Subject: [mobile-ip] HA registration

From: Mikko Särelä <[email-masked]>
Date: Mon, 7 Oct 2002 11:14:47 +0300 (EEST)

I'm reading through the MIPv18-draft and trying to get an understanding on
the following problem. 

When a node decides to become mobile and leave it's home network, how does
it gain itself HA? 

Does it just move out of the home network and then start Binding Update
procedure (from the HA list it hopefully has gathered from Local Router
Advertisement messages, or is there some way it can assure itself a HA
before leaving the Home Network?

Also in 11.6.6 'Forwarding from a Previous Care-of-Address' there seems to
be an inconsistency due to version updates (I believe). 

   This Binding Update is sent to a home agent, albeit a temporary
   one.  Nevertheless, the authentication requirements for Binding
   Updates from a mobile node to its home agent apply, as specified in
   Section 11.6.1.

It seems that the authentication requirements have been moved to section
5.1 Binding Updates to Home Agents. My suggestion is to change the above
paragraph to correspond this change

   This Binding Update is sent to a home agent, albeit a temporary
   one.  Nevertheless, the authentication requirements for Binding
   Updates from a mobile node to its home agent apply, as specified in
   Section 5.1.

- Mikko Särelä

---

From: "Brijesh Kumar" <[email-masked]>
Date: Mon, 7 Oct 2002 12:19:44 -0700

I was reading <draft-ietf-mobileip-vpn-problem-statement-req-00> yesterday,
and I have a few comments with regards to the example roaming scenario in
the draft for the authors.

1. First, the  "Dr. Joe in the hospital" case example is somewhat
misleading. A few years ago, I was involved in a project that proposed the
use of bluetooth in  hospitals, and the project has to be abandoned because
hospitals apparently had a blanket ban on the use of any wireless device
including cellphones and 2-way pagers in the premises. The question of
hypothetical Dr. Joe using 802.11 wireless device in an hospital and being
able to carry his transport sessions between lab to his office is out of
question. The example should be replaced with a realistic example, if you
need one at all.

2. My main question relates to finding out a real and useful application
based on scenario discussed in the draft (section 2.1), i.e., the FA is in
the public domain and the HA is behind the firewall and the VPN gateway. The
technically scenario is fine, but I am having difficulty in finding any real
application that would need any thing other than an IPSEC VPN tunnel from a
mobile device. Afterall, all of us do use VPNs and corporate applications
from hotels and airports, and also, in somecases, do NAT traversal with
IPSEC clients. Why does someone need  IPv4 mobility when he has access to
the office VPN and can use all applications.  What appplications are
depenedent on the ability to maintain IP address mobility via home agent?
This question is not answered in the draft. Just saying Dr. Joe would "like
to maintain his transport connection" is not sufficient since it is not
clear why he needs this (afterall, it requires one extra layer of ipsec
tunnel)? Also, it is quite unlikely that transport connection will survive
visit from his hospital to the hot-spot. (voice calls over ip aren't useful
application because cell phones aren't going to be out of fashion and
replaced by ip phone calls any time soon.). Will it not be interesting  to
first find a useful application, before discussing the solution?

3. Also perhaps draft should have references to basic NAT traversal drafts -
IPsec-NAT Compatibility Requirements <draft-ietf-ipsec-nat-reqts-02.txt> and
<Negotiation of NAT-Traversal in the IKE draft-ietf-ipsec-nat-t-ike-03.txt>

Cheers,

--brijesh

---

From: Jari Arkko <[email-masked]>
Date: Sun, 13 Oct 2002 14:32:48 +0300

> before leaving the Home Network?

What does 'assure' mean? It has learned a number of HAs it could use
from the local router advertisements. In addition it must have pre-arranged
some security association with the home agent(s), typically by talking with
the administrator.

>    Updates from a mobile node to its home agent apply, as specified in

Right, but 11.6.6 and the functionality talked inside it has been
moved out of the base spec.

Jari