Re: [babel] BABEL / MANET / ROLL and multicast

[David Schinazi <[e-mail]>]

On Tue, May 3, 2022 at 12:03 PM Juliusz Chroboczek <[e-mail]> wrote:

> > Out of curiosity, what's the use-case for using multicast over a mesh
> network?
>
> In public meshes, essentially mDNS.  People want to be able to find their
> printer even if they're using a mesh network to cover their huge American
> home.
>
> I'm not sure if the military have other needs, if so, they're not telling
> (at least not to me).
>
> > When it comes to device/service discovery, we've found that a
> unicast-based
> > register/query model is much more reliable and wire-efficient.
>
> I agree that it would be more efficient for the printers to register with
> the local DNS proxy when they acquire or renew a DNS lease, but that's not
> what the market has chosen.  (Some people at Apple may or may not know more
> on the subject, and they may or may not be called Stuart.)


That's not what the market has chosen over Ethernet, but it is what the
market is
apparently going to choose for mesh home networks. Leading companies in the
smartphone and home automation spaces have joined together to create Matter
<https://en.wikipedia.org/wiki/Matter_(standard)>, a new home automation
standard based on IP and IEEE 802.15.4. Their plan for service discovery is
to
use DNSSD (RFC 6763) but not mDNS (RFC 6762). mDNS is one way to
perform DNSSD using multicast, but you can also perform DNSSD using
unicast, and that's what we're building over in the DNSSD working group:
https://datatracker.ietf.org/doc/rfc8766/
https://datatracker.ietf.org/doc/html/draft-ietf-dnssd-srp
https://datatracker.ietf.org/doc/html/draft-ietf-dnssd-advertising-proxy
(Someone named Stuart might be involved with these documents, and
someone named David might be chairing a relevant working group)

David