Subject: Re: PPP L2TP legal status

From: William Allen Simpson <[email-masked]>
Date: Fri, 03 Jan 2003 13:54:32 -0500

James Carlson wrote:
> 
> Glen Zorn writes:
> > L2TP is is sole subject of RFC 2661.  Cisco holds no IPR WRT L2TP, nor does
> > it license it to or from anybody.
> 
> I would very much like to hear a clear statement from Cisco's lawyers
> on this subject.  The last such public communication that I know of
> was this one:
> 
>         http://www.ietf.org/ietf/IPR/CISCO-L2TP
> 
> This certainly leaves the situation a lot less clear than you seem to
> be indicating, at least to me.
> 
> For what it's worth, I personally know several folks who've been
> contacted by lawyers involved in L2TP IPR litigation (including
> myself), and who are thus quite adverse to implementing any part of
> that standard for that reason.  Talking to lawyers about IPR is not an
> enjoyable part of the job.  If Cisco is not pursuing these claims,
> then I think that'd be wonderful news to make known more widely so
> that the standard can become more widely used.
> 
I believe that it is public knowledge (and not in violation of any NDA) 
that Cisco has been pursuing claims against Alcatel for over 3 years now.  

The case has passed factual discovery, is in expert depositions, and is 
expected to go to trial in the near future. 
-- 
William Allen Simpson
    Key fingerprint =  17 40 5E 67 15 6F 31 26  DD 0D B9 9B 6A 15 2C 32

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From: Dennis Ferguson <[email-masked]>
Date: Fri, 03 Jan 2003 12:54:34 -0800

Frank Cusack wrote:
> On Fri, Dec 27, 2002 at 10:00:33PM -0500, Barney Wolff wrote:
> > On Fri, Dec 27, 2002 at 06:45:10PM -0800, Frank Cusack wrote:
> > > 
> > > PPTP is not proprietary.  L2TP is, though.
> > 
> > You seem to have a very odd definition of proprietary.  Both protocols
> > are published, but PPTP is strictly under Microsoft's control, while
> > L2TP is a standards-track IETF effort.  If sourceforge is your criterion,
> > both protocols are there.
> 
> Yes, I guess I'm using a different (incorrect) definition of proprietary.
> What I really meant was, PPTP is freely implementable.  L2TP is not.
> 
> I can write and publish an implementation of PPTP, without being beholden
> to Microsoft whereas I must license L2TP from Cisco.  Of course, please
> correct me if Cisco has granted no-cost license terms to anyone for L2TP.

I don't think the latter paragraphs describe the situation.  Cisco has
a patent which mentions neither PPTP nor L2TP, but which patents an
application for which either PPTP or L2TP might be used.  As such the
patent, if it applies at all, applies equally to PPTP and L2TP when
either is used for the application described in the patent's claims.
PPTP is no less encumbered by this patent than L2TP.

What this amounts to is that if your use of PPTP doesn't infringe on this
patent then using L2TP for the same thing won't either, while if your
use of L2TP does infringe on this patent then changing the protocol
to PPTP won't save you.  The patent provides no particular reason to
prefer one protocol over the other since, for applications which
infringe the patent, the patent will apply equally to both PPTP and
L2TP.

If I had to guess (I'm far from a lawyer) I suspect the patent claims
apply not at all when the implementation does what RFC 3193 defines to
be "Voluntary Tunneling", with the (LAC,PAC) residing on the client
machine, but may apply when the implementation does "Compulsory
Tunneling" with the LAC residing in the NAS.  I suspect part of
the confusion with respect to applicability of the patent may be that
PPTP has seen the most use in the former application while L2TP has
seen greater use in the latter application, but this should not be
construed to mean there is something wrong with L2TP with respect
to that patent which isn't wrong with PPTP.

With respect to Cisco revealing that it may have IPR related to
L2TP, but failing to make the same assertion with respect to PPTP,
do not mistakenly take this to mean that Cisco thinks it has IPR
related to L2TP but not to PPTP.  The IETF only requires IPR
disclosure when the owner of the IPR (or its employees) participates
in the standard development.  Since Cisco wasn't involved with
the development of PPTP it had no requirement to disclose any IPR
which might relate to that protocol even if Cisco felt it had
some.  If anything Cisco's disclosure is of (small) benefit to
L2TP, since for L2TP they've at least asserted that they'll
license the patent under openly-specified, reasonable and
non-discriminatory terms, while for PPTP they are free to
license the patent under secret, unreasonable or discriminatory
terms, or not at all, if they choose.

It is getting progressively harder to do anything at all without
the risk of running afoul with someone's lawyers, but in this case
I don't think either of these protocols has either advantage or
disadvantage with respect to the IPR we know about.  If your
use of L2TP would infringe on this patent then using PPTP for
the same thing would also infringe, so you might as well disregard
this altogether when choosing between the protocols for a particular
application.  They are both equally (un)encumbered.

Dennis Ferguson

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From: Frank Cusack <[email-masked]>
Date: Sat, 4 Jan 2003 01:50:20 -0800

On Fri, Jan 03, 2003 at 12:54:34PM -0800, Dennis Ferguson wrote:
> Tunneling" with the LAC residing in the NAS.

Is it possible to implement a LNS which can only terminate voluntary
mode tunnels?

> the risk of running afoul with someone's lawyers

:~(

/fc

---

From: "Glen Zorn" <[email-masked]>
Date: Sat, 4 Jan 2003 12:15:44 -0800

> > the risk of running afoul with someone's lawyers

As I understand it, it's actually very easy to avoid running afoul of
Cisco's patent lawyers: just don't sue Cisco over your own IPR.  I am
obviously not a lawyer, either., but AFAIK Cisco only uses its patents in a
defensive manner, as is the case w/Alcatel.