mesh Configuration

RE: mesh Configuration

Hung Bui — Tue, 09 Apr 2019 12:13:12 GMT

Okey, my understanding is that you will not relay those message with very low RSSI to avoid network traffic. This is fine but it will reduce the redundancy capability of the network.

To do this you can have a look at network_packet_in() inside network.c, you can find RSSI inside p_rx_metadata->scanner.rssi. Then you can choose to do packet_relay() or not.

RE: mesh Configuration

MK Chen — Mon, 08 Apr 2019 11:02:51 GMT

the purpose of adding RSSI filtering is to filter signal beyond adjacent relay note, to verify performance of BLE-Mesh relay feature.

RE: mesh Configuration

Hung Bui — Mon, 08 Apr 2019 09:12:53 GMT

If you setting up using the mobile app (I'm testing on Android) you can find the TTL setting when configuration the publication setting of the Generic OnOff server.

You can also configure the number of retransmission on the network layer in the same window.

3. I don't think adding access layer RSSI filtering would help here.

RE: mesh Configuration

MK Chen — Fri, 05 Apr 2019 14:18:28 GMT

using nRF Mesh mobile app.

Would you mind to provide more detail:

1 how to get TTL value in light switch server mode?

2 how to get APP_UNACK_MSG_REPEAT_COUNT in light switch server mode?

3 where should be added RSSI filter at access layer?

Appreciate your help. Thnaks

RE: mesh Configuration

Hung Bui — Fri, 05 Apr 2019 11:05:38 GMT

How do you provision your mesh network ?

RE: mesh Configuration

MK Chen — Fri, 05 Apr 2019 01:49:51 GMT

Dear Hung Bui,

I checked node_setup.c, but this file is not inside project, so current light switch is not this method to get TTL?

Thanks

MK Chen

RE: mesh Configuration

MK Chen — Thu, 04 Apr 2019 15:32:47 GMT

Sniffer capture.

RE: mesh Configuration

Hung Bui — Thu, 04 Apr 2019 15:21:57 GMT

You can find APP_UNACK_MSG_REPEAT_COUNT = 2 in our lightswitch client code (SDK v3.x)

It's very simple we call access_model_publish() APP_UNACK_MSG_REPEAT_COUNT times when we send one message.

The TTL value is set during provisioning&configuration , you can find it in the node_setup.c at client_pub_state_set() or config_step_execute() at NODE_SETUP_CONFIG_PUBLICATION_ONOFF_SERVER event.

Node that it's only for the light switch example. If you write your own code and your own provisioner, you may set it differently.

RE: mesh Configuration

MK Chen — Thu, 04 Apr 2019 14:39:34 GMT

Hi Hung Bui, Thanks for you reply.

my setup as following diagram:

may

I don't think there is many interference, because it is office and after office hours. Since Tx power is -16dBm, I may be too low. my idea is increase Tx to -10 dBm and add RSSI filter to prevent Tx signal bypass reply note.

I have used sniffer to capture Relay signal, normally it will be relay 3 packets at 37,38 and 39, but sometimes less then 3 packets, is it should be sniffer missed packets?

Could I consult you following:

what is default TTL value? where can check at source code ?

I can't find APP_UNACK_MSG_REPEAT_COUNT = 2 , where can check repeat number at source code?

Thanks

MK Chen

RE: mesh Configuration

Hung Bui — Thu, 04 Apr 2019 12:54:05 GMT

You can find the rssi value inside nrf_mesh_rx_metadata_t ->scanner->rssi.

But I don't see how rssi having rssi filter here can help.

PROV_BEARER_ADV_UNACKED_REPEAT_COUNT is not related, as it's for provisioning bearer

How far is it between your relays ? Do you have a lot of interference ? I don't see how success rate with one hop is 90% then with 2 hops it's only 50% Thought it should be around 81%.

Please make sure you have good enough TTL to cover all the hops. In your case TTL should be minimum 4.

What is the repeat number you find in the sniffer ? Could you show ?

RE: mesh Configuration

MK Chen — Thu, 04 Apr 2019 03:57:39 GMT

repeat number what I saw using Sniffer is 3. Is it following #define?

#define PROV_BEARER_ADV_UNACKED_REPEAT_COUNT (4)

RE: mesh Configuration

MK Chen — Thu, 04 Apr 2019 03:28:11 GMT

Could you provide more detail instruction of filtering RSSI , which file and which function ?

Thanks a lot.

RE: mesh Configuration

MK Chen — Thu, 04 Apr 2019 03:24:54 GMT

directly without relay: successful rate is 100%

one hop relay: successful rate is 90%

two hop relay: successful rate is 50%

RE: mesh Configuration

Hung Bui — Wed, 03 Apr 2019 16:30:12 GMT

Hi Chen,

What is the success rate do you have ?

Do you have any retransmission for a packet you send ? In our example (light_switch) we have APP_UNACK_MSG_REPEAT_COUNT = 2

Changing BEARER_SCAN_INT_DEFAULT_MS and BEARER_SCAN_WINDOW_DEFAULT_MS wouldn't help since we already scanning at 100%

Regarding RSSI filtering, you can filter after the message arrived in access layer, but not in the radio or in network layer.

RE: mesh Configuration

MK Chen — Wed, 03 Apr 2019 12:02:18 GMT

Could I add one more inquiry:

how to adjust up threshold of RSSI level to filter out signal < -60 dBm ?

Thanks