Re: [homenet] Understanding DNS-SD hybrid proxying [was: Firewall hole punching]

[Markus Stenberg <[e-mail]>]

> On 24 Nov 2016, at 11.28, Tim Chown <[e-mail]> wrote:
> In dnssd we have the “stitching” topic on our plate, around operation of dns-sd in unmanaged multi-link networks.  So this is timely discussion.
> 
> We’re beginning work on a BCP for the use of the discovery/advertising proxy in enterprise/campus networks, where there is administrative configuration, and scalability is a concern. The stitching topic would likely form part of a corresponding BCP for unmanaged operation, as per a multi-link homenet.

For the record, 'stitching' combined with mdns is really hard. One of the reasons I gave up on my original mdns proxy designs, which incorporated stitching. 

As long as there is no conflict, it is trivial, but dealing with conflict in user-friendly manner is essentially impossible in presence of any resource name rewriting (and that inevitably happens when hybrid proxy is involved).

mdns conflict precedence may change as result of rewrites -> have to do really ugly things to force one party to rename, if you want the ground truth to match what is presented in the stitched zone. If you do not want that, then the problem becomes just matter of providing long-lived name rewrites if and only if conflicts are detected, and it is not much more fun either.

Cheers,

-Markus