NCP vs. RCP / ot-daemon vs wpantund

[P-D-G]

Hello,

I'm currently working with OpenThread, for devices where the OpenThread part will be implemented as either RCP/NCP.

We first planned to use an OpenThread NCP to offload as much as possible to the radio SoC. However, we saw that the wpantund repository was recently archived. I also see some NCP improvements on the same date in commit e06a3ec. So I have a few questions:

1. Is the NCP still supported ? I understand the RCP was recommended over NCP, is this still the case ?
2. Does ot-daemon/ot-ctl support communication with NCP ? If so, is the OT stack processing properly offloaded to the NCP ?
3. Are there some long-term preferences to favor RCP support over NCP (or reverse) ?

Thanks for your work, and thanks in advance for your time :)

[jwhui]

1. Is the NCP still supported ? I understand the RCP was recommended over NCP, is this still the case ?

We are actively working to build out NCP support. We are not planning to use wpantund going forward. Instead, we plan to continue enhancing the existing otbr-agent to support both NCP and RCP modes. You can follow openthread/ot-br-posix#2398 to track the NCP effort.

2. Does ot-daemon/ot-ctl support communication with NCP ? If so, is the OT stack processing properly offloaded to the NCP ?

We are working on adding CLI support for NCP. See openthread/ot-br-posix#2773

3. Are there some long-term preferences to favor RCP support over NCP (or reverse) ?

We plan to support both RCP and NCP. Each model has their own benefit depending on the device requirements.

[P-D-G]

Ack thanks. Just to clarify, we're planning to use a self-contained OpenThread network, without any border router. So we probably won't use ot-br-posix.
Is support for the NCP planned in ot-daemon/ot-ctl for a NCP based nodes ?

[Irving-cl]

Hi @P-D-G,

You can still use ot-br-posix even you don't want border router features. You can disable all the Border Routing features and it will simply be the same as ot-daemon. It can be seen as OT on posix. For example, the Thread stack on AOSP is also built from ot-br-posix but it may not be a border router. (mobile for example) Our general direction is to use ot-br-posix so we don't develop on OT posix anymore.

Regarding ot-ctl (CLI command support in NCP mode), it's under development and will soon be ready. openthread/ot-br-posix#2773