This advice does not look correct to me because:
- One /64 prefix cannot be split into two /63; actually /64 should not be split further.
- For the choice of suitable ip6assign values, the prefix size received from upstream should be considered, rather than the previous ip6assign value of the lan interface.
Am I misunderstanding something?
I agreee it is important to check the values of ip6assign, even more so if routers are cascaded (which was not discussed there).