Matter Binding after disconnecting OTBR

[jayveer]

I am working on Matter binding between two matter enabled thread devices where i have flashed the light bulb code in EVBT840 and light switch in nrf52840 kit

I am using Raspberry pi 4B as OTBR and commissioning is done using chip tool in linux pc. After commissioning both the devices in thread network and matter binding is done between both the device is done where when i press the switch in matter switch the matter bulb glows. So after the matter binding between both the matter devices when i disconnect the OTBR the communication between them till remain for around 2 mins where without OTBR i can control bulb with switch but after that the connection breaks.

So once commissioned and matter binded ,then removing the OTBR should the connection between them still remain or there is issue with my ecosystem ?

[jayveer]

Is there any update ?

[Charlie]

Hi Jayveer,

Sorry for the late reply. We are short on staff due to summer vacation.

Currently, it is not possible to control Thread devices over Matter devices without Border Router. The Border Router is an SRP server which is needed for devices to be able to resolve other devices over matter.
Additionally, while the border router is removed the Thread devices remove external IP address which is in use during Matter communication. The Thread topology is recreated and if the light bulb is Thread FTD device then it start to be a leader in Thread topology.

In your case, I have no control over what firmware the EVBT840 is running, however, if the device (as light bulb) is not an FTD Thread device then without Border Router the devices cannot re-create Thread network due to lack of leader capable device. The Nordic Sample of Light Switch is MTD Thread device. There must be an SRP server in the Thread network to let Matter devices discover each other's IP addresses. This doesn't have to be a border router, it can be any Thread router that enables the SRP server functionality though.

Best regards,

Charlie

[jayveer]

Thank you so much Charlie ,

Your answer would really be helpful for us.

We are flashing the Nordic sample of Light bulb in EVBT840.So will it be FTD thread device ?

[Charlie]

Yes, the Light bulb runs as an FTD router.

[jayveer]

ok so we are flashing the Nordic sample Light bulb in nrf52840 and Light switch in EVBT840 . So as the Light bulb is FTD , after removing the OTBR it has to became the leader and recreate the thread topology but it is not happening. The light bulb is not able to became the leader and the connection between the switch and bulb breaks after 2 mins of removing the OTBR , so according to you what could be issue, could it be of build configuration one ?

Best Regards,

Jayveer