Subject: Re: [MOBILE-IP] draft-ietf-mobileip-3gwireless-ext-04

From: "Lipford, Mark" <[email-masked]>
Date: Mon, 28 Aug 2000 08:35:16 -0500

Your rationale is correct.  This is to look beyond PPP as the framing, but
was developed to be more generic.  The first implementation of this will be
with PPP in a cdma2000 network for connection from the radio access network
to the PDSN.  I am sure there could be other implementations, but this is
all that we are aware of at this time.
Mark A. Lipford

                -----Original Message-----
                From:   Gopal Kailad [mailto:[email-masked]]
                Sent:   Saturday, August 26, 2000 12:38 AM
                To:     [email-masked]
                Subject:        [MOBILE-IP]
draft-ietf-mobileip-3gwireless-ext-04

                What is the rationale for choosing GRE instead of L2TP to
                tunnel PPP? It will be useful to add it to the draft.

                Since L2TP has call setup support, there would have been
                no need to overload the mobile IP registration mechanism
                to setup GRE tunnels. Also, L2TP has support for in order
                delivery using sequence numbers, and there would have been
                no need for adding sequence number support to GRE after it
                was deprecated.

                One possible advantage with GRE is future support for
tunneling
                IP instead of PPP, if the PDSN talks IP with the MN. Is
there
                any other benefit?

                This has probably been discussed in the mailing list, but
                I have been following this list only recently, and I could
                not get the rationale from the mailing list archives (may be
                I did not go back far enough!) Anyways I think this
                information is useful to have in the draft.

                Also, if GRE is going to be used to tunnel PPP, will escape
                characters, framing, and FCS be carried all the way to the
                PDSN?

                Cheers,

                Gopal