moving to IPv6

Phil Howard phil at
Sat Nov 1 18:11:53 UTC 1997

Paul Ferguson writes...

> [playing devil's advocate here]
> Of course, there is a rather large contingent of the
> Internet community that is of the opinion that IPv6 is
> a solution in search of a problem.

And we can most certainly go for a long time with IPv4.  Just how long
that will be depends on things like new technologies coming along that
can impact how people use the Internet.

IPv4 space is not enough for dedicating 1 IP address to every person.
The question is when (or if) that will be needed.  Under the current
user paradigm of dialing up to a provider for a short while to surf,
it may be indefinite.  And that demand will be rolling off to level
out at some point in the U.S.

There are also increased costs involved in the processes being used to
manage allocations of IPv4 space.  Space is allocated in pieces as needed,
which means either renumbering networks or introducing more routes into
the BGP4 stream.  One big /64 of IPv6 space will last virtually any ISP
a century, unless they start trying to assign every grain of sand.  And
there would be just one route for all that.  Administrative costs, once
the software is in place that handles it, will be much less than with
IPv4 space.

With IPv4 space being managed better with CIDR, we do have more time to
find the right way to deploy IPv6.  I remember the panic of a few years
ago.  I was even called to ask if my then-employer would be able to
return part of their class B assignment.  The big problem I see today
is not the amount of space, but the complexity of managing tight space,
and things like the number of routes involved.

Whether to IPv6 or not, maybe we should be looking at what next for BGP4.

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