Re: [v6ops] Updating RFC 7084 - alternate logic

[Alexandre Petrescu <[e-mail]>]

Le 05/12/2022 à 15:39, Alexandre Petrescu a écrit :
> 
> 
> Le 05/12/2022 à 15:15, Gert Doering a écrit :
>> Hi,
>>
>> On Mon, Dec 05, 2022 at 02:57:28PM +0100, Alexandre Petrescu wrote:
>>> But it is not that straightforward.
>>
>> It is :-)
>>
>>> For that to work, one possibility would be a for the AP in router mode
>>> to run a DHCPv6 Relay.  But as far as I know there are no WiFi access
>>> points that run DHCPv6 Relay software.
>>
>> If the "AP in router mode" wants to do routing, and IPv6, it needs
>> to understand prefixes left *and right*.  So for the "right side prefix",
>> it needs to speak DHCPv6-PD anyway, to get a prefix assigned from the
>> ISP router.
>>
>> In IPv4 land, all these "things in router mode" will just do hierarchical
>> NAT44, but that's not how you do IPv6.
> 
> I agree.
> 
>>
>>> Another possibility would be that the snac router is precofigured with
>>> the address of the DHCPv6 server (ISP's inhome router), so it does not
>>> need to discover it across IP hops, because multicast discovery across
>>> IP hops does not work.
>>
>> You cannot do DHCPv6-PD across a non-participating intermediate router,
>> because that router needs to add forwarding entries. 
> 
> Fair enough.

I correct myself: it _is_ possible to run DHCPv6-PD (and
DHCPv6-Addresses) across a non-DHCPv6 set of intermediary routers,
without a need to update the routing table entries of these intermediary
routers upon prefix allocation.   The secret lies in pre-configuring the
routing properlY.

Alex

> 
> Still, the configuration I described is common in many places: WiFi APs 
> in router mode (as opposed to bridge mode) are used extensively in home 
> settings.
> 
> So I am not sure how good is it to assume that they dont exist.
> 
>> And no, "having
>> a routing protocol on the right side" is not *less* complicated than
>> just having DHCPv6-PD support.
> 
> Fair enough.
> 
> But there is already a hard time in finding DHCPv6 Clients and Servers 
> in these home devices (APs) that looking for a routing protocol presence 
> in APs will only further daunt the task.  HNCP was designed for that but 
> I dont see it.
> 
> Alex
> 
>>
>> Gert Doering
>>          -- NetMaster
> 
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