Re: Comments on draft-bagnulo-multi6dt-hba-00.txt

[Jari Arkko <jari.arkko@piuha.net>]

Hi Marcelo,

> Yes,
> I mean, i would do the following.
> first the communication is set up, and at some moment in time the CGA 
> parameters are exchanged. For now, no hash calculation.
> Suddenly, an different locator needs to be used. So at this point, i 
> would run the verification process, implying a hash calculation.
> then as long this is the locator that is used, i don't think that 
> additional verification are needed, you just need to remember that this 
> locator is OK
> So, i would say that for a HBA set with n prefixes, the maximum number 
> of hash verifications needed is n (independently of the number of 
> packets exchanged with each locator)

I agree that you do not wish to verify HBA or CGA on a per-packet
basis. (If that were the case, it would be horrible.)

As for the number of hash verifications, it would seem that
you only have to verify those addresses that you actually use
for exchanging packets with the peer. That is, if there is no
problem you don't necessarily have to verify anything. And
if you have a problem, it suffices to test the addresses
that you actually end up switching to instead. (I'm still
wondering whether the test packets sent to address X need
verification of X; there may be some denial-of-service issues
if we don't do that.)

--Jari