MAST and mip based solution

["marcelo bagnulo" <marcelo@it.uc3m.es>]

Hi Dave,

I really like the MAST draft, it is really clear and attempts to benefit
from already available work.
I also liked the roadmap proposed by P. Nikander (i think it was him).
Start with a solution based in MIP, with the minimum changes to mip and then
to evolve to an optimized solution which can be something like MAST.

so i think it is important to compare mast to a mip based solution (it seems
that everyone wants to compare mast with something :-)

I can identify the following relevant points (imho)
- Deployment. I think that it is clear that mip will be available much
sooner than a mast solution. Even if some changes are required in mip to
support mh, i think that the changes imposed to nodes outside the
multi-homed site will be very limited (if not, i don't know if a mip
solution makes much sense). So i think that it is reasonable to consider a
mip based solution as a short term solution
- Overhead/MTU. I think that one of the main benefits of mast over a mip
based solution is related to the overhead and MTU reduction imposed by mip.
I mean, mip requires the usage of the HoA dest option and the type 2 routing
header when using alternative addresses. This imposes overhead and implies
MTU reduction. MAST solves these issues, since packets only carry one
address. This is a desirable feature of a more longer term solution.

However, i think that mip signaling is really similar to the one required by
MAST. for instance bu messages contain alternative address information. I
mean, i think it should be interesting to evaluate if mip messages can be
used in a MAST implementation. Moreover, i think that the mip solution can
be optimized by just avoiding the usage of the HoA destination address and
the routing header.
I mean, once that the BU has been performed, you really don't need to carry
both addresses in every packet since this state information is already at
the end nodes. This is what MAST does. so a mip based solution can evolve
towards mast in this way, i.e. conserving the packet format for signaling
and improving certain aspects as this one. Clearly much more study is
required to see how this fits.

what do you think?

Finally, the main problem that i find in mast is, as always, the security. I
mean, mast is vulnerable to time shifting attack and can be used to generate
flooding attacks, so more stuff is needed, just as in a mip based solution.

Regards, marcelo