Subject: RE: PAA Discovery

From: George Tsirtsis <[email-masked]>
Date: Fri, 1 Feb 2002 17:53:24 -0500

James,

Did you look at Paal's draft at all? He is actually discussing a couple of
ways including one based on DHCP....but as he says he is missing SLP which
may also be considered.

I think you are correct about the fact that there is no need for yet another
protocol ...an extension of something that already exists should do the
trick, I also think Paal will agree with this statement since his draft does
not discuss any "new" approaches...just extensions.

George
-----Original Message-----
From: James Kempf [mailto:[email-masked]]
Sent: Friday, February 01, 2002 10:12 PM
To: Paal Engelstad; [email-masked]
Subject: Re: PAA Discovery

> I recently submitted a draft proposing a mechanism for discovering
IP-addresses of PAAs. It is a lightweight and straightforeward solution
based on extensions to RAs and/or to DHCP messages.
>
> There are naturally other alternatives:
> More heavyweight discovery: SLP

I'll dispute this assertion. The SLP implementers group is currently
working to take SLP to draft standard and has eliminated a number of
mechanisms that were either not implemented or were deemed to be too
heavyweight.
Check draft-guttman-rfc2608bis-01.txt.

Furthermore, I would like to argue strongly against a "roll your own"
discovery technique approach. If you
don't like SLP try:

1) DHCP

2) DNS/mDNS

3) LDAP

Unless you are talking about something like routing, there is absolutely
no reason to come up with
a new discovery technique. I've spent the last two years going around to
working groups who
argue that their protocol is so "different" and "unique" that they must
invent a new discovery protocol.
The problem with this is that it is another special, one off discovery
protocol that must be administered
Not only that, but somebody has to implement the tools to administer the
discovery protocol. Imagine what it would be like if every WG decided
they wanted to implement their own transport protocol, or name service
protocol, or <pick a currently used protocol for a standard architecural
element>. Unfortunately, the IAB/IESG hasn't yet seen
fit to try to enforce architectural consistency on service discovery,
since it is in some sense, not
perceived as a serious enough problem. But for the people who have to
implement the tools and
administer it, it sure enough is.

We don't need a special purpose discovery protocol for PANA, let's just
figure out what the right existing protocol is and how to use that.

                jak

---

From: "James Kempf" <[email-masked]>
Date: Fri, 1 Feb 2002 15:29:55 -0800

George,

There are 4 suggested mechanisms, two use DHCP, two use router
advertisements. It's the latter two
I am complaining about. Router advertisements are not the place to put
service discovery information.

            jak

----- Original Message -----
From: "George Tsirtsis" <[email-masked]>
To: "'James Kempf'" <[email-masked]>;
<[email-masked]>
Sent: Friday, February 01, 2002 2:53 PM
Subject: RE: PAA Discovery