Re: [PATCH wpan-next 1/6] net: ieee802154: Drop coordinator interface type

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Alexander Aring <aahringo@redhat.com>
Cc: Alexander Aring <alex.aring@gmail.com>,
	Stefan Schmidt <stefan@datenfreihafen.org>,
	linux-wpan - ML <linux-wpan@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Network Development <netdev@vger.kernel.org>,
	David Girault <david.girault@qorvo.com>,
	Romuald Despres <romuald.despres@qorvo.com>,
	Frederic Blain <frederic.blain@qorvo.com>,
	Nicolas Schodet <nico@ni.fr.eu.org>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH wpan-next 1/6] net: ieee802154: Drop coordinator interface type
Date: Thu, 9 Jun 2022 17:43:53 +0200	[thread overview]
Message-ID: <20220609174353.177daddb@xps-13> (raw)
In-Reply-To: <CAK-6q+gBCakX8Vm1SHuLfex5jBqLKySUiaZKg3So+zjeJaSehw@mail.gmail.com>

Hi Alex,

> > >
> > >   - How is chosen the beacon order? Should we have a default value?
> > >     Should we default to 15 (not on a beacon enabled PAN)? Should we be
> > >     able to update this value during the lifetime of the PAN?
> > >  
> >
> > Is there no mib default value for this?

I didn't find anything. I suppose we can ask for that parameter at PAN
creation, but otherwise I'll keep a backward compatible value: 15,
which means that the PAN is not beacon enabled (like today, basically).

> >  
> > >   - The spec talks about the cluster topology, where a coordinator that
> > >     just associated to a PAN starts emitting beacons, which may enable
> > >     other devices in its range to ask to join the PAN (increased area
> > >     coverage). But then, there is no information about how the newly
> > >     added device should do to join the PAN coordinator which is anyway
> > >     out of range to require the association, transmit data, etc. Any
> > >     idea how this is supposed to work?
> > >  
> >
> > I think we should maybe add a feature for this later if we don't know
> > how it is supposed to work or there are still open questions and first
> > introduce the manual setup. After that, maybe things will become
> > clearer and we can add support for this part. Is this okay?  
> 
> *I also think that this can be done in user space by a daemon by
> triggering netlink commands for scan/assoc/etc. (manual setup) and
> providing such functionality as mentioned by the spec (auto creation
> of pan, assoc with pan). Things which are unclear here are then moved
> to the user as the operations for scan/assoc/etc. will not be
> different or at least parameterized. The point here is that providing
> the minimum basic functionality should be done at first, then we can
> look at how to realize such handling (either in kernel or user space).

Actually this is none of the 802.15.4 MAC layer business. I believe
this is the upper layer duty to make this interoperability work,
namely, 6lowpan?

Thanks,
Miquèl