Subject: RE: [Mip4] review: draft-ietf-mip4-rfc3012bis-04.txt

From: "Jayshree Bharatia" <[email-masked]>
Date: Thu, 1 Dec 2005 16:46:15 -0600

Hi all,

I am not sure how to proceed toward supporting co-located CoA mode in
RFC3012bis. RFC3012 doesn't have any details on this and it was a
working assumption that this draft is not applicable for co-located CoA
mode.

Later in the process of updating RFC3012bis, there was a discussion that
we shouldn't be limiting use of MN-AAA extension for co-located CoA
mode. Anyway, we need to come up with some agreement now. The following
is the summary of the discussion:
- Kent and Madjid think that having clarification that there is no
challenge included in the MN-AAA extension for co-located CoA mode is
good. Although, there is no need of indicating what type of value is
used for replay protection. Although, Vijay likes to see this to be
clarified.
- Charlie suggest removing support of co-located CoA mode.

Hence, I have three options:
1. Remove the paragraph which discusses co-located CoA support (last
paragraph of section 3.1)
2. Make changes to indicate that there is no challenge included in the
MN-CoA extension for co-located CoA mode.
3. Include changes proposed by Vijay in earlier email.

Please send me reply suggesting which option you prefer.

Regards,
Jayshree

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Charles E. Perkins
Sent: Wednesday, November 30, 2005 7:05 PM
To: Kent Leung (kleung)
Cc: [email-masked]; [email-masked]
Subject: Re: [Mip4] review: draft-ietf-mip4-rfc3012bis-04.txt

Hello folks,

I do not believe the document should support co-located CoA mode.  The
point is to enable some mechanism for use by the foreign agent.  There
is no need for a mobile node to use the challenge.  No additional replay
protection is afforded.

I would prefer for the use of the extension to be
prohibited whenever the 'D' bit is set.

Even when a foreign agent is sending 'R' bit advertisements, there isn't
any significant functionality gained.

Perhaps it's technically feasible to have the challenge in
such situations, but (i) it is wasteful and (ii) I would not like to see
it become considered a mandatory part of any mobile node implementation
where co-located care-of addresses are used, for whatever reason.

Regards,
Charlie P.

PS. Please excuse if I have overlooked some e-mail about this.

Kent Leung (kleung) wrote:

>On this particular topic, I don't understand what is missing in the 
>details to support the CCoA mode?  Since the draft covers MN-AAA 
>authentication with NAS in between, I would like to see both FA (CoA) 
>and HA (CCoA) modes supported.  Where else would we be able to cover 
>just the CCoA for MN-AAA authentication if not in this draft?
>
>Kent
>
>
>  
>
>>not at this late stage. its fine as it is. however, I have
>>one comment on the support for co-located CoA mode. the draft 
>>claims it supports it but there really isnt enough detail. 
>>IMO, it should be clarified that only FA mode is described in 
>>the draft.
>>
>>    
>>
>
>  
>

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---

From: Vijay Devarapalli <[email-masked]>
Date: Thu, 01 Dec 2005 15:39:27 -0800

> 3. Include changes proposed by Vijay in earlier email.

the changes I proposed include 2. the changes I suggested
do the following

- clarify that the MN MUST NOT include the challenge extension
- clarify that in the absence of the FA, there is no challenge
generated by the network.
- clarify that in the absence of a challenge, replay protection
is provided by the identification field.

Vijay