Subject: RE: [nemo] Re: Question-HAHA

From: "Pascal Thubert \(pthubert\)" <[email-masked]>
Date: Fri, 16 Apr 2004 12:39:42 +0100

Hi:

It depends on the model. If the MR takes its home address from its MNP then it does not need to. If the Home address is from a home link, then it needs to change if it takes a home agent on a different home link. This may happen in the case of Home Agent Global Distribution with the HAHA protocol.

Pascal

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf Of Mazen TLAIS
> Sent: vendredi 16 avril 2004 11:10
> To: [email-masked]
> Subject: [nemo] Re: Question-HAHA
> 
> In some drafts they propose to change mobile node's
> Home Agent (or the primary home Agent in
> HA-HA protocol).
> 
> I read many documents on the nemo support but I could
> not answer this question :
> 
> when a mobile node changes its home Agent does it have
> to change moreover its home address ?
> 
> 
> 
> 
> 
> 
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From: Alexandru Petrescu <[email-masked]>
Date: Fri, 16 Apr 2004 18:33:41 +0200

Pascal Thubert (pthubert) wrote:
> It depends on the model. If the MR takes its home address from its 
> MNP then it does not need to. If the Home address is from a home 
> link, then it needs to change if it takes a home agent on a different
>  home link. This may happen in the case of Home Agent Global 
> Distribution with the HAHA protocol.

Right, and in all the above cases all app-level communications running
on MR or LFN will be interrupted when MR changes its HA, right?

Alex

---

From: Alexandru Petrescu <[email-masked]>
Date: Fri, 16 Apr 2004 18:33:41 +0200

Alex

---

From: "Jee J.Z." <[email-masked]>
Date: Fri, 18 Jun 2004 18:23:14 +0100

> Right, and in all the above cases all app->level communications running
> on MR or LFN will be interrupted when MR >changes its HA, right?

Why will all communications (running on MR or LFN) be interrupted in the
first case (the MR does not need to change its home address)?

Moreover, in the second case (the MR needs to change its home address), why
will communications running on LFN be interrupted?

Jee

---

From: "Jee J.Z." <[email-masked]>
Date: Fri, 18 Jun 2004 18:23:14 +0100

Jee

---

From: Alexandru Petrescu <[email-masked]>
Date: Fri, 16 Apr 2004 23:30:22 +0200

Jee J.Z. wrote:
>>> It depends on the model. If the MR takes its home address from 
>>> its MNP then it does not need to. If the Home address is from a 
>>> home link, then it needs to change if it takes a home agent on a
>>>  different home link. This may happen in the case of Home Agent 
>>> Global Distribution with the HAHA protocol.
>> 
>> Right, and in all the above cases all app->level communications 
>> running on MR or LFN will be interrupted when MR >changes its HA, 
>> right?
> 
> Why will all communications (running on MR or LFN) be interrupted in
>  the first case (the MR does not need to change its home address)?

Because one can not have the same Home Address topologically correct at
two different Home Agents that sit on different links (links separated
by routers), right?

> Moreover, in the second case (the MR needs to change its home 
> address), why will communications running on LFN be interrupted?

Because the address of the LFN is derived from a prefix that is
topologically correct at only one HA, and that prefix can not be
topologically correct at another HA that sits on a different link (links
separated by routers), right?

On another hand, if it is assumed somehow that a MNP prefix or a Home
Address can be made topologically correct at two distinct places in the
network mesh (like with multi-homing or something) then no Mobile IPv6
is needed at all to tunnel traffic from a Home Address to a Care-of
Address, because the Care-of Address is, in fact, the Home Address
itself that was made topologically correct everywhere, no?

Alex

---

From: Alexandru Petrescu <[email-masked]>
Date: Fri, 16 Apr 2004 23:30:22 +0200

Alex

---

From: "Jee J.Z." <[email-masked]>
Date: Sat, 19 Jun 2004 00:31:33 +0100

> two different Home Agents that sit on different links (links separated

If it's the case, why can the MR keep its home address unchanged as what
Pascal has mentioned? I assume the MR can have the same home address because
the two HAs are on the same link.

> separated by routers), right?

