Subject: re-chartering L2TP

From: Vernon Schryver <[email-masked]>
Date: Tue, 16 Jan 2001 10:52:43 -0700 (MST)

> From: "W. Mark Townsley" <[email-masked]>

> ...
> > > Are you any more clued into the "committee minutia" and such at present?
> > > Are you any less surprised to hear yourself commenting on it now?
> > 
> > That sounds like a misleading statement in the sense that it implies
> > that I did express an opinion on the charter last summer.  I really
> > don't think I did.
>
> This was not a statement, it was a question. Regardless of what you did
> last summer (this sounds like a bad movie already) you were shocked that
> you would have made comment on charter minutia at that time based on
> your admitted lurking position in this group. I am curious as to why now
> is any different than then. You either don't know yourself any better
> now than you did then, or you are paying attention to this group's
> actions more. 

That is an intentionally misleading statement.  I did not express shock
at having previously commented on the charter, but instead politely pointed
out that I had not made such comments.  Moreover, as we all know, "lurking"
does not mean "ignoring," but instead denotes "quietly listening."

If modifications to the charter of the L2TP working group were minor
or required only to complete its work, they would be reasonable and
in my personal view not worth arguing or even talking about.  However,
making the working group a permanent fixture, or more accurately, a
permanently available rubber stamp for proprietary technically bad
ideas are something else.

As far as I can tell, Mr. Townsley has tried to substantially modify the
charter of this working group without obtaining the consensus of mailing
list.  Contrary to his recent statement in another message, a passing
reference to mention of a change in charter in IETF meeting minutes does
not constitute a call for comments on such a change.  I don't think he
meant to do anything bad with the charter and I think he really believes
that the group should last forever to handle tunneling anything over
anything.  I think that would conflict with the charters of other groups,
but even if I'm wrong, it is a substantial enough change to require
consideration by the rest of the IETF.

Where are the words of the new charter, since it is now only proposed
and no longer a fait accompli?

> > > "L2" originally came from L2F, which (From RFC2341) referred to L2 as,
> > > "link layer (i.e., HDLC,
> > > async HDLC, or SLIP frames)."
> > 
> > That is a misleading statement of the history of the working group as I
> > recall it.  The "L2" in the group's name came from the Cisco protocol,
> > not from the reason Cisco named the protocol.  The group was not created
> > to deal with arbitrary L2 packets or protocols, but instead was created
> > to deal with the multi-chassis problem.
>
> The group was created to merge PPTP and L2F. The multi-chassis problem
> was *one* of the motivations for L2F at cisco. The multichassis problem
> certainly was not the widest use of PPTP at the time. 

That is a red herring.  PPTP is still not widely used to handle the 
multichassis problem.

Contrary to Mr. Townsley's implication and to what I recall of his
expressed preferneces over the years, the L2TP group was not chartered to
be a general purpose tunnelling group, handling not only the tunneling of
arbitrary layer 2 packets over IP as in the current issue, but arbitrary
packets over other arbitrary layers.

> > >                       if we have created something that can be built
> > > upon, I see no good reason to start from scratch elsewhere.
> > 
> > Protocols such as the lastest bad idea that has nothing to do with
> > PPP are not building on L2TP.
>
> I think an open mind is a better route to take. That said, I see very
> well crafted arguments in favor of using existing protocols (BCP and PPP
> with L2TP) for the Ethernet over L2TP case. I prefer this type of
> discussion in the group vs. a closed, "we only do PPP, go away if you
> don't like it" approach.

Such "we only do PPP" arguments are appropriate.  IETF working
groups are not supposed to become permanent fiefdoms nor universal
solvents.  They are supposed to do their chartered jobs and finish.

The many years this working group required to approach its chartered
goal and the continuing technically bad ideas such as the current
one are good reasons to disband the working group sooner than later.

Vernon Schryver    [email-masked]

---

From: "W. Mark Townsley" <[email-masked]>
Date: Tue, 16 Jan 2001 14:11:21 -0500

> does not mean "ignoring," but instead denotes "quietly listening."

