Conflicts with neighbour's gateways ?

[ricorico94]

Hi,
A neighbour is about to build its own MySensors network.. and I already have mine.. Reading the main documenttation, I can't understand if there's a risk of conflict between sensors.
For instance, I read that on one network, there can be only one gateway. However, I also read that if you use NRF24 sensors, you can use different radio channels.
So, how should we manage the various MySensors networks appearing with neighbours ? For instance, during "presentation" phase, the sensor gets a unique nodeID, but is there a risk it asks the gateway from neighbour and get an ID already existing in my own network ?
Later on, how a sensor can send info to a specific gateway ? (here, my guess is that unless we introduce the security options, then all gateways coul read the sensors).
On the opposite, if a sensor is requesting info from controller (requesting time or any other setting), how do we make sure that it asks from correct gateway ? Is it only by setting up different radio channels (and thus ask your neighbour to use a differetnh channel than yours?)

br,
Ricorico94

[gohan]

You have many channels to use so hopefully you will not use the same (change the default one of course) and also you can use encryption just to play safe

[hek]

@ricorico94

Besides channel, you can also change the MY_RF24_BASE_RADIO_ID for nrf24. This will give you the possibility of a huge number of networks on the same frequency if the traffic is low.

https://github.com/mysensors/MySensors/blob/development/MyConfig.h#L418

[LastSamurai]

You can also use the security features of mysensors so that your node doesn't connect to your neighbors gateway even if it uses the same channel. Using a different channel would be easier though i guess.

[ricorico94]

Hi,
Thanks for these hints.
Changing the frequency is probably easy, but does it prevent a new Node to ask for a NodeID from another gateway ?

Regarding the solution with base Node ID, I don't understand how to use that setting. Documentation states :

/**
 * @def MY_RF24_BASE_RADIO_ID
 * @brief RF24 radio network identifier.
 *
 * This acts as base value for sensor nodeId addresses. Change this (or channel) if you have more
 * than one sensor network.
 */
#ifndef MY_RF24_BASE_RADIO_ID
#define MY_RF24_BASE_RADIO_ID 0x00,0xFC,0xE1,0xA8,0xA8

but I don't understand how to use that.. I searched the forum and the internet, but I could not find examples. What mean "0x00,0xFC,0xE1,0xA8,0xA8" ? Are they random values I can decide by myself (and then use the same for each of my sensors) ? Like I could state:
#define MY_RF24_BASE_RADIO_ID 0x01,0x02,0x03,0x04,0xFF
??

Is there a downside of using that setting compared to changing radio frequency ? (it still looks much more simple than using the security.. I couldn't find a tutorial that I can understand.. but I admit I didn't spend hours on investigating security yet. That's on my mid-term to-do-list)

br,
Ricorico94

[gohan]

I'd go with another channel to avoid interference and use cryptography to add some security to your network

[ricorico94]

I understand everyone prefers using different radio channels, but no one knows how to use the MY_RF24_BASE_RADIO_ID setting and what are the pros/cons ?

[hek]

@ricorico94

From the NRF24 datasheet:

https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf

So, you should probably choose address a bit careful.

To change base address just add a define in your sketch like this (before including MySensors.h):

#define MY_RF24_BASE_RADIO_ID 0x00,0xFC,0xE1,0xA8,0xA8