ietf
[Top] [All Lists]

RE: Stupid NAT tricks and how to stop them.

2006-03-28 11:18:26
    > From: "Gray, Eric" <Eric(_dot_)Gray(_at_)marconi(_dot_)com>

    > I think the "street address" analogy is not close enough - anymore
    > than longitude and latitude numbers or any other description of
    > physical location.

No, it's a very good analogy, because the road network is a very good analog
to the data network. To see how, let's do a though-experiment.

Embed the road-network, not on the surface of a solid sphere, but on the
surface of a flexible hollow spherical surface. Now, distort that surface
arbitrarily. The location (in spatial coordinates) of any place on that road
network has changed totally - but the set of directions you'd use to get
from one point in the road network to another ("go down road A until you
meet the junction with B, and turn onto B in the direction of C", etc, etc)
remains unchanged.

What is most important about both the data network, and the road network, is
the *connectivity pattern* - what connects to what. That's because packets
are (usually) constrained to travel down links, and vehicles are (usually)
constrained to travel down roads.

    > The problem with physical location portability is that the location
    > remains even if you're not in it.

But the exact same thing is true of a network - Port #0 on ISP A's router R
is the same place in the network (i.e. you use the same directions to get to
it - see above) whether company X or company Y is plugged in there - just as
126 Main Street is the same building, whether company X or company Y is
housed there.

    > Number assignments, however are substantially more portable.

Saying that doesn't make it so. You can easily (sic) change street names
too, to make a street name "portable".


    > It is certainly possible for an IPv6 address pool manager to allocate
    > personalized IPv6 addresses from an IPv6 address pool that they manage
    > and thereby assume responsibility for end-delivery

That's just a translation service from *virtual* addresses to real ones -
those IPv6 "addresses" aren't the names of locations in the network: if the
pool manager *actually wants to get packets* to those entities, it is going
to have to translate those "addresses" into the real addresses at which
those entities can be found.

        Noel

_______________________________________________
Ietf mailing list
Ietf(_at_)ietf(_dot_)org
https://www1.ietf.org/mailman/listinfo/ietf