Re: [DNA-BOF] Using L2 to provide Instantaneous Movement Detection andNeighborhood Discovery

[Pekka Nikander <pekka.nikander@nomadiclab.com>]

Bernard Aboba wrote:
> That said, here are some issues that can arise from this proposal:
> 
> a. It assumes that the AP only offers access to a single network. APs
> (like switches) are capable of supporting VLANs, in which case the AP can
> offer access to multiple networks.  Which prefixes should it advertise in
> this case?  If a network is advertised, can the host hearing the
> advertisement then conclude it will be able to obtain access to that
> network?

That's basically an operational issue.  We can't assume that all APs
will advertise prefixes ever, and therefore the clients must be
prepared to figure out the situation even then.  Some operational
guidance is needed, but IMHO nothing more.

Hence, I don't see that as a road block.  Personally, I think that
the *ability* for an AP to broadcast internetworking layer
configuration information would be great.

> b. ...  This implies that advertisement in the Beacon and Probe
> Response could be misleading.

Yes, this must be documented and the hosts must be prepared
for it.  If opti-DAD gets used, I don't see that as a problem,
though.  Some careful thinking is certainly needed.

> For all these reasons, if prefix(es) are present in the Beacon and Probe
> Response they need to be treated as *potential* networks to which the host
> *might* be connected. This means that this particular advertisement would
> act as a *weak* hint.

Agreed.  OTOH, maybe the advertisement itself could have a flag
that says
   - this AP does not provide any other upper layer configurations, or
   - this AP may provide also other upper layer configurations

That would allow the advertisements to act both as weak or strong hints.

--Pekka Nikander