Using IPv6 with prefixes shorter than a /64 on a LAN

Valdis.Kletnieks at Valdis.Kletnieks at
Sun Jan 30 11:57:30 CST 2011

On Sun, 30 Jan 2011 17:39:45 +0100, Leen Besselink said:
> On 01/25/2011 11:06 PM, Owen DeLong wrote:
> >
> >
> >> "640k ought to be enough for anyone."

Remember that when this apocryphal statement was allegedly made in 1981, IBM
mainframes and Crays and the like were already well in to the 64-256M of RAM
area, and it was intended to apply to consumer-class machines (like what you'd
run Windows on).

> > If IPv4 is like 640k, then, IPv6 is like having 47,223,664,828,696,452,136,959
> > terabytes of RAM. I'd argue that while 640k was short sighted, I think it is
> > unlikely we will see machines with much more than a terabyte of RAM
> > in the lifetime of IPv6.
> >
> I would be very careful with such predictions. How about 2 TB of RAM ?:

OK. A petabyte of ram instead. Better? Then IPv6 is like having
47,223,664,828,696,452,136 petabytes of RAM.  Or go to an exabyte of ram.
That's a million times the current highest density and still leaves you a bunch
of commas in the number.

We seem to be managing at best, at the bleeding edge, one comma per decade. And
note that the change in units from kbytes to terabytes itself hides 3 more

In any case, the fact you can stick a terabyte of RAM into a 4U Dell rack mount
that sucks a whole lot of power doesn't mean we're anywhere near being able to
do it for consumer-class hardware.  Remember, much of the growth is going to be
in the embedded and special purpose systems - the smart phone/PDA/handheld game
system arena, etc.  How many fully loaded R910's will Dell sell, and how many
iPhones will Apple sell? How long before a Blackberry or an iPhone has a
terabyte of RAM? (For that matter, when will they get to a terabyte of SSD

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