Subject: [netlmm] Comments on draft-krishnan-netlmm-pmip-sel-00

From: "Jong-Hyouk Lee" <[email-masked]>
Date: Mon, 9 Jul 2007 17:49:09 +0900

Dear colleagues.

I have some comments on draft-krishnan-netlmm-pmip-sel-00. The author claims
that the proposed mechanim could provide a client initiated selection for
PMIPv6 service. In this document, a mobile node (MN) sends the modified
router solicitation (RS) message to a mobile access gateway (MAG) to inform
whether the MN use PMIPv6 service or not. In case of receiving the modified
RS message with C bit (set 0), the MAG sends the router advertisement (RA)
message with the prefix information (MN-HNP) used for marking MN-HoA as its
response. In case of RS message with C bit (set 1), the MN will perform its
own sigaling for mobility service (e.g., Mobile IPv6).

However, there is no guarantee that the MN must send a RS message which
prior to a RA message sent from the MAG. The author should define how to
overcome. For instance, the MN using this mechanism has to receive only the
RA message responding RS message with C bit.

Also, I'm confusing with the sentance "a topologically correct prefix for
the link (i.e., Not the home prefix)". As I understand, it would use for C
bit (set 1). Is it right? If so, who is responsible for this prefix? MAG? or
LMA? (Actually, MAG sends RA messages in its subnet)

In the document, the author use a keyward, PMA. Does it stand for "Proxy
Mobility Agent"?

For myself, I like this mechanism. There need a mobility selection mechanism
initiated client (MN) in the current PMIPv6 specification.

Cheers.
-- 
Internet Management Technology Lab, Sungkyunkwan University.
Jong-Hyouk Lee.

#email: jonghyouk (at) gmail (dot) com
#webpage: http://www.hurryon.org
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From: Suresh Krishnan <[email-masked]>
Date: Mon, 09 Jul 2007 11:02:26 -0400

Hi Jong-Hyouk,
   Thanks for the comments. Please see responses inline.

Jong-Hyouk Lee wrote:
<snip>
> overcome. For instance, the MN using this mechanism has to receive only 
> the RA message responding RS message with C bit.

You are right. I had not thought about this case when I wrote the draft. 
  I need to think a bit more about this.

> 
> Also, I'm confusing with the sentance "a topologically correct prefix 
> for the link (i.e., Not the home prefix)". As I understand, it would use 
> for C bit (set 1). Is it right? If so, who is responsible for this 
> prefix? MAG? or LMA? (Actually, MAG sends RA messages in its subnet)

The topologically correct prefix is the one the MN would have got if 
there was no PMIP service on the network (i.e. the prefix of CoA). So in 
case of stateless autoconf, this would be one of the prefixes probably 
in a multicast RA sent out by the AR/MAG with the A bit set.

> In the document, the author use a keyward, PMA. Does it stand for "Proxy 

Yes. This was a term used in the earlier versions of the PMIP draft. 
Guess it has been removed.

> 
> For myself, I like this mechanism. There need a mobility selection 
> mechanism initiated client (MN) in the current PMIPv6 specification.

Sounds good.

Cheers
Suresh

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From: "Jong-Hyouk Lee" <[email-masked]>
Date: Tue, 10 Jul 2007 00:53:06 +0900

Dear Suresh.

Thanks for your responses. I have another comments based on your responses.
Please, see the inline.

> in a multicast RA sent out by the AR/MAG with the A bit set.

Well, according to your response, the mobile node (MN) will use the prefix
information sent from MAG to make its global IPv6 address in case of
stateless auto-configuration. Actually, it is a natural process. However,
you should also define who is a home agent (HA) for MN when the MN boots up
in MAG's subnet. Might be, MAG is an HA with the RA message with H set. Am I
right? If so, MAG should have the HA functions even though the MAG exists in
PMIPv6 domain (In the current PMIPv6 specification, LMA is assumed to have
the HA functions so that you should consider this).

Also, I would like to request you that the case for stateful
auto-configuration should be consider in the next version. That would make
this document stably.
Cheers.

---

From: Suresh Krishnan <[email-masked]>
Date: Mon, 09 Jul 2007 18:34:12 -0400

Hi Jong-Hyouk,

Jong-Hyouk Lee wrote:
> 
> Well, according to your response, the mobile node (MN) will use the 
> prefix information sent from MAG to make its global IPv6 address in case 
> of stateless auto-configuration. Actually, it is a natural process. 
> However, you should also define who is a home agent (HA) for MN when the 
> MN boots up in MAG's subnet. Might be, MAG is an HA with the RA message 
> with H set. Am I right? If so, MAG should have the HA functions even 
> though the MAG exists in PMIPv6 domain (In the current PMIPv6 
> specification, LMA is assumed to have the HA functions so that you 
> should consider this).

I am pretty sure there is nothing in the PMIPv6 spec to prevent or 
impede this.

> auto-configuration should be consider in the next version. That would 
> make this document stably.

Sure.

Cheers
Suresh