Light Switch Demo. Relaying messages, relayed messages TTL limited to 4.

[VadymS]

Hi. I try to run example Light Switch Demo.

I use: Mesh SDK v.2.2.0. NRF SDK v 15.0.0. Softdevice: s132_nrf52_6.0.0.

I see that relayed messages have maximum TTL = 4, when i send with initial value 10.

I have 8 boards. Boards are placed in line, when every board placed in communication distance between 2 another. First is Switch(client) and other Servers (Lights). I see, that the last one receives command with probability ~60-70%. I used TTL = 10.
When I try to run the server example from debugger, I see, that the first message I receive with TTL = 9 (initial value is 10) and another, retransmitted with maximum value 4. Even when I use only 3 boards (switch + 2 servers), in one of the debugging server I get 2 messages: one with TTL = 9 and second with TTL 4.

Is there some limitation or dependence of TTL from some factor?

[Hung Bui]

Hi Vadym, 

Could you check the value of ACCESS_DEFAULT_TTL, TRANSPORT_SAR_SEGACK_TTL_DEFAULT and NRF_MESH_TTL_MAX in your code? 

TTL = 4 when you have initial TTL = 10 meaning it went through 6 hops , this doesn't make much sense in your setup. 

And could you verify those message with TTL = 4 actually are valid message ? A packet that already forwarded should not be forwarded again. 

If you set your original message to TTL = 6 and then 3 for example, what would be the result ?