packets per connection interval from nRf sniffer log

[Nivetha]

Hi!

Thanks for this post blog and question on sniffer logs. However, I am not clear on how to calculate the number of packets sent every connection interval? Please clarify.

In my case, the connection interval is 10ms and I transmit the following data

• Battery status every 1 sec
• Temperature status every 1 sec
• Dummy data 10 samples/10ms

Please find the sniffer log in this link sniffer log

1. How to determine the number of packets transmitted per connection interval?
2. How to differentiate between the temperature/battery notification vs dummy data notification?

Thanks, Nivetha

[endnode]

1. Connection interval is extended by More Data (MD) bit in LL PDU header. See slides 115, 122 and 123 here. So by looking at MD bits and time-stamps you need to count it yourself. Yes, time-stamps on Nordic sniffer with Wireshark aren't very accurate, that's what you get for $40, anything better costs you $1k-$30k (depending on brand and other capabilities).
2. Only you know what data are going over your link so it's only you to tell which data are which. If you use different GATT Services/Characteristics to transport these then it is easy but even with single GATT "tube" it should be trivial to define some reasonable protocol how to decode data transported over.