More details on DHCPv6-PD prefix renew/rebind conditions + AIL change situations

[EskoDijk]

Section 5.2.3 defines the mandatory DHCPv6-PD client role for the stub router. However, there are no details here what should trigger the stub router to renew/rebind the prefix lease.

• A reference to RFC 8415 should be added (as it contains some requirements on this topic).
• See section 18.2.12. Refreshing Configuration Information of RFC 8415.
• Do we define the SHOULD requirements of 18.2.12 about detecting a new network (new AIL) as mandatory for the stub router, or not? (If not: has consequences for wider IPv6 connectivity in such new-AIL cases)
• And what about the SHOULD requirement that involves "if the client detects a significant change regarding the prefixes available on the link (when new prefixes are added or existing prefixes are deprecated), as this may indicate a configuration change. " -> can we specify this better? What are the significant changes in our case? And how to do this detection? (e.g. monitor RAs?)

[EskoDijk]

For this issue, we could reference the improved text in https://datatracker.ietf.org/doc/html/draft-ietf-dhc-rfc8415bis-04#name-refreshing-configuration-in instead of RFC 8415.

This text should be sufficient detail that stub router implementers know what to do. (Or at least, the DHC WG thinks it is enough for DHCPv6 client implementers to know what to do :-) )

PR with this pointer text is still needed.