Re: [Hipsec] Comment on VIA_RVS parameter - 5204 & 06 -bis

[Robert Moskowitz <[e-mail]>]

On 09/26/2016 09:08 AM, Miika Komu wrote:
> Hi,
>
> On 09/16/2016 02:45 PM, Robert Moskowitz wrote:
>>
>>
>> On 09/16/2016 06:57 AM, Tom Henderson wrote:
>>>
>>>
>>>
>>> On Thu, 15 Sep 2016, Robert Moskowitz wrote:
>>>
>>>> 5206-bis specifies how to user RVS for the 'double-jump' mobility
>>>> problem.
>>>>
>>>> 3.2.3 1) says:
>>>>
>>>> 1. The mobile host sending an UPDATE to the peer, and not receiving
>>>> an ACK, MAY resend the UPDATE to a rendezvous server (RVS) of the
>>>> peer, if such a server is known.
>>>>
>>>> But it DOES know there is an RVS IF the I1 had FROM and RVS_HMAC
>>>> parameters and it had created a VIA_RVS parameter to send in the R1.
>>>
>>> Yes, but the responder may not know the initiator's RVS even if the
>>> the responder's RVS was used, and it also may be the case that neither
>>> host's RVS was involved in the session setup.
>>
>> I see now.  As currently speced, R has no way of learning I's RVS. The
>> 'easy' way to fix this is for I to include a VIA_RVS in the I2 packet
>> for mobility support.
>>
>> "If you every want to get back to me, I can always be reached at this
>> number".
>
> do you actually need the initiator's RVS for double jump? I think the 
> responder's RVS is enough.

Then the Initiator's UPDATE must be successful before the Responder can 
perform its UPDATE successfully.  This way they can operate in parallel.


>
>>>> This VIA_RVS provides the knowledge and locator of the peer's RVS.
>>>>
>>>> In fact an aggressive mobility UPDATE would be sent simultaneously to
>>>> the host and its RVS.  If the host had not moved itself, it gets both
>>>> and drops the one from the RVS.
>>>
>>> I believe that Baris Boyvat on the InfraHIP project was looking a
>>> while back at such an approach to fast mobility; it was called
>>> 'shotgun' approach to mobility and multihoming (try all candidates
>>> simultaneously), if I remember correctly.
>
> Yes, the idea was to send I1 (or UPDATE) through all the available 
> address pairs, but I think the idea is now achieved in a more 
> controlled way in draft-ietf-hip-native-nat-traversal-13

I will look at that.  But what if there is no NATs to traverse? That 
there are 2+ interfaces, all native IPv6?

But I will review nat-traversal.

thanks

Bob