Subject: Re: [v6ops] ND cache entries creation on first-hop routers
From: Alexandre Petrescu <[email-masked]>
To: Jen Linkova <[email-masked]>
Cc: V6 Ops List <[email-masked]>
Date: Fri, 5 Jul 2019 11:34:19 +0200
List-Id: v6ops discussion list <v6ops.ietf.org>

Hi Jen,

Le 05/07/2019 à 05:50, Jen Linkova a écrit :
> Hi Alexandre,
> 
> On Wed, Jul 3, 2019 at 10:49 PM Alexandre Petrescu 
> <[email-masked]> wrote:
>> I am reading through this draft trying to identify whether the
>> indicated ND problem (router lacking ND entry for host's GUA makes
>> drop first incoming packet to GUA) happens on a ptp link like 4G,
>> or on a shared link like WiFi.
>> 
>> On what was it tried?
> 
> Well, I observed it on WiFi (I guess you should be able to see the 
> issue in Montreal).

It is good to know for WiFI.  Let me try on Ethernet.

>>> The router ND cache, however, might contain an entry for the
>>> device link-local address (if the device has been performing the
>>> ND process for the roiter LLA) but there are no entries for the
>>> device GUA.
>> 
>> But has the host DADed (sent NAs) when it formed its GUA?  I guess
>> that would be heard by router, to create that ND cache entry.
> 
> 1) Those NSes are sent from unspecified address 2) they are sent to
> the solicited node mcast address so routers might not even receive
> them.

Ah I see.  It's not NSs that are necessary, and worse, the routers that 
dont implement link scoped multicast on WiFi would not see them either.

But how about NA?

An NA was issued by my Ethernet adapter of my Windows 10 after I 
manually assigned fd00::1/65 on it; it was issued to a multicast 
address, informing all-nodes that it has that MAC address.  The Router 
receiving it would presumably associate that link-layer address to 
fd00::1/65.

I think that's how the GUA of Host is supposed to get its way in the NC 
of Router, probably.

Alex

>