nanog mailing list archives

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


From: Owen DeLong <owen () delong com>
Date: Sun, 30 Jan 2011 09:48:00 -0800


On Jan 30, 2011, at 8:39 AM, Leen Besselink wrote:

On 01/25/2011 11:06 PM, Owen DeLong wrote:


"640k ought to be enough for anyone."

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 ?:

Yes... I left a word out of my sentence... I think it is unlikely we will see
COMMON machines with much more than a terabyte of RAM in
the lifetime of IPv6.

Sure, there will be the rare monster super-special-purpose thing with
more RAM capacity than there is storage in many large disk farms, but,
for common general purpose machines, I think it's safe to say that
47,223,664,828,696,452,136,959 terabytes ought to be enough for
anyone given that even at the best of Moore's law common desktops
will take 9 or more years to get to 1 Terabyte of RAM.

"...IBM can cram 1 TB of memory into a 4U chassis or 2 TB in an
eight-socket box in two 4U chassis..."

http://www.theregister.co.uk/2010/04/01/ibm_xeon_7500_servers/page2.html
http://www.theregister.co.uk/2010/04/01/ibm_xeon_7500_servers/

I don't know who will use it or how much they will need to pay for it or
even when they will be available,
but they are talking about it (in this case at the last CEBIT in March).

People are building some very big systems for example with lots and lots
of virtual machines.


Yes... My intent, like the 640k quote, was aimed at the common desktop
machine and primarily to show that since 1 TB is an inconceivably large
memory footprint for any normal user today, it's going to be a long long
time before 47,223,664,828,696,452,136,959 TB comes up short for
anyone's needs.

Owen




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