Hi Martin,

Thanks for the feedback. I've included your questions below.

> LPD-4: The IPv6 CE Router MUST give out a IA_PD of the remaining prefixes with a IA_PD size of 64.

Why not honor the IA_PD size requested by the requesting router? Do you expect that possible another cascade router would be switched to DHCPv6 relay mode?

[TW] - Yes. We expect Routers getting a bigger then /64 to be DHCPv6 Server, typically at the edge to ISP. We are suggesting other routers getting IA_PDs of size 64 on the WAN interface to act as relays on the LAN interface.

> LPD-6: If a IPv6 CE Router recieves IPv6 prefixes of size 64 it MUST enable delegating relay according to [RFC8987]. The MUST forward all the DHCPv6 Relay messages to the All_DHCP_Relay_Agents_and_Servers multicast address.

Manually configured unicast address of upstream DHCPv6 server would not also be acceptable?

[TW] - RFC 7084 had the goal of zero configuration requirements for CE Router. I was trying to keep to that by suggesting using the multicast address as the requirement. We could make it SHOULD if we feel that's more appropriate.

I'll look into what requirements from the DHCP Relay draft we should call out.

~Tim

On Tue, Jan 17, 2023 at 2:48 PM Michael Richardson <mcr+ietf@sandelman.ca> wrote:

(Hi Martin, I'm just the messenger, your questions are all pretty good. For
others, I think it was not obvious that they are about draft-winters-v6ops-cpe-lan-pd-00.
But, more than my brain can handle right now)

Ted Lemon <mellon@fugue.com> wrote:
>> Why not honor the IA_PD size requested by the requesting router? Do you
>> expect that possible another cascade router would be switched to DHCPv6
>> relay mode?

> What’s the use case for this behavior? And yes, we expect routers to act as
> DHCPv6 relays.

I think that actually we've created an ambiguity about whether they are
DHCPv6 relays or if they are full DHCPv6 servers.
There are arguments both ways, and in some cases the choice is transparent to
the end system, but in other ways it is not.

The lack of a standardized way to communicate DHCPv6-server PD to
DHCPv6-relay, and the expectation that the relay would just *snoop* on the
DHCPv6-PD contents has bugged me for a long time. If we are going to
recommend that they act as relays, then I'd like to fix that.

Either way, Tim's v6ops draft-winters-v6ops-cpe-lan-pd-00 should clarify.
LPD-1 suggests the IPv6 CE Router is a server, not a relay.

--
Michael Richardson <mcr+IETF@sandelman.ca> . o O ( IPv6 IøT consulting )
Sandelman Software Works Inc, Ottawa and Worldwide
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