Subject: RE: Scalability vs. Periodic Messages (was Re: periodic messages)

From: "Nicolae, Dan" <[email-masked]>
Date: Thu, 10 Aug 2000 09:32:17 -0400

> 
> Dan,
> 
> I believe there was earlier a discussion on the list that 
> zero-conf does
> not necessarily mean small. Therefore, I think scalability is 
> important.
> If the draft does not say this, then I think it should.
> 
> 		jak

Besides the fact that the protocol SHOULD be designed with scalability in
mind, there is also other aspect:

Zeroconf (potentially non scalable) and non-zeroconf (most likely scalable)
protocols MAY coexist. 
That means an non scalable protocol MAY stay enabled even after "the owners
of that network will migrate to using non-zeroconf protocols". So, the
second assumption in section 1.2.4. does not quite stand up. I believe that
the first assumption ("limited size") has already been challenged (no way to
define "small" or "limited"), so ignoring scalability is left with no
excuse.

If it wasn't so far, Scalability IS an issue now. 
Or, a nonscalable zeroconf protocol MUST transition completely to
non-zeroconf when needed (define "needed" now). 
Or, the non-zeroconf protocol the host just transitioned to MUST allow for
disabling/enabling the zeroconf protocol coexistence. With DHCP is easy; a
AutoIP option can kill AutoIP. But how about mDNS or SLP, SSDP etc.? And how
about the zeroconf protocol relying on a DHCP option (non-zeroconf)? This
makes it non-zeroconf.
Or, ...

dan

---

From: Erik Guttman <[email-masked]>
Date: Thu, 10 Aug 2000 15:46:33 +0200 (MET DST)

> about the zeroconf protocol relying on a DHCP option (non-zeroconf)? This

Creating requirements which specify that scalability is important
but not the overriding consideration will help us in the standardization
of protocols that scale better.  It will be an important criteria which
the IESG and WGs can apply when evaluating candidate protocols.

Please note that it is possible to create a scalable zeroconf protocol.
These protocols don't have to be relegated to link-local operation, 
either.

We succeeded in this respect with SLP.  When you turn on stateless 
directory agents, you effectively turn off multicast-based requests.  
This is a fundamental requirement of the SLP, which uses the same 
protocol peer to peer as when a DA is present.  

The same will not be possible for DHCP, as it doesn't make sense to 
do peer to peer DHCP.  But similar things are indeed possible for 
mDNS / DNS and AAP for zeroconf nets / MADCAP.

Erik

---

From: Daniel Senie <[email-masked]>
Date: Thu, 10 Aug 2000 09:58:02 -0400

> the IESG and WGs can apply when evaluating candidate protocols.

Good. I agree we should strive for scalability. I started this thread up
because of a perceived inconsistency in the -04 draft. I wanted to see
what other folks said before I added to the discussion further.

It is indeed important that the scalability (or lack thereof) of
zeroconf not affect other traffic on the wire. As rightly stated, we're
going to have both zeroconf and non-zeroconf coexisting.

Netbios has some attributes of what we're talking about, and in
conjunction with IP autoconfig works fairly well, but is VERY chatty on
the wire. I would like us to keep that example in mind as we move
forward.

-- 
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Daniel Senie                                        [email-masked]
Amaranth Networks Inc.                    http://www.amaranth.com