CYW43455 paring problem using MTU greater than 23

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niazofb
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First reply posted First question asked Welcome!

Hi,

I am trying to pair (LE Secure) device with MTU greater than 23 but the links disconnects with timout.

pairing with MTU = 23 works without problems.

I am using the Raspberry-pie with blueZ version 5.50.

please help.

thanks.

 

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Zhengbao_Zhang
Moderator
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250 sign-ins First comment on KBA 10 questions asked

Hello:

   Would you please help to capture one sniffer for confirm?

I think the question is caused by below two limitations:

1.  the MTU size is limited by host stack setting like Bluez .

2.  The MTU size is limited by the ble profile version since "LE Data Length Extension" is supported from BLE 4.2 .   it is needed to be checked from the sniffer log.

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niazofb
Level 1
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First reply posted First question asked Welcome!

Hi,

here is the sniffer output with wireshark.

 

thanks,

Ben.

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Zhengbao_Zhang
Moderator
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250 sign-ins First comment on KBA 10 questions asked

Hello:

    I can't see the MTU exchange request from the log and 

by the way I captured some info from spec,   43455 supports 4.1 as default,  

From spec define  larger MTU size is supported from core 4.2 .  

if you can get a LE LLCP version exchange packet from sniffer , it will give a clear answer. 

Zhengbao_Zhang_0-1618219504375.png

 

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