[NRF 52833] [Bluetooth Mesh] Mising message when hops between node

RE: [NRF 52833] [Bluetooth Mesh] Mising message when hops between node

Hieu — Tue, 03 Jan 2023 13:42:43 GMT

[quote user="Tien_Nguyen"]

Only one node in Group 1 and only one node in Group 2 serve as a relay

>In my case the number of devices is unpredictable, so every device must be a relay.

[/quote]

Please check this case regardless. This is to rule out whether or not your devices in Group 1 or Group 2 are congesting the network with too many redundant retransmissions.

[quote user="Tien_Nguyen"]How will [decreasing TTL] affect the success %, please explain to me. Because if you increase the number of hops to extend the distance, reducing the TTL in my opinion is not suitable[/quote]

In the network you described, even the Server and Client should be in range of each other (10+7+7), so a TTL of 7 seems much too high.

However, I made that recommendation while forgetting that a Mesh node does not relay the same message more than once. That feature ensures that a too big TTL value will not burden the network too much. Thus, your high TTL should not be the main cause of your low success rate.

Sorry for this.

[quote user="Tien_Nguyen"]

Network Transmit Count and Interval

Relay Retransmit Count and Interval

Segment retransmission configurations

If you use periodic publishing, Publish Period, Publication Interval and Publication Retransmission

Message size

>Default by example

[/quote]

To be sure, is it this sample? Bluetooth: Mesh sensor — nRF Connect SDK 2.0.0 documentation (nordicsemi.com)

RE: [NRF 52833] [Bluetooth Mesh] Mising message when hops between node

Tien_Nguyen — Tue, 03 Jan 2023 02:45:38 GMT

[quote userid="9456" url="~/f/nordic-q-a/95253/nrf-52833-bluetooth-mesh-mising-message-when-hops-between-node/402807"]Only one node in Group 1 and only one node in Group 2 serve as a relay[/quote]

>In my case the number of devices is unpredictable, so every device must be a relay.

[quote userid="9456" url="~/f/nordic-q-a/95253/nrf-52833-bluetooth-mesh-mising-message-when-hops-between-node/402807"]Test with a message that is not only relay by Group 1 and Group 2 node, but also received by Group 1 and Group 2, and see what the success rate in Group 1 and Group 2 is.[/quote]

>I'm trying this option

[quote userid="9456" url="~/f/nordic-q-a/95253/nrf-52833-bluetooth-mesh-mising-message-when-hops-between-node/402807"]Decrease TTL to 5[/quote]

>How will this affect the success %, please explain to me. Because if you increase the number of hops to extend the distance, reducing the TTL in my opinion is not suitable

[quote userid="9456" url="~/f/nordic-q-a/95253/nrf-52833-bluetooth-mesh-mising-message-when-hops-between-node/402807"]

Network Transmit Count and Interval
Relay Retransmit Count and Interval
Segment retransmission configurations
If you use periodic publishing, Publish Period, Publication Interval and Publication Retransmission
Message size

[/quote]

>Default by example

[quote userid="9456" url="~/f/nordic-q-a/95253/nrf-52833-bluetooth-mesh-mising-message-when-hops-between-node/402807"]How many nodes are there in Group 1 and in Group 2?[/quote]

>For now the number will be 3, but like I said, the number in each group is unpredictable, it will be random in range 1-3.

[quote userid="9456" url="~/f/nordic-q-a/95253/nrf-52833-bluetooth-mesh-mising-message-when-hops-between-node/402807"]Also, are your message going from Server to Client, or the opposite, or both?[/quote]

I only do it from Server to Client

RE: [NRF 52833] [Bluetooth Mesh] Mising message when hops between node

Hieu — Mon, 02 Jan 2023 12:21:55 GMT

Hi Tien,

Are all nodes in Group 1 and Group 2 relays?

My first guess is that perhaps the network is congested in Group 1 and Group 2, where the nodes are too close, and all relay the same messages at around the same time.

Could you try these tests individually, and let me know what the success rate is like:

Only one node in Group 1 and only one node in Group 2 serve as a relay
Test with a message that is not only relay by Group 1 and Group 2 node, but also received by Group 1 and Group 2, and see what the success rate in Group 1 and Group 2 is.
Decrease TTL to 5

Please also provide a little more information about your network:

Network Transmit Count and Interval
Relay Retransmit Count and Interval
Segment retransmission configurations
If you use periodic publishing, Publish Period, Publication Interval and Publication Retransmission
Message size
How many nodes are there in Group 1 and in Group 2?

Also, are your message going from Server to Client, or the opposite, or both? Your written description contrast with your image a little. This is not important though, since your setup looks same going from both ends to the other.

Hieu