Subject: RE: Single vs many solution(s)

From: "Vasile Radoaca" <[email-masked]>
Date: Mon, 5 May 2003 23:21:19 -0400

Alex,

  I think the ideal goal is to have only one solution, but such ideal usual
can be achieved if we are working in a pure theoretical environment, without
market considerations. In reality the market is driving in most of the
cases, and some assumptions made two years ago are not any more valid -
there are categories of SPs that pretty much have disappeared from the map.

  You stated very clear that a problem space needs to have a single
solution. I fully agree with you as a goal, but ut the issue that we face
right now is that the problem space is not well concluded and well
understood just purely from technical considerations. 

 The L2 VPLS is a complex space with multiple dimensions, and the vendors -
in the last two years -  have worked from different angles, optimizing one
or more dimension(s) of the problem space (probable the downturn in the
market it self, was part of the problem). Without to contradict each other,
most of the solutions are closed in a specific dimension, based on some
objective/subjective parameters or experience and some criteria of
optimization. Moving in only one dimension doesn't scale it self.
 
 The fact we do have more than one solution, I think is a good thing, and
doesn't contradict that we can't move toward one solution, if we are driving
diligently, and willing to make compromises. Taken such research value in
consideration, would be a positive sign that IETF is looking to create a
solution that would be valid for a while. Reading the mailing list, I
observed the same wise advise from most of the SPs, and this reflect not a
"problem" but a reality.

Cheers
   Vasile
  
-----Original Message-----
From: Alex Zinin [mailto:[email-masked]] 
Sent: Monday, May 05, 2003 5:27 PM
To: [email-masked]
Cc: Yakov Rekhter
Subject: Single vs many solution(s)

Yakov,

[I took the liberty to change the subject line]

>> I believe the goal for the WG should be to work out
>> a single solution.

> That is certainly not in the charter. In fact the goal
> you stated above directly contradicts what is in the charter:

>    Multiple approaches are being developed as each approach 
>    has particular characteristics and differing scope of 
> applicability.

Thanks for pointing out a possible contradiction. I don't think it exists.

My opinion (and I think it would be safe for me to say it is consistent with
that of the IESG) is that as long as different solutions are solving
different problems (or, as the text of the charter says, have different
scopes of applicability), it is fine to have more than one solution.
However, for a single problem, we only need a single STD'ized solution.

> And if you believe that for VPLS the goal should be a single solution, 
> then why wouldn't you insist to have the same goal for L3 VPNs ?

you forgot to add "and if you wouldn't insist on a single solution for L3
VPNs, then why do you insist on this for L2 VPNs" ;-)

The reason is I don't want to restart the L3 VPN work in the IETF and/or
revisit the decisions that have been made in the past, while I still see a
reasonable opportunity to steer the L2 VPN work.

> Also, if you insist on a single solution, wouldn't that
> imply a single auto-discovery mechanism for VPLS ?

This would definitely be my preference.

Alex

---

From: Alex Zinin <[email-masked]>
Date: Tue, 6 May 2003 11:44:18 -0700

Vasile,

 Hopefully my reply to Richard last night helped clarify some points.

 Regarding the complexity of the L2 VPLS space and hence the difficulty
 of agreeing on a single solution--can I ask you to clearly formalize
 a few problem scopes where you believe different solutions are needed
 and explain why? I would expect that each scope would have a distinct
 set of characteristics.

Alex