Alternatives to the flag (Was:Confirmation to advance: draft-ietf-6man-ipv6only-flag-05)

[David Farmer <[e-mail]>]

On Tue, May 14, 2019 at 5:00 PM Philip Homburg <
[e-mail]> wrote:

>
> I'm saying that in the context of IPv6 connectivity, RFC 3927 is not needed
> unless explicitly enabled by the user.
>
> So the only change is that in the context of IPv6 it would be off by
> default.
>

Ok, I could live with that. But, when I've heard this kind of thing
discussed before there were serious objections to it. The objections I
remenber heraing were the change you propose effectivly breaks local
printing from a dual-stack host to an IPv4-Only printer if there are any
problems with the local DHCP server.

So, I'm not willing to drop what I think is a viable solution to the
problem unless other stakeholders are willing to buy into this kind of
change. In particular, I'm thinking the people maintaining mDNS in dnssd
wg. I can't see making the change proposed above without their buy-in.

In theory, an IPv4 stack could passively detect the filtering of Ethertype
0x0800 and 0x0806 by passively looking for other ARPs and/or IPv4 service
discovery traffic. However, both of these types of MAC layer broadcast
traffic are typically suppressed on most WiFi networks by the use of proxy
ARP and service discovery proxying or other forms of control or filtering
to limit MAC layer broadcast which is very inefficient on WiFi.  And,
battery-powered WiFi devices is where suppressing the futile IPv4 traffic
is most useful in this whole discussion.

So I think we either need the flag or disable RFC 3927 by default on
dual-stack hosts.

So my question to the WG chair and AD is how do we get input from other
stakeholders on the viability of alternatives to an IPv6-Only flag.

Thanks
-- 
===============================================
David Farmer               Email:[e-mail]
Networking & Telecommunication Services
Office of Information Technology
University of Minnesota
2218 University Ave SE        Phone: [phone]
Minneapolis, MN 55414-3029   Cell: 612-812-9952
===============================================