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"Bluetooth Low Energy Fundamentals" documentaion corrections

beemavishnu

Hello,

I was going through "Bluetooth Low Energy Fundamentals"
https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/.

I feel few need to be corrected. Please find below points. Correct me if I am wrong.

  • Is this statement correct "To ensure data integrity, all packets transmitted over Bluetooth LE will be retried infinitely until an acknowledgment is received or the connection is terminated."

For new one who is trying to understand Bluetooth, "Infinetely" is a broader word. Better can add a note saying even can configure on how many retries can be done before saying Packet Tx failed.

academy.nordicsemi.com/.../

  • "Connection event: Occurs every connection interval, when the central sends a packet to the peripheral".

But in picture Connection even is marked from CTx -> PRx. But even PTx -> CRx will also be part of connection event.

As per "Figure 1.3: Connection events" from BT SIG, even P->C is considered as part of connection event. Also if there are back to back data exchange between C->P & P->C withing connection interval, even those are considered within same "connection event".

https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-61/out/en/architecture,-change-history,-and-conventions/architecture.html#UUID-3ca385af-187d-8221-1114-504a7b3c6091

- "During bonding, they can also exchange and store identity keys so they can recognize each other for future connections through the random resolvable private address."

This statement is misleading. "random resolvable private address." is not used during bonding and its required for Private address but not Public address devices.

academy.nordicsemi.com/.../

Thanks & Regards

Vishnu Beema

Parents
  • +1

    Hi Vishnu Beema,

     

    • Is this statement correct "To ensure data integrity, all packets transmitted over Bluetooth LE will be retried infinitely until an acknowledgment is received or the connection is terminated."

    For new one who is trying to understand Bluetooth, "Infinetely" is a broader word. Better can add a note saying even can configure on how many retries can be done before saying Packet Tx failed.

    I agree that "infinitely" can be dropped from the sentence - however; the sentence this holds truth.

    The link will keep re-transmitting until either an ACK is received or the supervision timeout is exceeded; thus disconnecting the link.

     

    I will give feedback to our dev academy team.

    But in picture Connection even is marked from CTx -> PRx. But even PTx -> CRx will also be part of connection event.

    There are arrows between central and peripheral. Meaning that you will be able to exchange data from C->P or P->C.

     

    However; the protocol dictates who transmits initially and who is in receive mode initially.

    This is what the figure is trying to show at the start of a connection interval.

    This statement is misleading. "random resolvable private address." is not used during bonding and its required for Private address but not Public address devices.

    I do not see how this is misleading, as it is a valid bluetooth address type. The description is trying to cast a wider net, to include information how the different bluetooth address types are handled.

    I would recommend that you look at this blog post from novelbits, as there is a more in-depth explanation related to bluetooth address types and privacy available here:

    https://novelbits.io/bluetooth-address-privacy-ble/ 

     

    Kind regards,

    Håkon

Reply
  • +1

    Hi Vishnu Beema,

     

    • Is this statement correct "To ensure data integrity, all packets transmitted over Bluetooth LE will be retried infinitely until an acknowledgment is received or the connection is terminated."

    For new one who is trying to understand Bluetooth, "Infinetely" is a broader word. Better can add a note saying even can configure on how many retries can be done before saying Packet Tx failed.

    I agree that "infinitely" can be dropped from the sentence - however; the sentence this holds truth.

    The link will keep re-transmitting until either an ACK is received or the supervision timeout is exceeded; thus disconnecting the link.

     

    I will give feedback to our dev academy team.

    But in picture Connection even is marked from CTx -> PRx. But even PTx -> CRx will also be part of connection event.

    There are arrows between central and peripheral. Meaning that you will be able to exchange data from C->P or P->C.

     

    However; the protocol dictates who transmits initially and who is in receive mode initially.

    This is what the figure is trying to show at the start of a connection interval.

    This statement is misleading. "random resolvable private address." is not used during bonding and its required for Private address but not Public address devices.

    I do not see how this is misleading, as it is a valid bluetooth address type. The description is trying to cast a wider net, to include information how the different bluetooth address types are handled.

    I would recommend that you look at this blog post from novelbits, as there is a more in-depth explanation related to bluetooth address types and privacy available here:

    https://novelbits.io/bluetooth-address-privacy-ble/ 

     

    Kind regards,

    Håkon

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