concurrent connections parameters

[Davide]

Hello, I'm working on a concurrent role device (advertiser+scanner+peripheral+central) and devices are configured to connect each other in a mesh-like way (Note: I'm not using BLE MESH!). I noticed that the connection events seems to be skipped when more than one link is present. All devices are configured to use 20ms. Once the first link is created with the DUT, the link uses 20ms as connection interval, but when the second link is created it seems that the DUT bounces on the two links, serving them with an actual connection interval of 40ms.

Is it normal?

[Petter Myhre]

It could be normal. It depends a bit on what kind connection you have. If you have peripheral connections (as a central) you shouldn't have many dropped connection events if you have selected your connection interval correctly, see the Suggested intervals and windows Section in the SoftDevice specification. This is because the central dictates when the first connection event is (and all others), and it can schedule them one after another. As a peripheral it is the peer (central) that dictates this, so then you could have conflicts.

[Davide]

Yep, that's what I expected. Anyway I'm focusing on the central side of the link and I saw some strange behavior in multirole (for instance, the scanner was activated just a faction of the 'free' time of the radio). I found useful to change NRF_SDH_BLE_GAP_EVENT_LENGTH parameter to a low value (I'm not transferring data, but just keeping the link!)