You're words:

"I'm surprised to hear that I expressed an opinion about it."

> ideas are something else.

Rechartering to include a standard manner for extension of L2TP for
other transport types very well may extend its life, but does not
necessarily make it a permanent fixture. There will be no rubber stamps
in this group. Quite the contrary, accepting the items within the group
allows for common mechanisms to be created (the Service Type draft is
one such example), appropriate review of such items within the group
(the current PPP/BCP debate is one such example), etc. If you want to
talk rubber stamps, let's compare this to an individual submission that
gets an Informational RFC number with substantially less chance for
review.

My goal is to provide a forum for open discussion and technical review
for items relevant to L2TP. The original and current charter includes:
"Define and review the definition of any additional IETF AVPs which are
of interest to the group." So far, the drafts for other L2 types that
have been accepted into the group have added nothing more than
additional AVPs to the protocol. No new messages, no change to the state
machine, no change to the L2TP header, etc. In fact, at the Pittsburgh
meeting I was adamant about keeping the scope of the work to within this
range of extension. I believe the meeting synopsis reflects this.

If such activity means we ultimately extend the charter a bit to take in
more work where appropriate, I think we have done the community a favor
by reacting in a agile manner. Different WGs have to operate in
different manners depending on what they are trying to accomplish and
how successful (in terms of deployment and interoperabilty) the WG has
been. When code is being written faster than the standards documents,
you may have to grease the standards process in order to allow it to
catch up with the code. When the reverse is true, WGs ask for more
sample code to be included in documents, public domain source to be
released, etc. in hopes that the standard would be deployed and accepted
faster. There is a certain amount of balance here, and we are far from
the latter. This WG is fairly powerless in slowing the writing of code
and deployment of solutions in this space right now. To think otherwise
is naive. My belief here is that being open to extension is the better
approach in hopes that the solutions are well documented, understood,
and reviewed rather than put together in a relative haphazard manner
with less chance for interoperability and code reuse.

That is how I choose to run this group right now. If you don't like it,
feel free to discuss it with the Area Directors.

> consideration by the rest of the IETF.

That is why the IESG must approve the charter change. It is also why I
have already discussed this at length with one of our AD. I do not think
that the IESG will approve anything that will cause undue overlap of
engineering effort among the various groups. If this work is being done
elsewhere in the IETF, I will be more than happy to combine forces or
step aside if it will result in less code for all of us to write, deploy
and maintain.

> and no longer a fait accompli?

Check the archive, I posted it just recently.

> That is a red herring.  PPTP is still not widely used to handle the

Precisely. L2TP is not either. L2F, VTP and whatever Ascend/Lucent
(which actually may be PPTP come to think of it, I cannot remember now)
are likely the most widely used.

> packets over other arbitrary layers.

I never said it was. I said that L2TP has roots in tunneling more than
PPP. That's all. And that's true.

> one are good reasons to disband the working group sooner than later.

The alternative? No standard for what is now a highly deployed technique
for access on the Internet (that is, tunneling of PPP). The protocols in
place would likely be some version of L2F and PPTP, controlled largely
by the original companies deploying each (or what remains of them). We
would be writing new features and maintaining code for both, fighting
interoperabilty problems without a forum for testing and documenting
agreed upon methods, etc. Either this, or standardization under the
"L2TP Forum" or some other entity if we were lucky.

In fact, the WG probably stumbled in the past by NOT being more
open-minded. Experience tells me that thinking the WG has the power to
reduce writing of and deployment of code by telling people to "go away"
does not reduce the code I ultimately have to write and the number of
standards I have to support for essentially the same thing.

If someone is modifying L2TP for some other use, I want to know about
it. Period. I cannot think of a better place than here to discuss it as
these are the people that are going to have to write and support the
code.

I think we have spent enough of everyone's time on this thread now. I
hope that it at least served the purpose for people understanding where
I am trying to lead this group. Feel free to disagree, but from this
point on I ask you to take it to the next level rather than waste more
of our time here.

Thanks,

- Mark