Steve Deering wrote:
> At 8:12 AM -0800 2/16/01, Ed Gerck wrote:
> >1. there is a natural need for heterogeneous address systems and,
>
> Agreed.
>
> >2. therefore, there is a natural need for address translation.
>
> Only if there's some need to interconnect them, and even then only as
> a temporary measure, if at all, because there is an alternative and
> preferable way to deal with heterogeneous address systems -- and the
> only long-term successful way if history is any guide -- which is to
> layer a homogenous address system on top of them, which is the basic
> idea behind IP.
The other way, which can be theoretically justified as well, is to implictly
define a "third system" that defines an internal reference for a set of
relationships between the two address spaces. This third system
can take the form of a NAT. Note that this third system is not an address
space, much less a homogeneous one.
And, as "The Tulip" discussion thread showed, such a NAT can take various
forms that could be defined in an RFC with interoperation in mind. In
particular, the capability of including the outside origin address:port as well as
the global destination address:port in the translated packet which has the usual
NAT-defined local destination address:port and the local origin address:port.
Cheers,
Ed Gerck
