AX200/201 BLE data length extension not expected behavior (incorrect time)

[KostasS]

Hello,

I am using 2 laptops one with an AX200 and the other with an AX201 adapter. The laptop is used as a master and a custom board (BLE 5.0) as a slave in BLE connection.

I am facing the following problem:

As observed using a BLE sniffer on wireshark, when the board is connected to a laptop using the AX200/201 the custom board initiates a LL_LENGTH_REQ with the following parameters:

Max RX octets: 140

Max RX time: 2000 microseconds

Max TX octets: 140

Max TX time: 2000 microseconds

And gets an LL_LENGTH_RSP from the master with the following

Max RX octets: 251

Max RX time: 328 microseconds

Max TX octets: 251

Max TX time: 9101 microseconds

Even if the request is for 251 octets/2120usec, the response still has the Max RX time fixed to 328 microseconds, which is not adequate for sending 251 bytes. As a result the packets are then split in 27/67 bytes long fragments (for 1mbps/2mbps PHY respectively) which affects both the connection speed and stability.

I have done the same tests using a BLE dongle or my mobile phone as master and the result is the expected

Max RX octets: 251

Max RX time: 2120 microseconds

Max TX octets: 251

Max TX time: 2120 microseconds

This looks a lot like this issue on the AX 9260 adapter

AC 9260 BLE data length extension problem

Having the AX200 perform as expected is very important, since it is the one shipped with the laptops we are using for testing our hardware.

The above results were the same when tested with the latest 22.150.0 driver.

On AX200 I randomly get the correct connection parameters but this happens every 1 in 10 or more attempts. On the AX201 I never get the correct RX time.

Could you please let me know why this is happening?

Thanks!

PS: Some additional info,

- Results were the same on Windows 10 and Windows 11

- The above measurements are done using wireshark on an NRF Dongle

- The custom board is based on nrf52840, running the s140 softdevice stack

- The laptops used for testing were Microsoft Surface Go 2/3 (AX200) and HP Probooks 450 G8 on i5 and i7 CPUs (AX201) with same result.

[DeividA_Intel]

Hello KostasS,  

I was checking your thread and see that we have not heard back from you.  

I’m going to close your post, but if you need further assistance, please do not hesitate to create a new thread. 

Regards,  

Deivid A.  

Intel Customer Support Technician  

[DeividA_Intel]

Hello KostasS, 

Thanks for all the information provided. I would like to inform you that you will receive the NDA via email. 

Please let me know as soon as you sign it.

Best regards, 

Deivid A.  

Intel Customer Support Technician 

[DeividA_Intel]

Hello KostasS,  

After checking your thread, I would like to know if you have signed the NDA.

If so, please let me know. 

Regards,  

Deivid A.  

Intel Customer Support Technician