Re: tsv-dir review of draft-ietf-mip4-fmipv4-07.txt

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Hi Hannes,


On 6/7/07 7:22 AM, "ext Tschofenig, Hannes" <hannes.tschofenig@xxxxxxx>
wrote:

> A few minor comments:
> 
> In Section 4.2 I believe you have to use RFC 2119 language for the
> following text parts:
> "
>       "Home Address" field must be the PCoA (which can be either the
>       Home Address or the co-located CoA)
> 
>       Home Agent field must be set to PAR's IP address
> 
>       Care-of Address field must be the NAR's IP address discovered via
>       PrRtAdv message
> 
>       Destination IP address must be PAR's IP address
> 
>       Source IP address must be the PCoA (which can be either the Home
>       Address or the co-located CoA)
> "
> and in 
> "
> When sent in this "reactive" mode, the Destination IP address must be
> NAR's IP address;
> "

Okay. Francis also noted this.


> 
> With respect to the predictive fast handover it seems that you assume
> that the PAR is able to detect a disconnect of the MN before the
> bidirectional tunnel is established between the PAR and the NAR. I
> understand that you don't want to describe the different ways how the
> PAR is able to detect the disconnect but you might just say that it
> somehow detects it and then initiates the procedure. Makes sense?
> 

The bidirectional tunnel is established as a result of processing the FBU
message and HI/Hack exchange. This is done in predictive and reactive cases.

See

" The Handover Initiate (HI) and Handover Acknowledge (HAck) messages
   serve to establish a bidirectional tunnel between the routers to
   support packet forwarding for PCoA.  The tunnel itself is established
   as a response to the FBU message."

below Figure 2.

> I am not sure what the purpose of Section 5 is. You refer to a long
> expired draft but why does it matter. Can this section be deleted?
> 

Purely informational. I am okay one way or the other.


> Section 6: 
> 
> You write: "
> 
> The Code values below are the same as those in [rfc4068],
>    and do not require any assignment from IANA.
> " 
> 
> Maybe you want to add "However, IANA actions are required for type
> numbers."
> 

Not all the messages need Type assignment though. In fact, only FBU and
FBack need Type assignment.
 

> In Section 6.1 you write:
> 
> "
>          Lifetime: The number of seconds remaining before binding
>          expires.  MUST NOT exceed 10 seconds.
> " 
> 
> You might want to replace "MUST NOT exceed 10 seconds." with
> "The value in this field MUST NOT exceed 10 seconds." to have a complete
> sentence. 

Ok.

> 
> In several places you write that the FBACK is bitwise identical to the
> messages used in RFC3344. I wonder whether this is true since you have a
> new type code. I think you might just write that the message layout uses
> the format of RFC 3344.
> 

I found only one occurrence of "bitwise" for FBack, at the beginning of
Section 6.2. :-)


> For the security between the access routers you write:
> 
> "
>    The HI and HAck messages need to be secured using a pre-existing
>    security association between the access routers to ensure at least
>    message integrity and authentication, and should also include
>    encryption.
> "
> 
> I think you want to recommend IPsec usage.
> 

Ok, I can add that.

> Do you assume that the two nodes, PAR and NAR, in the same
> administrative domain or potentially in different domains?
> The key management could be more difficult if the two nodes are in
> different domains.

The protocol does not make any assumption. Agree that the deployment
considerations differ based on who owns what.


> 
> In case of "Secure FBU, malicious or inadvertent redirection" isn't it
> quite likely that an attack by a mobile node can be punished later since
> the key management used to create the security association for the FBU
> is likely going to be associated with the network access authentication
> and hence the identity of the user can be traced back.

It's possible to trace it, yes.

> 
> There are certainly some impacts on transport layer protocols due to the
> way how the handover procedure works. I am sure that there are papers
> available (maybe even written by the authors) that describe some of the
> affects. It could be useful to point to such a paper.

We wrote a paper for ACM CCR a while ago (October 2001). More recent results
are documented in an upcoming book.

Thanks for your review.

-Rajeev

> 
> Ciao
> Hannes

-- 
http://people.nokia.net/~rajeev




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