[ppml] 2005-1 and/or Multi6

Michael.Dillon at radianz.com Michael.Dillon at radianz.com
Thu Apr 14 09:27:59 EDT 2005

> > In IPv6, this is bad because it means that more bits
> > will have to be consumed by the global routing table,
> > communicated in BGP announcements, and processed in
> > routing calculations. 
> I don't think this assertion is accurate. Protocols carry IP addresses
> in fixed-length fields. An IPv6 prefix will always take 128 bits.

I don't whether or not BGP can reduce the number of bits in its
communications when the prefixes are shorter, however, if
the number of bits communicated between peers becomes an
issue, then the protocol could evolve to be more efficient
in its use of bandwidth. The only place where IP addresses
need to be in fixed length fields is in the IP packet headers.
I am not referring to packet headers here, but to the data
transmitted by the protocol.

Also, I don't believe that the current details of BGP are
relevant to the policy. BGP is software and it can evolve
very quickly if it needs to. Physics is the ultimate in 
hardware and does not evolve at all.

> Please don't go back to pre-CIDR, really.

Even if we defined IPv6 to have three classes of address,
Class X = /32, Class Y = /48 and Class Z = /64, it is still
not the same as pre-CIDR. The number of possible entries in
each of these classes makes it fundamentally different from
the classful IPv4 addressing scheme.

And I am definitely NOT proposing classful IPv6. Some ISPs
already have prefixes shorter than /32 and the ability to 
announce a single shorter aggregate prefix is a GOOD THING.

> Oh? Any scientific reference to that?

Here is one scientific paper
However, if you follow the press that covers semiconductor
physics and related areas, then you will find many more
references to these things. Fundamentally, the boom in 
computing and telecommunications was fueled by the ability
to make complex electronic circuits smaller by reducing
the size of the wires and components. However, our physical
world is composed of things called molecules, and you cannot
make wires thinner than one molecule. In fact, you probably 
can't even make them that thin. This is a hard limit and 
we are beginning to approach that limit.

Now scientists may indeed be able to get closer to the limit
than many now believe. But at some point, this kind of
smaller-cheaper-better-faster breaks down because it
gets harder and harder to advance. When the result becomes
smaller-pricier-better-faster, then the policies that worked
during the cheaper era, cease to work. 

> I can remember modem manufacturers saying that when 2400bps modems
> were state of the art.

Good example. Modems got faster and faster and then, at 56kbps, 
development hist a brick wall. Today, there are no modems
faster than 56kbps because the laws of physics come to play.

> Who cares?

The people who design and build routers and the people who
pay for those routers.

--Michael Dillon
P.S. the state of the art in nanowire molecular electronics can
be glimpsed here:

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