[Mip4] RE: Pre-Registration Request routing issue in Low Latency Handoffs in Mobile IPv4 Draft --

Hi Karim, 

That's exactly what I am referring to. We do need something like a
secure interface between oFa-nFa for the Registration Request destined
to nFA. This will reduce the delay, that exists due to it going to the
HA twice (in case of Reverse Tunneling), which could be crucial in a
faster handoff process.

Will be looking forward to the list of issues that you are taking up.

Thanks and Best Regards
Manish Chugtu

-----Original Message-----
From: Karim El Malki [mailto:karim@athonet.com] 
Sent: Sunday, March 11, 2007 10:36 PM
To: Chugtu Manish-a22653
Cc: mip4@ietf.org
Subject: Re: Pre-Registration Request routing issue in Low Latency
Handoffs in Mobile IPv4 Draft --

Hi Manish,
If I understand the problem correctly, you're saying that it would take
longer for the Registration Req to reach nFA in the case of reverse
tunnelling since it would have to traverse the HA twice. This may or may
not delay the actual handoff depending on the anticipation time and the
FA-HA delay. Typically the wireless leg and handoff time tend to
compensate for additional fixed delays so there would not be a problem.
However there may be a case where the overall handoff time is impacted
(do you have any practical case?) thus we could introduce shorter path
routing for the reverse tunnelling case. The oFA has knowledge of its
nFA neighbour addresses and could further filter incoming packets (RR?)
destined to the nFA routing them through the secure oFA-nFA interface.
That would be compatible with reverse tunnelling and the packets
wouldn't be dropped by source address filters.
There's a couple of issues, possibily including this one, that I'd like
to take up in a revision of the draft following RFC publication (in RFC
Ed queue). I'll put forward a list.
Regards,
Karim

Chugtu Manish-a22653 wrote:
> Hi Karim,
>  
> This is regarding the method of handling Pre-Registration request by 
> oFA in the /Low Latency Handoffs in Mobile IPv4 / 
> <http://www.ietf.org/internet-drafts/draft-ietf-mobileip-lowlatency-ha
> ndoffs-v4-11.txt>/ Internet Draft./ According to me, the way it is 
> handled by the draft might have a problem as follows:
>  
> Pre-Registration according to draft should be treated as *normal IP 
> packet which has to be routed **to the nFA by oFA*. But since the MN 
> is already registered to oFA and lets say we have Reverse Tunneling 
> enabled on oFA, any packet with the source address as Home Address of 
> MN would be tunneled to HA including the Pre-registration packet, 
> which is not what we want.
>  
> Also, in this case if somehow we route the Pre-Reg packet to the nFa 
> by-passing reverse tunneling (by defining some routing policies or may

> be by coding it in such way) , it still may not be a good idea, since 
> one of the main reason for reverse tunneling is to avoid packet drops 
> for topologically in-correct source address.
>  
> So we would have to define a specific way to handle Pre-Reg packets in

> reverse tunneling case eg: Might need to tunnel it to the nFA. Please 
> let me know your inputs and also in case I am missing something here. 
> In case you agree to the problem, do you think we might need a 
> revision to the draft which states and addresses the above mentioned 
> problem
>  
> Best Regards
> Manish Chugtu

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