Subject: Re: FYI: New ID submission- GRP

From: [email-masked]
Date: Tue, 6 Mar 2001 13:59:13 -0500

Why do you want to reinvent this mechanism? 

GRP is more simple and automatic than ICMP Router Discovery. It is not 
tied to any other protocol (other than ARP), does not rely on multicast, 
does not assume support for outside "black hole" detection, does not 
require configuration of a host based router query address, does not 
define new packet types, does not include complex preference schemes 
(which one can argue won't be needed in Zero Conf nets), provides 
incorporated "black hole detection" and permits configuration-less dead 
interval detection on hosts. For these reasons (simplicity and 
automation), we feel that GRP is more closely aligned with the goals and 
spirit of Zero Conf. It is not our goal to argue the religious aspects of 
GRP, ICMP-RD or any other gateway discovery protocol. 

Your suggested
approach is completely tied to the 169.254/16 address block, 

We are not tied to any address or block. The suggested use of a single, 
well known GRP address permits configuration-less gateway router discovery 
by hosts. The address could be changed if that was needed. Furthermore, 
since we can assume what the subnet and prefix will be, GRP should not 
have to wait for the host's interface address to be determined before 
processing "protocol" packets. Note that we also assume that the only time 
the GRP router address is directly used (not reading ARPs)is during 
host-gateway query. 

and doesn't
provide any advantage over a protocol already understood by hosts and
routers.
 
GRP does not loose functionality to ICMP-RD, but has advantages, see above

Spence

Spencer Giacalone, Predictive Systems
---------------------------------------------------------------
"Nothing so much prevents our being natural 
as the desire to seem so" -Francois, Duc de 
La Rochefoucauld

Daniel Senie <[email-masked]>
Sent by: [email-masked]
03/05/01 09:18 PM

        To:     [email-masked]
        cc:     [email-masked]
        Subject:        Re: FYI: New ID submission- GRP

It appears to me you've reinvented router discovery protocol. See RFC
1256. Router discovery has been around for quite some time, and works
fine. Why do you want to reinvent this mechanism? Your suggested
approach is completely tied to the 169.254/16 address block, and doesn't
provide any advantage over a protocol already understood by hosts and
routers.

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

---

From: Daniel Senie <[email-masked]>
Date: Tue, 06 Mar 2001 17:20:39 -0500

> GRP, ICMP-RD or any other gateway discovery protocol.

Your I-D submission made no mention of ICMP Router Discovery. Further,
it had only ONE citation of any sort. You might want to rewrite your
draft to include your reasoning for inventing a new mechanism, and why
you believe it is necessary in the face of similar technology which is
(and I think you missed this in my comments) already implemented in
hosts and routers today. In reading your draft, I came away with the
impression you (where'd this "we" come from, with one author?) were
unaware of ICMP Router Discovery.

I will likely still disagree with you, but urge you to at least make the
comparative arguments in your document and defend your reasons for
implementing something new.

> the GRP router address is directly used (not reading ARPs)is during

That single address could just as easily have been a poke at any
address, including a multicast address, a martian address (0.0.0.0) or
most any other odd case. Your document specifically said you wanted to
use 169.254.0.1 because it's presently listed as reserved. That appeared
to be a tie to a specific block.

Again, add these arguments to your I-D.

> GRP does not loose functionality to ICMP-RD, but has advantages, see above

"loose" or "lose" Not sure what you're arguing here. In reading your
arguments above, I'm not convinced there are compelling reasons to
implement GRP, rather than using the existing, deployed protocol.

Overall, you've proposed we use NAT, which has been widely implemented
in routers, but do so without DHCP, which also is present in nearly
every NAT device on the market, and create a new router discovery
protocol which requires every client system and stack to be altered. I
wonder why implementers would like this approach over using an existing,
off-the-shelf $120 NAT/DHCP box, and having existing machines just
function? What's gained by all this extra work? You don't give enough
arguments in your I-D to understand why your approach is compelling.
This is just my opinion, of course. Other WG members may see it
completely differently.