RE: [Mip4] I-D Action:draft-ietf-mip4-nemo-v4-base-07.txt

["John.zhao" <[e-mail]>]

Hi,Christophe and Alex
 	Yes,I think I have though it as you have just mentioned below. But,
in section 7, just as Alex has pointed, the first paragraph mention that HA
can use the optimization encapsulation, but to those packets sent from MR,
there isn't the related choice. So I just pointed this one hope authors can
clarify and keep the consensus with that <fa-01> doc.
	
	Best Rgds,
Thanks.
John.zhao
> John, Alex,
> 
> My understanding is that the base NEMOv4 specification
> (draft-ietf-mip4-nemo-v4-base-07.txt) requires double encapsulation to
> be used for the Foreign Agent CoA mode, but makes it optional for the
> Collocated CoA mode. In other words, in Collocated CoA mode, the spec
> allows (and actually encourages = SHOULD) the simple (bi-directional)
> encapsulation between MR and HA to be used.
> 
> The double encapsulation is required in the FA CoA mode, to ensure
> transparency with respect to legacy (RFC3344) Foreign Agent. If simple
> encapsulation only would be used, the FA would need to be able to
> forward a packet addressed to an LFN address while only the MR's HoA is
> present in the FA's visitor list...and the packet would be dropped. The
> draft "FA extensions to NEMOv4 Base" (draft-ietf-mip4-nemov4-fa-01.txt)
> aims at addressing this specific issue by defining extension to FA to
> make it NEMOv4 aware and thus allow the use of simple encapsulation
> (i.e. of the sole FA<->HA tunnel and nor more the additional inner
> MR_HOA<-->HA tunnel).
> 
> Can authors confirm this was the intention of the two different specs
> (i.e. the NEMOv4 base spec allowing simple encapsulation for the
> Collocated CoA mode, while a separate doc specifying it for the FA CoA
> mode)?
> 
> I have not checked the last version of the base NEMOv4 spec to determine
> if the current text is explicit enough about these aspects. John what do
> you think?
> 
> Thanks
> Christophe.
> 
> Alexandru Petrescu wrote:
> > John.zhao wrote:
> >> Hi,all In the section 7, to co-located mode MR, it seems that it can
> >> also send traffics based on the optimization and only tunnel once with
> >> the CoA as its source address. Right?
> >
> > Hi John, thanks for pointing this.  The intention is indeed to have the
> > simple encapsulation (optimization of double encapsulation) described in
> > a separate document and not here.
> >
> > I would like to know which paragraph in section 7 read made you think
> > optimization is used?  I would like to identify it and keep track.
> >
> > I could think of the following in section 7:
> >> For optimization, the Home Agent SHOULD only encapsulate the packet
> >> with the tunnel header (source IP address set to Home Agent and
> >> destination IP address set to CoA) for Collocated CoA mode.
> >
> > Also know that I'm not sure who/how/when can make modifications to the
> > document, since it's advanced a bit past the WG discussion.
> >
> > Alex
> >
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> 
> 
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