Subject: RE: [nemo] My simple thoughts on HAHA

From: "Pascal Thubert \(pthubert\)" <[email-masked]>
Date: Thu, 18 Nov 2004 13:43:56 +0100

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf
Of Alexandru Petrescu
> Sent: jeudi 18 novembre 2004 10:51
> To: Ryuji Wakikawa
> Cc: [email-masked]
> Subject: Re: [nemo] My simple thoughts on HAHA
> 
> Hello Ryuji, thanks for your remarks.  I have some remarks, see below.
> I agree with you half half.
> 
> Ryuji Wakikawa wrote:
> > Alexandru Petrescu wrote:
> >
> >> HAHA is a method for MR to change its HA from a remote one to a
> >> closer one.  It implies that paths from CN to MR's HoA are changed
> >>  from reaching the oldHA to reaching the newHA.  These changes are
> >>  presumably done with a dynamic routing protocol.  HAHA also
> >> involves synchronizing the BCs of the two HAs such as to both know
> >>  the current MR's CoA.
> >
> > I believe you read the global-HAHA draft.
> 
> Yes.  I think my remarks pertain to both drafts (HAHA and global
HAHA).

Surprisingly enough, this is not at all what the global HAHA draft says.
The draft says that the CN reaches Home via the closest point of
presence, so if CN does not move, then this does not change. MR keeps
its MNP, and the MNP information is distributed by a routing protocol
over a mesh of tunnels between HAs. The CN is not supposed to see the MR
HoA (it's just a binding ID), unless it is formed from the MNP. The
whole concept of Home link is gone. 

Maybe a second reading?

Pascal

---

From: Alexandru Petrescu <[email-masked]>
Date: Thu, 18 Nov 2004 14:00:15 +0100

Pascal Thubert (pthubert) wrote:
>>>>  closer one.  It implies that paths from CN to MR's HoA are 
>>>> changed from reaching the oldHA to reaching the newHA.  These 
>>>> changes are presumably done with a dynamic routing protocol. 
>>>> HAHA also involves synchronizing the BCs of the two HAs such as
>>>>  to both know the current MR's CoA.
>>> 
> Surprisingly enough, this is not at all what the global HAHA draft 
> says. The draft says that the CN reaches Home via the closest point 
> of presence, so if CN does not move, then this does not change. MR 
> keeps its MNP, and the MNP information is distributed by a routing 
> protocol over a mesh of tunnels between HAs.

I do not see how MNP valid at one site can be advertised by another
site, even if it is requested to do so by the routing protocol that runs
over the mesh of tunnels between HAs.

I mean, if site1 advertises MNP to the Internet and oHA is in this
site1, then it is impossible for site2 to advertise the same MNP to the
Internet, even if oHA asks nHA (in site2) to do so, asked via a tunnel.

_If_ it were possible for site2 to advertise this same MNP once MR 
changed its HA, then there were no need of Mobile IP at all (and no need 
of tunneling HA to MR and no unoptimal paths).  Do you kind of half 
agree with this?

> The CN is not supposed to see the MR HoA (it's just a binding ID), 
> unless it is formed from the MNP.

I think there are too many things forced at once.  I don't understand 
what is a binding ID and I don't see how the HoA of MR is formed from 
the MNP (other than a specialized need).

> The whole concept of Home link is gone.

I have difficulty grasping the fact that the whole concept of the Home 
link is gone.

> Maybe a second reading?

I can do that.

I am sure also that you will indicate that I should read the Home 
Network Models, which is a WG item, and which I've already read and that 
I've remarked on.  I can do that too.

Alex

---

From: Christophe Janneteau <[email-masked]>
Date: Fri, 19 Nov 2004 11:01:45 +0100

Ryuji, Pascal, Alex,

Sorry to jump into the discussion....

> whole concept of Home link is gone. 

In my understanding of HAHA, several HAs will annouce a route in an 
_internetwork_ to the same MNP. The packet sent by CN (addressed to a 
node of MNP) will reach the closest HA (e.g. HA annoucing MNP with the 
smallest metric). And HA will tunnel the packet to MR. Correct?

Now the question is: what type of internetwork are we talking about?
1- The global Internet?, or
2- Only a site? in which case all HA would belong to the same site, and 
there would be only one route advertised from the site gateway to the 
Internet.

I think 1 would be an issue, especially for IPv6 (see multi6 work). No?

In other words, what are the realist deployement scenarios targeted by 
the draft?

Thanks
Christophe