Re: [v6ops] RFC7084 - absence of req of prefix presence in PIO on LAN?

[Alexandre Petrescu <[e-mail]>]

Le 14/11/2019 à 19:16, Brian E Carpenter a écrit :
> On 15-Nov-19 01:49, Alexandre Petrescu wrote:
> ...
>> I think RFC8028 sounds in context: "First-Hop Router Selection in a
>> Multi-Prefix Network".
>>
>> However, I am not sure where RFC8028 would apply: is it between the CE
>> Router and the two ISPs?  Or is it between in-house Host and the single
>> CE Router?
> 
> It is only useful in the case of *more than one* CE Router. As far as
> I know, that is not illegal.

I think too that a design of the home network should allow for more than 
one CE Router.  Some home networks do that.  For that it makes sense to 
require the use of RFC8028.

However, I am not sure how to express the need of RIO.

There might be no need of the use of RIO if there is only one CE Router, 
because that is the default router for Hosts in home.  As such, it is 
strange that RFC7084 requires RIO without telling why.

If there are two CE Routers, I am not sure how to fit the use of RIO.

If RIO _is_ used in the context of two CE Routers, then there are 
certainly some requirements on how to use them, in combination with the 
default router capability, and with a requirement to avoid large loops 
cross-ISPs.

There might be a case where only one of the CE Router is the default 
router for Hosts at home, and thus it must not use RIO.  The other CE 
Router must use RIO but must not advertise itself as a default router.

There might be a case where both CE Routers are default routers for 
Hosts at home, but each advertises in PIO a distinct prefix.  In that 
case, there is no need of RIO at all.

Then, there might be cases where there are 3 CE Routers, or more.  That 
would need to be described as well.

Alex