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

From: Gopal Kailad <[email-masked]>
Date: Sat, 26 Aug 2000 01:37:47 -0400

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