Isn't the HA of a LFN independent with the HA of its MR (please correct me
if not)? I mean whether the home address of the MR changes or not, the home
address of the LFN does not need to change, which means the communication
session between the LFN and a CN will not be broken.

> itself that was made topologically correct everywhere, no?

IMHO, MNP prefix could be made topologically correct at two distinct places
(please correct me if not), while home address can only be topologically
correct on the same link.

Regards,
Jee

---

From: "Jee J.Z." <[email-masked]>
Date: Sat, 19 Jun 2004 00:31:33 +0100

Regards,
Jee

---

From: Alexandru Petrescu <[email-masked]>
Date: Sun, 18 Apr 2004 01:18:06 +0200

Jee J.Z. wrote:
>>>>> It depends on the model. If the MR takes its home address 
>>>>> from its MNP then it does not need to. If the Home address is
>>>>>  from a home link, then it needs to change if it takes a home
>>>>>  agent on a different home link. This may happen in the case
>>>>>  of Home Agent Global Distribution with the HAHA protocol.
>>>> 
>>>>  running on MR or LFN will be interrupted when MR >changes its
>>>>  HA, right?
>>> 
>>> Why will all communications (running on MR or LFN) be interrupted
>>>  in the first case (the MR does not need to change its home 
>>> address)?
>> 
>> Because one can not have the same Home Address topologically 
>> correct at two different Home Agents that sit on different links 
>> (links separated by routers), right?
> 
> If it's the case, why can the MR keep its home address unchanged as 
> what Pascal has mentioned?

I don't know.

> I assume the MR can have the same home address because the two HAs 
> are on the same link.

When the HA's are on the same link then there is another mechanism
defined by Mobile IPv6 by which the MR may choose among several HA's on
the home link.

>> topologically correct at another HA that sits on a different link 
>> (links separated by routers), right?
> 
> Isn't the HA of a LFN independent with the HA of its MR (please 
> correct me if not)?

LFN has no HA since it's fixed and runs no Mobile IPv6.  When packets
from CN are addressed to CN then it's MR's HA that intercepts these
packets and forwarded/tunnelled to the MR's CoA.  In this sense, one may
say that MR's HA is the same as LFN's HA, although it's not quite
correct since LFN does not do any Mobile IPv6.

> I mean whether the home address of the MR changes or not, the home 
> address of the LFN does not need to change,

This is correct, I understand that.

> which means the communication session between the LFN and a CN will 
> not be broken.

Comm from CN to LFN must be intercepted by MR's HA in order to be
forwarded to current position of MR and further to LFN.  So, LFN's
address must be topologically correct at MR's HA (in practice, LFN's
address is derived from MNP and MNP is topologically correct at HA).
And, because the MR's home address can not be topologically correct at
two different HA's the same MNP can not be either; so it's because the
MR's HoA changes that CN-LFN comms are interrupted (not because the MR's
CoA changes).

> IMHO, MNP prefix could be made topologically correct at two distinct
>  places (please correct me if not),

Please tell me how the MNP prefix is made topologically correct at two
distinct places in the network (places separated by routers), and then
I'll tell you why Mobile IP is not needed in that case.

> while home address can only be topologically correct on the same 
> link.

I think that if a unique MNP is valid at two different nets then a full
/128 address can be made so too.

Alex

---

From: Alexandru Petrescu <[email-masked]>
Date: Sun, 18 Apr 2004 01:18:06 +0200

I don't know.

Alex

---

From: "Jee J.Z." <[email-masked]>
Date: Mon, 21 Jun 2004 16:19:06 +0100

Hi Alex,

I get more clear on the issue after reading Pascal's explanations. Below
inline is what I wrote and thought before Pascal's email, which sounds quite
limited and could be flawed, and the HAHA protocol seems to have covered all
I had thought of -- I'd better read it through.

> > what Pascal has mentioned?

So this issue is still pending?

> defined by Mobile IPv6 by which the MR may choose among several HA's on

Yes, but aren't we talking about handover among these HA's? For load
balancing purpose, I think the MR may choose to handover to a new HA on the
same link as the previous HA, so it can keep its home address unchanged. Do
you mean this handover does not in the scope of HAHA? I can't think of MIPv6
can manage HA handover.

> correct since LFN does not do any Mobile IPv6.

