Subject: Re: [netlmm] draft-ietf-netlmm-mn-ar-if-03.txt

From: "Mohana Jeyatharan" <[email-masked]>
Date: Fri, 29 Feb 2008 10:31:37 +0800

Hi Pete,

I read your draft(considerable amount). I have a smal question in
section 4.2. Correct me if I am wrong.
I can understand your explanations about issues when two nodes are
physically sharing the same link but cannot have a direct
communication(different prefix). Then you explain that when neighbour
discovery is used, they may be able to directly communicate(I guess via
L2 address).

But, the point I am a bit confused with is when you say that suppose the
two nodes moves away from the same physical link then they cannot
communicate. But, what I feel is when they move the neighbour caches may
not have each others update and packets will be routed vis default
routers. I guess your case will happen, if you assume that neighbour
caches are not updated frequently. This problem may happen even in
normal node mobility. This is my small comment

BR,
Mohana

McCann Peter-A001034 wrote:
> I have just submitted a new version of draft-ietf-netlmm-mn-ar-if, 
> which you can find here:
> 
> http://www.ietf.org/internet-drafts/draft-ietf-netlmm-mn-ar-if-03.txt
> 
> Soon I expect there will be an HTML diff from -02 at this location:
> 
> http://tools.ietf.org/wg/netlmm/draft-ietf-netlmm-mn-ar-if/draft-ietf-
> ne
> tlmm-mn-ar-if-03-from-02.diff.html
> 
> Major changes:
> 
> * Modified description of step REP1 of MAG_GET_MN_ID sub-function
>   to state that PBU/PBACK exchange must complete before RA is sent.
>   I think this is necessary to get the right HNP into the RA.
> 
> * Added a MAG_GET_HI sub-function with advice on how to populate
>   ATT, MNIID, and HI fields of the PBU.
> 
> * Added a straw-man Security Considerations section.
> 
> Comments and suggestions welcome.
> 
> -Pete
> _______________________________________________
> netlmm mailing list
> [email-masked]
> http://www.ietf.org/mailman/listinfo/netlmm
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---

From: "McCann Peter-A001034" <[email-masked]>
Date: Fri, 29 Feb 2008 10:31:45 -0500

Hi, Mohana,

> discovery is used, they may be able to directly communicate(I guess

The point of ND is to find out the link layer address associated
with a given IP address.  So yes, if the interface is used on a
shared link the MNs might be able to communicate directly.

> But, the point I am a bit confused with is when you say that suppose
> the two nodes moves away from the same physical link then they cannot
> communicate. But, what I feel is when they move the neighbour caches
> may not have each others update and packets will be routed vis
> default routers. I guess your case will happen, if you assume that
> neighbour caches are not updated frequently. This problem may happen
> even in normal node mobility. This is my small comment      

If the nodes had been communicating directly, they will have each 
other's link layer addresses in the cache.  The failure will occur
when they move off the same link; the link layer addresses will no
longer be reachable.  I guess you are saying this is temporary and
should be taken care of by NUD.

In any case, the document clearly states that it is only intended
to run over a point-to-point link.  I think we should keep this
restriction and leave the shared link issues to a later document.

-Pete 

>> ne tlmm-mn-ar-if-03-from-02.diff.html
>> 
>> Major changes:
>>