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Connection parameters: nRF Connect & finding them in Wireshark

Vala

Hi,

Could someone help me about the following questions?

Q1: What are the connection parameters set by the Android app nRF Connect? Can I change them?

Q2: How can I find out about these parameters via nRF Sniffer, more specifically, the connection interval? I know that the final decision is made by the Central (Initiator) and is reported in CONNECT_REQ packet. Does this packet contain the final settings? What types of packets should I look for to understand what the final connection interval is?

Q3: Can delta time parameter in the Wireshark be used to find the connection interval? Please see the attached images. In this connection, the CONNECT_REQ showed that the connection interval is 50 ms. Although, the delta time for the Rcvd Handle Value Notification, which I assume is the packet that contains the data (I recognized some the bytes that the Peripheral sent), shows a value of 150 us and 382 us for end to start and start to start parameters, respectively. On the other hand, there are some Empty Data PDUs that show a value of ~47000 us for these parameters, which makes sense according to the connection parameters set in the CONNECT_REQ packet. Is there anything that I don't understand correctly? Can the delta time parameters be used to find out about connection interval?

The Rcvd Handle Value Notification packet: image description

The Empty Data PDU packet: image description

-Vala

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    @Vala: 2. All the transmissions in one connection event is sent in one channel. The channel is changed on every connection event. This is called channel hopping.

    The delta time only tell the distance between a packet and the next one. It's not necessary represent the connection interval. The reason is that there are more than one packet per connection event. At least 2 one from master one from slave, there could be more (typical 6 from each side) if the peer has more data to send. The distance between them can be very short, as you already found. When there is nothing to send, only 2 packets per connection event, and you can see the delta time close to the connection interval.

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    @Vala: 2. All the transmissions in one connection event is sent in one channel. The channel is changed on every connection event. This is called channel hopping.

    The delta time only tell the distance between a packet and the next one. It's not necessary represent the connection interval. The reason is that there are more than one packet per connection event. At least 2 one from master one from slave, there could be more (typical 6 from each side) if the peer has more data to send. The distance between them can be very short, as you already found. When there is nothing to send, only 2 packets per connection event, and you can see the delta time close to the connection interval.

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