement

Mihir Tailor — Sat, 22 Sep 2018 05:09:28 GMT

Hi Olivier....
I think you are talking about the following lines under the section 2.3.4.9 Host Advertising Data
The total amount of Host Advertising Data before fragmentation shall not exceed 1650 octets.
You may be misunderstood this line.
Actually BLE stack is divided into two parts: 1. Host and 2. Controller
Here, Host Advertising Data means the Data sending from the Host to the Controller
So, before the fragmentation by the link layer, the maximum data size sent by the Host to the Controller is 1650 octets.

So, Link Layer receives the Maximum Host Advertising Data of 1650 Bytes at a time.
But Link Layer can send only 255 bytes of Advertisement Data in single packet. So it can fragment the Data received from the Host if Received Data is greater than 255 Bytes.

Other point that I want to mention is that the size of bytes that Host can send to the Controller is greater than 1650 than L2CAP Layer in the Host fragments that data and send the only maximum size of 1650 bytes to the Controller.

I hope this explanation helps you to solve your query.

Have a Nice Day...

RE: Chained Advertisement

run_ar — Fri, 21 Sep 2018 13:12:52 GMT

For reference: https://devzone.nordicsemi.com/f/nordic-q-a/38702/maximum-extended-advertising-data-length-supported

RE: Chained Advertisement

Olivier Balitch — Fri, 14 Sep 2018 08:26:46 GMT

Hello,

I have same setup (PCA10040 deb board with nRF52832, Softdevice 6.1.0 & SDK 15.1.0). I wanted to use the extended advertisement feature to advertise more than 255 bytes of data.

Looking to the release note, Nordic claim they support chained advertisement but in ble_gap.h header file, I see BLE_GAP_ADV_SET_DATA_SIZE_EXTENDED_MAX_SUPPORTED = 255.

The BLE specification mentions that up to 1650 bytes could be sent in an extended advertisement. Maybe Nordic supports a limited number of chained packets but then the define in ble_gap.h does not match.

@Mihir: Did you manage to do some extended advertisement with data length > 255?

@Nordic support: Can you please help?

Thanks

RE: Chained Advertisement

Mihir Tailor — Sat, 08 Sep 2018 12:15:46 GMT

In the ble_advdata.c file, there is an instruction like this if (((*p_offset) + AD_DATA_OFFSET + data_size) > max_size)
    {
        return NRF_ERROR_DATA_SIZE;
    }

inside the sections of encoding of each advertising data. So based upon this, we can say that if we send more than max allowed size, it will return an error of Data Size exceeds than specified. So here we cant perform Chained Advertisement.

Kindly suggest the solution to do Chained Advertisement on the platform having PCA10040, S132 v6.1.0 & SDK 15.1.0

RE: Chained Advertisement

run_ar — Mon, 27 Aug 2018 18:57:47 GMT

Hi,

As far as I can see the advertisement module supports packet of a length up to: BLE_GAP_ADV_SET_DATA_SIZE_EXTENDED_CONNECTABLE_MAX_SUPPORTED (238).

If you look at the Softdevice release notes you can see that; The SoftDevice is now able to send chained advertisements. The advertising data fragmentation is handled autonomously by the SoftDevice. This means you do not have to worry about chained advertisements in your application.