Re: Instable BLE connection - MTU Request, Attribute not found

Hi,

Den mån 26 juli 2021 kl 18:19 skrev Peter Höller [off-list ref]:

Hi Emil!

Thanks for your input!!

I do have to stabilze this connection, I do not have any other chance,
unfortunately.

What I fell in my guts right now is that most likely:
 this >>>>
2. The peripheral could use white listing to allow connections from
only specific centrals. In this case the central will always see a
connection complete immediately followed by a connection failed to be
established.

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and this>>>>>
If the peripheral
responds at least once, but after that at any time it doesn't respond
to a central's packet within the set supervision timeout, the
"Connection Timeout" disconnect reason will happen.

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plays a role in my issue!!

However , just to be mentioned, I cannot set (or prolong) supervision
timeout period, which was my intention initially.

here is what I am able to read/set (sudo nano) under:
root@odroid:/sys/kernel/debug/bluetooth/hci0#

6lowpan                     force_sc_support         random_address
adv_channel_map             force_static_address     rpa_timeout
auto_accept_delay           hci_revision             sc_only_mode
blacklist                   hci_version              sniff_max_interval
conn_info_max_age           identity                 sniff_min_interval
conn_info_min_age           identity_resolving_keys  ssp_debug_mode
conn_max_interval           idle_timeout             static_address
conn_min_interval           inquiry_cache            uuids
dev_class                   le_auto_conn             voice_setting
discov_interleaved_timeout  link_keys                white_list
dut_mode                    long_term_keys           white_list_size
features                    manufacturer

Do you have any suggestions for those parameters or am I tuning on the
wrong place here?

However, I am going for wireshark fur ubuntu now, if I understood you right?

with kind regards

Peter

Someone else should reply to the question about modifying the
supervision timeout. I think BlueZ hardcodes it but I might be wrong.
Either way you could always locate the code for it and recompile with
new parameters.

For a BLE sniffer you could for example use an nRF52 devkit, flash the
sniffer firmware at
https://www.nordicsemi.com/Products/Development-tools/nrf-sniffer-for-bluetooth-le
and then use Wireshark to analyze the traffic in real time.

/Emil