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

["Taewan You" <[e-mail]>]

Dear Thierry & all,

For your comment of general network issues in this draft
(draft-hong-multipleif-mn-pb-statement-00.txt), I have a comment. Please
read inline.

Thanks,
Best Regards,
Taewan You.

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf
> Of Thierry Ernst
> Sent: Wednesday, October 26, 2005 6:51 PM
> To: Monami6 WG
> Cc: [e-mail]
> Subject: Re: FW: [Monami6] FW:I-DACTION:draft-hong-multipleif-mn-pb-
> statement-00.txt
> 
> 
> 
> 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).

Even though this problem that end node should update the relation between
destination address and specific network interface to prevent dissonance
between active network interface and changed IP address was happened in
fixed end node, I do not agree that the SHIM6 should qualify this problem.

AFAIK, SHIM6 is considering environment where an end node has multiple paths
(multiple IPv6 address prefix) by connecting to different ISP that means
site multihoming. So site multihomed an end node does not have necessarily
multiple interfaces and it only has to obtain multiple addresses from
different site exit routers. But the mobile node equipped multiple
interfaces are down for discussion in MONAMI6 WG clearly.

Therefore, if we have consensus, which this problem must be solved for using
multiple interfaces, I think that the MONAMI6 is more suitable place than
SHIM6.

> 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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