Re: FW: [Monami6] FW: I-DACTION:draft-hong-multipleif-mn-pb-statement-00.txt

[Thierry Ernst <[e-mail]>]

Hi,

Comments inline, but first, I would like to point out that a new version
of draft-montavont-mobileip-multihoming-pb-statement (i.e. -05) has been
sent Monday, but not yet announced (we hope it to be renamed to
draft-montavont-monami6-multihoming-pb-statement)

Here is the link:
http://www.nautilus6.org/doc/drafts/draft-montavont-monami6-multihoming-pb-statement-05.txt
http://www.nautilus6.org/doc/drafts/draft-montavont-monami6-multihoming-pb-statement-05.html


On Wed, 26 Oct 2005 15:23:17 +0900
"Yong-Geun Hong" <[e-mail]> wrote:
> I was asked to send the review and difference between 
> draft-montavont-mobileip-multihoming-pb-statement-04.txt and
> my draft by Nicolas.
> 
> I think that the draft
> draft-montavont-mobileip-multihoming-pb-statement-04.txt 
> is a good draft which describes the requirements from the point of
> view of multihomed mobile nodes operating Mobile IPv6 and defines some
> issues. We also learn many things in this draft.

Thanks.

> But, when we were implementing a multiple interfaces mobile
> node(mobile router),
> we thought that the draft do not perfectly handle the problems of
> multiple interfaces
> of a mobile node. 

Well, I have to admit our draft is not perfect and that it will deserve
more work. Any specific suggestions on how to improve it will be
welcome. 

> I summarize the parts related to the issues of multiple interfaces in
> a mobile node
> within the draft
> (draft-montavont-mobileip-multihoming-pb-statement-04.txt)
> 
> =============================================================
> 
> 1. Section 3. Requirements 
>     3th paragraph [page 8] : 
> 
>    Basically, Internet connectivity is guaranteed for a MN as long as
>    at least one path is maintained between the MN and the fixed
>    Internet. In some cases, it may be necessary to divert packets from
>    a (perhaps failed) path to an alternative (perhaps newly
>    established) path (e.g. for matters of fault recovery,
>    preferences), or to split traffic between multiple paths (e.g. for
>    load sharing, load balancing).  The use of an alternative path must
>    be transparent at layers above layer 3 if broken sessions and the
>    establishment of new transport sessions has to be avoided.
> 
> 2. Section 3. Requirements 
>     Last paragraph [page 9] :
> 
>   One has to consider whether these goals can be achieved with
>    transparency or without transparency.  Transparency is achieved
>    when switching between interfaces does not cause the disruption of
>    on- going sessions.  To be achieved with transparency, a necessary
>    (may or may not be sufficient) condition is for the end-point
>    addresses to remain unchanged.  This is in-view of the large amount
>    of Internet traffic today are carried by TCP, which unlike SCTP,
>    cannot handle multiple end-point address pairs.
> 
> 3. Section 5.6 (n, 1, n) : n ifaces, 1, HoA, n CoAs
> 
> 4. Section 6.1.3 Media Detection 
> 
> 5. Section 7.3 Flow redirection
> 
> =============================================================
> 
> In my draft, I describe some practical problems.
> 
> 1. Mobile IPv6-specific Issues
>  : When a mobile node has multiple interfaces, it must have the
>  ability to
> look at
>   all RA messages from multiple network interfaces to determine
>   network
> movement.

The problem you describe in your draft is an implementation specific
issue, as pointed out by Romain Kuntz.

In draft-montavont, we have a section "considerations for MIP6
implementation". So, at best some text could be added there.

> 2. General network Issues
>  : The mobile node also must update the relation between a destination
> address and
>   a network interface when it changes a network interface.

The problem yoiu describe in your draft is related,  when considering a
mobile node, to  the HoA address, and you ranged it into a "generic
issue" because it can apply to a fixed node with multiple interfaces,
right?  I think this is a problem in which SHIM6 is qualified (how
to change the locator, but not the identifier). 

I agree that our text in draft-montavont should be improved in a fashion
similar to draft-ietf-nemo-multihoming-issues where such issues are
well described. 


> 3. Considerations for Heterogeneous Environments
>  : For the mobile node in IPv4 based network
> 
> Although the
> draft(draft-montavont-mobileip-multihoming-pb-statement-04.txt) covers
> the multihoming issues including multiple interfaces node, my draft is
> more focusing on
> multiple interfaces node.

The concern described in your draft is valid and is addressed
in draft-ietf-mip6-nemo-v4traversal-00.txt. 

Note that I do not consider it has a multihoming issues at all: it is
right that nodes equipped with multiple interfaces may be more concerned
with this issue, but this could also happen for a node with a single
interface (for instance, a node with a WI-FI interface roaming between
an IPv6 wireless LAN and an IPv4 wireless LAN. We already came across
this problem.


> We think that it is better to make another document for considering
> multiple interface node.
> The problem of multiple interfaces is not only in network layer or
> Mobile IPv6 (NEMO) but also
> in below layer (layer 2). Like Link-layer Event Notification in DNA
> WG, it is better to consider
> link-layer to make perfect monami6 solutions.

Actually, I kind of agree that more text could be useful in
draft-montavont., in the same fashion as in
draft-ietf-nemo-multihoming-issues under the issue "Media Detection".
However, I think we disagree on the classification as I wouldn't
consider it as a MIP6-specific issue.

Thierry.


> > -----Original Message-----
> > From: [e-mail] 
> > [mailto:[e-mail]] On Behalf Of Yong-Geun Hong
> > Sent: Monday, October 24, 2005 10:39 AM
> > To: [e-mail]
> > Subject: [Monami6] FW: 
> > I-DACTION:draft-hong-multipleif-mn-pb-statement-00.txt 
> > 
> > 
> >  
> > Folks..
> > 
> > We have submitted an internet drat on analysis of multiple 
> > interfaces in a mobile node to monami6 WG. You can find the 
> > draft in the following link.
> > http://www.ietf.org/internet-drafts/draft-hong-multipleif-mn-p
> > b-statement-00
> > .txt
> > 
> > Abstract:
> > 
> >    This document is an analysis of multiple interfaces in a 
> > mobile node
> >    using Mobile IPv6 or a mobile router using NEMO Basic Support. 
> >    The current Mobile IPv6 and NEMO Basic Support are suitable 
> > for a single
> >    network interface.  When a mobile node or a mobile router has
> >    multiple interfaces, the current Mobile IPv6 and NEMO Basic
> >    Support cannot directly be used for them.  In this document, we 
> > describe some
> >    problems for a mobile node which has multiple network 
> > interfaces when
> >    the mobile node is using Mobile IPv6 as an aspect of a node.
> > 
> > 
> > We have researched the interworking between CDMA and WLAN and 
> > have implemented a mobile node using Mobile IPv6 and a mobile 
> > router using NEMO Basic Support with one CDMA network 
> > interface and one WLAN network interface. During this 
> > research and implementation, we have met some problems and 
> > described them in that draft.
> > 
> > Welcome any question and any comments.
> > 
> > Thanks..
> > 
> > Yong-Geun..

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