Dirigera OTBR does not update Thread Network Data after DHCPv6-PD prefix change

Configuration Matter/Thread
1

After a DHCPv6-PD prefix change by the ISP (e.g. triggered by a forced daily reconnection), the Dirigera continues to propagate the outdated (stale) prefix into the Thread Network Data. As a result, Thread clients configure a global IPv6 address via SLAAC using a prefix that is unknown to the home router, causing a complete loss of IPv6 connectivity for all Thread devices.

Is this behavior observed by other OTBR as well?

Steps to Reproduce

  1. Dirigera is operational as an OpenThread Border Router (OTBR)
  2. ISP performs a forced reconnection and delegates a new IPv6 prefix via DHCPv6-PD
  3. The home router receives the new prefix and updates its routing table accordingly
  4. Dirigera does not update the Thread Network Data with the new prefix
  5. Thread clients continue using SLAAC addresses derived from the old, now-invalid prefix
2

BTW I don’t have any experience in this scenario, but just wondering, if you power re-boot the Dirigera does it by chance fix the problem? A re-boot might actually get the Dirigera to send out a Solicit for a PD… and maybe the Thread network would take corrective action if it got one back that was different

3

That is how DHCP works, both in IPv4 and IPv6.
DHCP information have a lease time and you do not just force a new IP range to take effect by changing the router. The information needs to time out on clients.

In IPv4 I could see why a change would be needed, but in IPv6 there should be no reason to force a change. IPv6 have enough addresses that all devices can have one and never need to change it.