(Open)Thread and NetworkManager/IPv6 Neighbor Discovery Protocol

[agners]

We are using NetworkManager on a device communicating with Thread devices through Thread border routers. We've noticed some issues around IPv6 Neighbor Discovery Protocol (NDP).

In NetworkManager 1.34 had issues removing outdated/removed IPv6 Router Information Options announcements (RIOs). It seems that this is fixed with 1.40.10 and newer versions at least.

Secondly, NetworkManager currently only supports a single route learned via RIO. This is problematic when multiple BRs announce the same network: Whenever another router announces a RIO, the old one is removed. Thus, the path taken switches back and forth. This might already be problematic, not sure. Only having a single route certainly not ideal when the last learned RIO goes offline: The other routes of other BRs won't be in the routing table, hence the user will experience connectivity issues.

Both issues have been discussed with NetworkManager developers here. Currently it seems there are no plans to address the later.

Are there other known issues with NetworkManager? What features/options of IPv6 NDP are typically required for a device trying to talk to Thread devices behind BRs?