Throughput ATT_MTU

[Ridhi]

We are using nrf52832 soc for our product development and using that we are trying to increase the throughput of our device using the information from the following forum:
Novel Bits throughput guide 
In this forum it states that the Maximum GATT MTU SIZE possible is 247 bytes in which 244 bytes of data is the actual payload size and if the data is greater than the limit, then it will split into multiple packets. So we tried to send more that 247 bytes of data just to check how the data split in multiple packet is working. We tried to sent 256 bytes of data and we were able to get 255 bytes of data without any splitting, which is more than 247 bytes. So we are wondering what is the Maximum GATT MTU SIZE possible in nrf52832 soc. 
We also looked into the throughput example provided by the nordic (ble_app_att_mtu) and in that MTU size is set to 247 and data length is set to 251 which is less that what we are able to send from nrf52832 to phone, is there any possible explanation for this?

[Ridhi]

i have used att throughput example but i have to test throughput for my own application as my task is to compare between PHYs LE 1m and Le 2m. Pls give me a suggestive way and help as earliest Simonr

[Simonr]

Hi

Yes, but I would think it is easiest to only change the PHY in the throughput example in order to compare the two PHYs, as either something in your application or on the phone side seems to be setting the window size larger in one setting or the other. I guess you can try editing the scan window settings in your application.

Best regards,

Simon

[Ridhi]

how can i use throughput example for my project

Like my aim is to compare PHYs LE 1M and LE 2 M for my project in which

I take 2000 logs for data length is 12 bytes

I set Att_MTU as 247 and Gap Legth as 251

How shall i estimate throughput and check it using sniffer because from traces i had shared you my project works fine for LE 1M but for LE 2M it is taking much time

[Simonr]

Hi

The ATT_MTU throughput example is made exactly for this purpose. To show how different connection parameters influence the throughput performance of BLE connections.

Testing the example application requires two boards, which are both programmed with the same application. One of the boards must be connected to the computer and will serve as the tester. The other board responds to the requests that are sent by the tester. A menu is printed on UART. Through the menu, you can choose to run the test or configure the connection parameters. During the test, the boards connect with the given parameters. The tester then sends 1 MB of data. After that, it queries how much data was received by the other board. Please take the time to read through the example's setup and testing section on the Infocenter.

Best regards,

Simon

[Ridhi]

Hello Simonr,

I have taken 10k logs for a data  which was 12 bytes .

i have ci set as 400 ms

i tested it for Le 2m and Le 1m

i am able to receive data in LE 2m in lesser times as compared to Le 1m.

My concern is now that which PHY ie LE 1m or Le 2m consumes much power sending same amount of data?

This is trace when LE 1m phy is enabled

This trace is when le 2m phy is enabled