Subject: Re: ppp multiplexing over p-to-p links

From: Vernon Schryver <[email-masked]>
Date: Sat, 16 Oct 1999 09:04:58 -0600 (MDT)

> To: Juha Heinanen <[email-masked]>, [email-masked]
> From: "Karl Fox" <[email-masked]>

> At 03:13 AM 10/16/99 , Juha Heinanen wrote:
> >when a ras is connected to an isp router over a point-to-point link such
> >as a tdm circuit or an atm or fr vc, using l2tp for multiplexing several
> >ppp sessions over this link seems like a big overkill.  has there been
> >any discussion on defining a simple ppp multiplexing protocol for that
> >purpose?  what would be the arguments for not doing so?

> One would be that we already have something that works.

Why would you use L2TP?  Why not the old standby of IP encapsulated in
the old familiar ways in ATM or FR circuits?  Isn't IP exactly a "simple
multiplexing protocol"?  (I'm assuming that the ultimate user traffic is
also IP.)

Or if the idea is use a simple PPP multiplexing protocol to get the
component PPP links of a multilink PPP bundle to the ISP, the sad truth
is that is exactly the design goal of L2TP.  That L2TP is not very simple
is testimony to the usual effects, both good (dealing with reality) and
otherwise (freaping creaturism and committee politics).  You can be
confident that a new IETF version of L2TP would be simpler in the same
way that SNMPv2 is simpler than SNMPv1, ESMTP is simpler than SMTP, SSH
is simpler than rlogin, BGP4 is simpler than EGP, and so on.

Vernon Schryver    [email-masked]

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From: "Karl Fox" <[email-masked]>
Date: Sat, 16 Oct 1999 11:37:02 -0400

At 11:04 AM 10/16/99 , Vernon Schryver wrote:
>the old familiar ways in ATM or FR circuits?

Oh.  Of course, that would be simpler.  I was assuming a single VC was all 
that was available.

Karl Fox <[email-masked]>
Key fingerprint = 5B15 7260 D55E D680 0B93  4953 8A3B AB0E C05D 77A3

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From: Juha Heinanen <[email-masked]>
Date: Sun, 17 Oct 1999 08:18:23 +0300 (EEST)

> Oh.  Of course, that would be simpler.  I was assuming a single VC was all 

yes, single vc carrying multiple parallel ppp sessions, one per dialup
user.  none of capabilities of l2tp apart from multiplexing are not
needed in this application.  also ip sunneling is unnecessary, since the
ras and the isp router are directly connected over the vc.

if you take all the discovery and service selection stuff out from pppoe
you pretty much get what would be needed.

-- juha