Subject: [netlmm] DHCP question on draft-ietf-netlmm-pmip6-ipv4-support

From: jouni korhonen <[email-masked]>
Date: Sun, 1 Feb 2009 22:41:12 +0200

Hi,

I have a question for my clarification related to the DHCP Relay co- 
located with
the MAG case.

In Section 3.4.2. bullet four it reads "The DHCP relay agent on the  
mobile access
gateway will add the DHCP relay agent information option [RFC-3046] to  
the
DHCPDISCOVER message. The assigned IPv4 home address will be included  
in the
Agent Remote ID Sub-option of the DHCP relay agent information option.  
This
sub-option is used as a hint for requesting the DHCP  server to  
allocate that
specific IPv4 address."

In RFC3046 Section 3.2. it reads for the Agent Remote ID Sub-option that
"The remote ID MUST be globally unique."

How would this "MUST" be satisfied if private IPv4 addresses (that  
possibly even
overlap) are assigned to MNs? Are there some assumptions here that are  
not described
in the I-D?

Cheers,
	Jouni
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---

From: Sri Gundavelli <[email-masked]>
Date: Sun, 1 Feb 2009 12:52:54 -0800 (PST)

Hi Jouni,

On Sun, 1 Feb 2009, jouni korhonen wrote:

> Hi,
>
> I have a question for my clarification related to the DHCP Relay co-located 
> with
> the MAG case.
>
> In Section 3.4.2. bullet four it reads "The DHCP relay agent on the mobile 
> access
> gateway will add the DHCP relay agent information option [RFC-3046] to the
> DHCPDISCOVER message. The assigned IPv4 home address will be included in the
> Agent Remote ID Sub-option of the DHCP relay agent information option. This
> sub-option is used as a hint for requesting the DHCP  server to allocate that
> specific IPv4 address."
>
> How would this "MUST" be satisfied if private IPv4 addresses (that possibly 
> even
> overlap) are assigned to MNs? Are there some assumptions here that are not 
> described
> in the I-D?

When the LMA allocates overlapping private IPv4 addresses, this must
be done in the context of mobile node realm. That provides the logical
seperation in the control plane and the use of GRE key offers the same
in the data plane. So, the protocol is segregating the two private
address domains and the generic text in 3046 w.r.t uniqueness of
assignment which is in the context of a single plane of assignement
should not be applicable.

Regards
Sri

---

From: jouni korhonen <[email-masked]>
Date: Mon, 2 Feb 2009 14:07:03 +0200

Hi Sri,

On Feb 1, 2009, at 10:52 PM, Sri Gundavelli wrote:

>> overlap) are assigned to MNs? Are there some assumptions here that  
>> are not described
>> in the I-D?
>
>

Thanks for the clarifying answer. I wonder if the above text could
actually be in the -ipv4-support I-D as well? I found this rather
informative.

Cheers,
	Jouni