Christian Huitema wrote:
>
> Let's observe first that while there have been many proposal for variable
> length addresses, the length are always somehow bounded. For example, there
> will be an address length field in the packet header, and there will be some
> limited number of bits to encode the length. Even if the length was not
> technically limited, there will be practical considerations, such as the
> inefficiencies that accrue when headers are too large. So, if the provider is
> intent at limiting subscriber capacities, they could always simply allocate a
> very long address to subscriber, close to the practical maximum. Voila, no
> private numbering anymore.
>
This is, of course, true from a technical standpoint, but it doesn't
seem to work out that way in terms of psychology. Consider, again, the
example of the PSTN, where there is such a limit and it's relatively
small; currently 15 decimal digits. Very few countries have numbers
that long, but the difference seems to be between countries which have
chosen an all-fixed-format allocation scheme and those that have chosen
a prefix code (variable length) allocation scheme.
If someone is actively trying to prevent suballocation, then, of course,
you're absolutely right. However, I suspect that most of that is
incompetence rather than malice; hoarding instict combined with "it's
what we always have done."
> Economic tussles should be solved by economic arguments. If it is in the
> economic interest of providers to provide multiple addresses to subscribers,
> they will indeed do it. Otherwise, the only technical solutions that can
> succeed against an uncooperative provider are those where a private network
> is undistinguishable from a single host.
That's a very technologically pure idea, and sometimes it is correct.
However, human behaviour can be changed by changing the parameters
around it, sometimes in nonintuitive ways.
-hpa
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