Subject: Re: On Scaling of DNS-SD

From: Stuart Cheshire <[email-masked]>
Date: Tue, 30 Jul 2002 23:16:39 -0700

>I don't know where Apple gets off thinking it can redefine the
>Internet arcihtecture to make DHCP mandatory and to overload
>DNS to change its semantics in a way that breaks applications. 
>frankly, I find it both offensive and technically bankrupt.

Don't be ridiculous Keith.

There's no need to waste the IESG's time with nonsense like this, and
I'm only cc'ing the IESG on this reply to correct this misinformation.

Apple is not making anything mandatory.

I simply stated Apple's position, which is that for problems that are 
solved perfectly well today using DHCPv4 and DNS, we do not support or 
endorse any attempt to define new protocols to duplicate this 
functionality.

We believe that there are cases where no good protocols currently exist, 
and cases where good protocols exist (even though there may not be 
shipping products today that implement those protocols). It is important 
to make a distinction between those two cases. Where the problem is lack 
of a good protocol, designing a good protocol may be warranted. Where we 
believe there is already a perfectly good protocol, but the problem is 
lack of implementations of that protocol, then designing a new protocol 
is not warranted.

We believe that DNS, DNS SEC, DNS UPDATE, etc., are good protocols (or at 
least potentially good protocols). The fact that I know of no consumer 
gateway/firewall/NAT product that currently implements a DNS server with 
DNS UPDATE is not a reason to go and invent new protocols for this 
specific situation. The vendors of these products already have protocols 
available for them to use, should they wish to market a product that 
implements them. If they don't wish to market a product with these 
capabilities, then inventing new protocols is unlikely to change their 
minds on that subject.

Stuart Cheshire <[email-masked]>
 * Wizard Without Portfolio, Apple Computer
 * Chairman, IETF ZEROCONF
 * www.stuartcheshire.org

---

From: Keith Moore <[email-masked]>
Date: Wed, 31 Jul 2002 10:45:35 -0400

>         i used my nodes with mDNS configuration
>         while others are using normal DNS, they interact in some ways
>         (like ftp and/or www).  as i have used older mDNS draft i used
>         "local.arpa" cookie as indication of local names, so my machines
>         can contact both mDNS destinations and normal DNS destinations.
>         it worked without any problem.

yes, it does help if the names are in separate spaces, though if the names
have dots in them it can still confuse applications that expect names
with dots in them to be global.
 
>         btw, define "distributed apps".

I'd define a distributed app as any app which communicates over a network and
has more than two nodes.

Keith

p.s. re: your comment about running code.  running code does help demonstrate
that the spec is implementable, and if there are multiple implementations
of the code that interoperate, it helps demonstrate that the spec is clearly 
written.  it usually doesn't help demonstrate that the protocol scales - 
and the sort of problem I'm concerned about can be viewed as a scaling problem.
i.e. what works well in limited trials does not necessarily work well in
large-scale deployment.  so even if we have running code we still cannot abandon
analysis as a predictor of potential failure.