Subject: RE: [nemo] Re: Closing Issue 3

From: "Pascal Thubert (pthubert)" <[email-masked]>
Date: Tue, 29 Jul 2003 10:21:48 +0100

> -----Original Message-----
> From: Chan-Wah Ng [mailto:[email-masked]]
> Sent: mardi 29 juillet 2003 10:48
> To: Pascal Thubert (pthubert)
> Cc: Vijay Devarapalli; T.J. Kniveton; IETF NEMO WG
> Subject: Re: [nemo] Re: Closing Issue 3
> 
> Sorry for the mixed up, Pascal.  I will try harder ;), but not before
> the following doubts are answered.
> 
> On Tue, 2003-07-29 at 16:32, Pascal Thubert (pthubert) wrote:
> > My original take on July 16 was (REALLY) as follows:
> >
> > > I would have preferred a text saying that "the MR MUST keep all
> > > necessary information to clean up whichever routes it installed,
for
> > > instance by keeping the list of prefixES in BCE, whether they come
> > from
> > > implicit or explicit source".
> >
> 
> Is that "the MR MUST... " or "the HA MUST..."?
> 

Sure, sorry for the typo

> 
> > I still think it's sufficient and that it goes with the spirit TJ
> > proposed.
> >
> > Kent found that this text doesn't cover the case when routes need to
be
> > re-injected into the routing table. Kent answered with the text that
> > Vijay's assigning to me:
> >
> > "The Home Agent MUST keep all necessary information to be able to
add or
> > delete routes associated with the Mobile Router at the time.  For
> > instance, the list of Mobile Network Prefixes may be stored in the
> > Binding Cache entry."
> >
> > But this was not fully correct because the BCE data is transient.
> >
> By BCE is transient, I presume you meant that BCE entry will expire
> according to lifetime field in the BU or BA message.  Why should this
be
> a problem?  If the MR is alive and still attached to the global
network,
> it would have sent a refresh or updated BU containing the prefix
> (assuming that is how it injected routes) before the BCE expires.  If
> the HA does not receive the BU by the time the corresponding BCE
> expires, the HA would have to assume that the MR is no longer
> reacheable, and should delete the dynamic routes anyway,

Agreed

Kent wanted to make sure that when the routes are removed (say lifetime
expires) then the HA will be able to reinstall them upon a new binding
from that MR. As you say, this is not a real problem. An oter wording
for the same answer is that whatever the HA used the first time can be
used again (implicit with prefix table or explicit)

Pascal

---

From: Chan-Wah Ng <[email-masked]>
Date: 29 Jul 2003 19:18:07 +0800

Ok, let me try this again.

Objective is:

(1) to state that HA MUST maintain all information necessary for it to
clean up routes that are injected by the MR through the bi-directional
tunnel, or through a binding update (be it implicit or explicit), when
parameters of the bi-directional tunnel is changed.

(2) not be too vague: Quoting Vijay: "what information? where do you
store this information? which data structure?"

This is what I come up with:

        The home agent MUST maintain all information necessary for it to
        clean up routes that are injected by the MR through the
        bi-directional tunnel, or through a binding update, when the
        bi-directional tunnel is tore down or the end-point(s) of the
        bi-directional tunnel has changed.  For instance,  For instance,
        the home agent MAY keep the list of prefixes in BCE, whether
        they come from implicit or explicit source, so that routes
        corresponding to these prefixes can be deleted when the BCE
        expires or is deleted.

How about this?

/rgds
/cwng

---

From: Chan-Wah Ng <[email-masked]>
Date: 29 Jul 2003 19:18:07 +0800

Objective is:

How about this?

/rgds
/cwng

---

From: Vijay Devarapalli <[email-masked]>
Date: Tue, 29 Jul 2003 10:39:19 -0700

I probably forgot to tell you that the text I 
proposed was going into section 6.1.1 of the 
latest spec
http://people.nokia.net/vijayd/nemo/draft-ietf-nemo-basic-support-pre01.txt.

binding cache as a conceptual data structure 
is described in the MIPv6 spec. I just wanted 
to mention how NEMO extends it. the prefix 
information needs to stored in it in case the 
Binding Update (which created this BCE) 
contained prefix information in explicit mode.

so the following text really doesnt fit under 
that section.

also remember that under section 6.7 (Mobile 
Network Prefix De-Registration) we have the 
following text.

   In addition, the Home Agent also removes the bi-directional tunnel
   and stops forwarding packets to the mobile network.

Vijay

---

From: Vijay Devarapalli <[email-masked]>
Date: Tue, 29 Jul 2003 10:39:19 -0700

Vijay