How to speed up connection and database discovery.

RE: How to speed up connection and database discovery.

Simonr — Mon, 28 Mar 2022 12:52:52 GMT

I'm not sure I understand the question, but I think you should be able to store multiple "peer datas" and load the one you plan to use as needed if that's what you're asking.

Best regards,

Simon

RE: How to speed up connection and database discovery.

AlessandroADG — Fri, 25 Mar 2022 16:19:39 GMT

Hi,

I will try to implement it.
Only one question looking to the code.

The example is referred to a single link.

I am on a central multilink.

Do you think pm_peer_data_remote_db_store() and pm_peer_data_remote_db_load() work only with peer database array?

Alessandro

RE: How to speed up connection and database discovery.

Simonr — Mon, 21 Mar 2022 13:56:32 GMT

Indeed, the peer manager supports storing the remote database on the central side. Typically, it's used so that the database is stored once service discovery is completed when handling the NRF_BLE_GATTS_C_EVT_DISCOVERY_COMPLETE event by calling pm_peer_data_remote_db_store().

So when connecting to an already bonded peer at a later point the database is restored by a call to pm_peer_data_remote_db_load(). The GATT service client example does this already for example.

Best regards,

Simon

RE: How to speed up connection and database discovery.

AlessandroADG — Sat, 19 Mar 2022 08:08:58 GMT

Hi Simon,

I read something about Database discovery module (not so detailed documentation) but solution 1 and 2 bring me to the same oubt.

You wrote:

service discovery is necessary to ensure that the client interacts with the servers characteristics using the correct attributes handles

I know in advance the server characteristic or I can store and recover them with Peer Manager, fine.
But how I can link characteristic with handles?

On the pheripheral (server) I have:

sd_ble_gatts_service_add() and sd_ble_gatts_characteristic_add()

I have found to similar function for the client.

So, how to establish connection after the database restore?

Note: searching in the forum I have found this thread Can BTLE communication happen without service discovery?

They have our similar issue: database discovery taking 1.5s also with 7.5ms of connection interval.
I guess I have to investigate about this.
Do you have any suggestion about it?

Alessandro

RE: How to speed up connection and database discovery.

Simonr — Fri, 18 Mar 2022 14:50:58 GMT

Hi Alessandro

1. Indeed, the application has control over when it wants to do a service discovery. If you store the handles of the characteristics together with the peer address after a service discovery they should be stored. I don't think we have an example doing this unfortunately. But reading the usage page on the Database discovery module and Peer Manager should be helpful.

2. No, service discovery is necessary to ensure that the client interacts with the servers characteristics using the correct attributes handles. Service discovery is also important because Bluetooth LE advertising does not mandate that all services are advertised.

Best regards,

Simon