Thank you. That's my confusion on definitions.

> MR's HoA changes that CN-LFN comms are interrupted (not because the MR's

OK, I understand now.

> I'll tell you why Mobile IP is not needed in that case.

OK. Well, actually I am thinking whether MNP handover is possible. Say there
are two HA's on different links. Both of them could advertise the
reachability of an aggregation of the MR's MNP. When the MR selects one of
the two HA's (say HA1), HA1 assigns the MNP to the MR and does the
redirection job for the MNP; when the MR decides to change its HA to HA2,
the MNP is handed over to HA2, and HA2 manages the MNP and does the
redirection job. However, because the two HA's are on different links, the
home address of the MR has to change.

Regards,
Jee

---

From: "Jee J.Z." <[email-masked]>
Date: Mon, 21 Jun 2004 16:19:06 +0100

Hi Alex,

OK, I understand now.

Regards,
Jee

---

From: Ryuji Wakikawa <[email-masked]>
Date: Fri, 23 Apr 2004 00:42:58 +0900

At Fri, 16 Apr 2004 18:33:41 +0200,
Alexandru Petrescu wrote:
> 
> [1  <text/plain; us-ascii (7bit)>]

Not true on the HAHA protocol.

For example, if MR's MNP is managed as part of aggregated prefix, MR
can switch any of HAs that serve the aggregated prefix without any
interruption of CN-LFN communication.

regards,
ryuji

---

From: Ryuji Wakikawa <[email-masked]>
Date: Fri, 23 Apr 2004 00:42:58 +0900

regards,
ryuji

---

From: Ryuji Wakikawa <[email-masked]>
Date: Fri, 23 Apr 2004 01:18:18 +0900

Hello Jee and Alex

At Mon, 21 Jun 2004 16:19:06 +0100,
> I had thought of -- I'd better read it through.

We understood that the current HAHA draft is a bit hard to understand
all conepts, because we put many things in the single draft. We are
currently working on updates of HAHA. Pleas wait for a while to find
the better version:-).  And we really appreciate your comments on the
HAHA draft.

> So this issue is still pending?

Which issue? When HoA is retrieved from MR's MNP, HoA is never changed
unless MNP is changed. Whether MNP can change its serving HA is
another problem. This is addressed by pascal's nemo-usage draft and HAHA.

> you mean this handover does not in the scope of HAHA? I can't think of MIPv6

It is in the scope of HAHA. 

> > MR's HoA changes that CN-LFN comms are interrupted (not because the MR's

LFN is not aware of HoA's change as long as MNP is not changed. 

> home address of the MR has to change.

It's possible. The point is whether we can allow HoA<->MNP
relationship dynamically. My answer is yes with pascal's nemo-usage
and HAHA protocol.  please check fig2 and appendix of the haha draft.

ryuji

---

From: Ryuji Wakikawa <[email-masked]>
Date: Fri, 23 Apr 2004 01:18:18 +0900

Hello Jee and Alex

ryuji

---

From: Mazen TLAIS <[email-masked]>
Date: Thu, 22 Apr 2004 18:44:43 +0200 (CEST)

Ryuji Wakikawa <[email-masked]> wrote:
 
At Fri, 16 Apr 2004 18:33:41 +0200,
Alexandru Petrescu wrote:
> [1 ]

regards,
ryuji

-> Right, but in this case the MR does not have to change its home adress. the interruption of CN-LFN communication will occurs 
when the MR has to change its home adress.
Right ??
 
Mazen Tlais

		
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From: Mazen TLAIS <[email-masked]>
Date: Thu, 22 Apr 2004 18:44:43 +0200 (CEST)

regards,
ryuji

Mazen Tlais

---

From: Mazen TLAIS <[email-masked]>
Date: Fri, 23 Apr 2004 16:57:54 +0200 (CEST)

I have ome more question on the haha protocole, thanx
for your explanation.   

when you say :  

there could be multiple home agents attached to
different links serving the same home agent prefix. 

Do you mean that these multiple home agents that serve
the same home prefix moreover belong to the same
operator?

Mazen

		

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From: Mazen TLAIS <[email-masked]>
Date: Fri, 23 Apr 2004 16:57:54 +0200 (CEST)

when you say :  

Mazen